A meta-evaluation of smoking cessation intervention research among pregnant women: improving the science and art

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1 HEALTH EDUCATION RESEARCH Theory & Practice Vol.13 no Pages A meta-evaluation of smoking cessation intervention research among pregnant women: improving the science and art Richard A. Windsor, Neal Richard Boyd 1 and C. Tracy Orleans 2 Abstract In 1986 Windsor and Orleans described guidelines and standards to evaluate the quality of smoking cessation intervention research among pregnant women. This paper presents a metaevaluation (ME) of the evaluation research in this area from 1986 to ME is defined as a systematic review of and quasi evaluation research using a standardized set of methodological criteria to rate the internal validity efficacy or effectiveness of intervention results. Five criteria were used to rate 23 smoking cessation intervention studies among pregnant smokers in prenatal care: (1) evaluation research design, (2) sample representativeness, sample size and power estimation, (3) population characteristics, (4) measurement quality, and (5) replicability of interventions. Eleven studies had sufficient methodological quality to produce results of high internal validity. Poor measurement of smoking status, patient selection biases and incorrect calculation of quit rates were the major methodological weakness. Recommendations for future evaluation research are made. Senior authorship is equally shared between the first two authors Robert Wood Johnson Foundation Smoke-Free Families National Program Office, University of Alabama at Birmingham, Department of OB/GYN, 560 OHB, Birmingham, AL , 'Fox Chase Cancer Center, Philadelphia, PA and 2 Robert Wood Johnson Foundation, Princeton, NJ 08543, USA Introduction Smoking during pregnancy (Simpson, 1957; USDHEW, 1964; Butler et al, 1972; Hasselmeyer et al, 1979; USDHEW, 1979; USDHHS, 1980, 1990; Wainwright, 1983) significantly increases fetal, infant and maternal risk. Since the Surgeon General's landmark report in 1964 on the health effects of smoking, the prevalence rate of 35% (NCHS, 1988; Stockbauer and Land, 1991) among women of childbearing age has slowly decreased. Currently, approximately 20% (Fingerhut et al, 1990; Overpeck and Moss, 1991; Stockbauer and Land, 1991; Leshner, 1994) or about of the 3.9 million women who deliver each year are estimated to have smoked cigarettes during pregnancy. Because of the persistence of this problem among this high-risk group, evaluations of the efficacy and cost-effectiveness/cost-benefit of smoking cessation and significant reduction methods (Li et al, 1992, 1993; Windsor et al, 1993) continue to be a national public health priority (USDHHS, 1991, 1995). While insight in the literature continues to expand, a critical review of completed intervention studies represents an essential, on-going step to improve the health education science and practice base in obstetrical care. Haynes et al. (1979) applied six methodological criteria to rate the validity of 1400 patient education/compliance studies: (1) rigor of evaluation design, (2) selection and specification of study sample, (3) specification of illness or condition, (4) quality of compliance measures, (5) description of the therapeutic regimen, and (6) definition of compliance. Windsor and Orleans (1986) adapted O Oxford University Press 419

2 R. A. Windsor et al. these criteria and methods to evaluate the methodological quality of smoking cessation intervention research among pregnant women. They rated the quality of or quasi- evaluation research on five dimensions: (1) evaluation research design, (2) sample representativeness and sample size/power estimation, (3) specification of population characteristics, (4) quality of measurement, and (5) appropriateness and replicability of intervention and control procedures. Summary and qualitative rating scores of intervention research from 1972 to 1985 is presented in Tables I and II. The major strength of the eight studies in their 1986 meta-evaluation (ME) was the use of a randomized design. The major weakness was poor measurement the lack of biochemical verification of self-reported smoking status. Methodological areas that also needed improvement were: (1) documentation of baseline equivalence of the study groups, (2) standardization and monitoring of and control procedures, (3) documentation of the degree of representativeness of the study sample, and (4) documentation of the characteristics of subjects who refused to participate, were ineligible and/or were lost to follow-up. A MEDLINE search was conducted through the National Library of Medicine-National Institutes of Health retrieval system to identify published research from 1986 to 1998 in smoking cessation in pregnancy. Communication with principal investigators in the field identified completed but unpublished studies. This process yielded 23 or quasi- studies. Because this area of research is so specialized, we believe our review and ongoing active network of investigators identified the universe of and quasi- studies, published and unpublished, in this area. In this paper, we refer to a study as only if it randomly assigned patients to an Experimental group (E) or a Control group (C). A quasi study was defined as a study that established a Comparison (Q and E group by a non-random process. All studies not selected in this ME lacked acorc group, or used ac_ group with serious selection biases. This paper presents a ME of 23 evaluation research studies from 1986 to 1998 in smoking cessation during pregnancy. ME is defined as: the systematic review of or quasi intervention research using a standardized set of methodological criteria to assess the degree of internal validity efficacy or effectiveness of evaluations of health education intervention methods (Windsor et al., 1994). Evaluation research critiques Descriptions of the 23 intervention studies appear in Table HI. The following section presents in chronological order a brief summary and methodological critique of each study. Study 1 Lilley, 1986 This study used an design to evaluate individual counseling plus anti-smoking advice among pregnant smokers in a Newcastle, UK hospital. The intervention consisted of 10 min anti-smoking advice plus anti-smoking pamphlets compared with usual care of whatever the quit smoking advice was offered in prenatal practice. Several methodological weaknesses were apparent. While the sample was reported as representative, it was small and data on patient recruitment were not presented. Patient and household member smoking history at the first prenatal visit was presented. Variables such as parity, education, age, race, mean month of entry into care and patients who refused to participate were not described. Smoking status was measured by self-report only. Patients lost to follow-up were not counted in the quit rate calculation. Although E and C group procedures were presented, little information about the intervention's theoretical basis, number of sessions and session duration was provided. Study 2 MacArthur, 1987 This study applied a quasi- design to evaluate whether advice to quit smoking and discussion of effects of smoking on fetal develop- 420

3 Table I. Evaluation research of smoking cessation for pregnant women Principal investigator Design Sample size Exclusionary criteria Smoking measurement Time Quit rates (%) Donovan ( ) Baric et al. (1975) Locb et al. ( ) Ershoff et al. ( ) Bauman et al. (1981) Burling et al. (1983) Sexton and Hebel ( ) Windsor et al. (1982-S4) "Self-report only. "Substantial attrition follow-up. + = Recomputed. quasi- E = 263 C = 289 E = 63 C = 47 E = 500 C = 500 E = 57 C = 72 E = 36 C = 43 E = 105 (65) C = 104 (74) E = 388 C = 395 C, = 104 E, = 103 E 2 = 102» 5 cigarettes 30 weeks pregnant < 20 weeks pregnant < 24 weeks pregnant none none * 10 cigarettes < 18 weeks pregnant S 32 weeks pregnant self-report self-report self-report urine SCN (E only) CO CO saliva SCN saliva SCN 1st visit + end-point varied (baseline) + 11 weeks 1st visit + delivery 1st visit + delivery 2 months 1st visit + 6 weeks 24 weeks 28 weeks + 34 weeks 1st visit + 32 weeks 1st visit 2nd/3rd visit + last month not reported E = 14" C = 4«E= 15 b C = 14 b E = 28 C_ = 14 E = 6 C = 3 E = 10* + C = 3* + E = 27 C = 3 E, = 14 E 2 = 6 C, =2 c os p. o OQ O. o

4 R. A. Windsor et al. Table IL Methodological ratings of evaluation research for pregnant smokers Principal investigator (year) 1 Design 2 Sample 3 Characteristics 4 Measurement 5 Intervention Rating score 1 Baric (1975) 2 Donovan ( ) 3 Loeb ( ) 4 Ershoff ( ) 5 Bauman (1981) 6 Burling (1983) 7 Sexton ( ) 8 Windsor ( ) Range ment increased cessation rates and infant birthweight among smokers in an English maternity hospital. Women in the E group were advised by their doctor to quit smoking and were given antismoking pamphlets. The C group received routine advice to stop smoking. Although a quasi- study, the large number of patients (1156) provided sufficient sample size-power for a comparison of cessation rates. E group andc_ group data documented equivalence for demographic, behavioral and health status variables. Data on refusals, however, were limited. Smoking status was based only on self-report While urinary cotinine was obtained on some patients, collection was discontinued when this measure did not differentiate between levels of patients' smoking. No psychosocial data were reported. Data on patient recall of exposure to intervention messages raises a question about the level of intervention implementation. E group women in their first pregnancy were more likely to have received all of the intervention. Their smoking cessation rates and infant birthweights were higher than thec_ group primigravida women or multigravida E group and C_ group women. Cessation rate and birthweight data were compromised by the lack of biochemical validation of end of pregnancy smoking status. While the intervention components were described, the length of patient sessions was not reported. Study 3 Gillies, 1988 This study used a quasi- design to evaluate efficacy of a multi-component intervention of anti-smoking advice by a midwife, carbon monoxide monitoring, anti-smoking pamphlets, and the offer of self-help groups on smoking cessation and reduction in an English maternity setting. The C group received only doctor's advice to quit and a generic anti-smoking pamphlet. A large sample (N = 840) assured sufficient statistical power. Data on the equivalence of E and C group matching by social class and smoking status of the significant other were presented. Data on age, estimated gestational age (EGA), education and parity would have provided additional evidence of baseline equivalence. Measurement was limited to self-reports. While a carbon monoxide monitor was available for E group patients, it was not used to corroborate self-reports. Quit rates were only reported for patients who completed post-test questionnaires. Patients lost to follow-up were not counted as smokers in calculation of quit rates. No data were presented to document intervention content, intensity and duration of patient advice, and the degree of intervention implementation. Study 4 Ershoff, 1989 This was a very strong study which examined the efficacy of a serialized self-help intervention from the 20th week of pregnancy in a Southern California HMO population. Patients in the E group received a 3 min review of the first cessation booklet by a health educator and notification that the remaining seven booklets would be mailed weekly. The C group received provider-initiated advice to quit An design evaluated 422

5 A meta-evaluation of smoking cessation program efficacy with sufficient statistical power. A baseline description of patient demographic, health status and psychosocial characteristics documented equivalence of participants and refusals. Self-reports were verified by urinary cotinine at multiple points in pregnancy. The description of the intervention confirmed its appropriateness and replicability, and process evaluation data demonstrated a high level of intervention delivery. Study 5 Messimer, 1989 This study evaluated the impact of the American Lung Association's (ALA) Because You Love Your Baby booklet in private obstetrical practices in Michigan. Patients in the E group were counseled to quit smoking by their doctor while the C group women received routine advice to quit that was standardized across all C group practices. Although an design was used, the sample size estimates were based on a five-cigarette-per-day reduction between the E and C groups. The study's primary outcome variable was cessation, however, not reduction in the number of cigarettes smoked. No data about parity, baseline smoking rate, mean EGA at the first prenatal visit, ethnicity, ineligible patients, refusals and dropouts were presented. Measurement of smoking status was based on selfreports. Patients lost to follow-up were not included in the quit rate calculations. The intervention was tailored to pregnancy, although its description lacks specification of the length of patient counseling sessions. Study 6 Mayer, 1990 This study evaluated a multi-component intervention of counseling and self-help smoking cessation guides in a Michigan Women's, Infants and Children (WIC) setting using an design. The multi-component intervention consisted of a 20 min risk counseling and behavior change session delivered by a health educator plus self-help materials adapted to pregnancy. This component was compared with a health educatordelivered risk information component that included a 10 min session about risks of smoking and with usual care advice to quit supplemented by antismoking pamphlets. Although study group sizes were small, the use of an design, recruitment of over 80% of eligible patients and an attrition rate of less than 20% represent methodological strengths of the study. Population characteristics were well described. Saliva thiocyanate was used to verify only one-third of the selfreports. Patients lost to follow-up were appropriately counted as failures. Whereas the E and C group procedures were adapted to the WIC setting, an incomplete description may make replication of these procedures difficult. Study 7 Haddow, 1991 An design was used to evaluate the impact of a smoking cessation self-help guide plus personalized feedback of patients' baseline cotinine and its likely impact on their infants' birthweight among pregnant women smoking 10 cigarettes per day. The intervention, delivered by the physician, also included a second cotinine feedback 1 month after the baseline assessment to provide patients information on progress. This study's large sample size (E = 1343 and C = 1357) provided ample statistical power to determine behavioral outcomes. The description of study characteristics was thorough. However, die reported quit rate for the E group was based on a second cotinine measurement of only 48% of the E group. Patients lost to followup were not counted as failures. Inclusion of these patients in the denominator reduces the reported E group quit rate to 7.6%. Also, the second cotinine test was performed at approximately 4 weeks after the intervention a mid-pregnancy measure. No biochemical tests were performed at the end of pregnancy to document smoking behavior. The C group quit rate was not reported and no explanation was given on why this rate was not included. Incomplete measurement was a serious bias, preventing attribution of the differences in patient cessation and infant birthweight to the intervention. No information about the theoretical bases of the smoking cessation guide or counseling session length were presented. Study 8 Hjalmarson, 1991 This study evaluated a physician-delivered risk counseling and a self-help smoking cessation guide 423

6 Table III. Smoking cessation evaluation research for pregnant women Principal investigator Design Sample size Exclusion criteria Measurement Time Quit rates (%) Lilley (1986) Me Arthur (1987) Gilles (1988) Ershoff (1989) Messimer (1989) Mayer (1990) Haddow (1991) Hjalmarson (1991) O'Connor (1992) Price (1992) Rush (1992) quasi- quasi- quasi- E = 74' C = 73' E = 493 = 489 E = E = 126 C = 116 E = 57" C = 60 E, =72 E 2 = 70 C = 77 E = 1343 C = 1357 E = 492 C = 231 E = 100 C = 109 E, = 71 E2 = 52 C = 70 E = 175 C = 144 < 28 weeks pregnant. = 10 cigarettes/day Self-reported smoker at 1st prenatal visit < 28 weeks pregnant, self-report smoker or recent quitter at 1st prenatal visit «18 weeks pregnant, 7 cigarettes/week, English speaking * 28 weeks pregnant, first visit 1 cigarettes/day < 20 weeks pregnant, 9> 10 cigarettes/day < 12 weeks pregnant, 1 cigarette/day 34 weeks postpartum < 31 weeks pregnant, 1 cigarette/day 6 weeks postpartum < 28 weeks pregnant < 20 weeks pregnant. 1 cigarette/day self-report self-report self-report urine cotinine self-report 1/3 SCN at postpartum serum cotinine postpartum salivary SCN at at hospital urine cotinine CO CO 1st visit. end of pregnancy end-point end of pregnancy 6 months postpartum 1st visit + 26th and 34th week 1st visit. end of pregnancy end of pregnancy postpartum mid-pregnancy Cpp = weeks Epp = 15.8 third trimester, 1st visit. end of pregnancy end of pregnancy E = 5.4' C = 1.4 E = 9.0" = 6.0 E = 7.4 C = 3.4 E = 22.2 C = 8.6 E = 26.3" C = 13.3" E, E 2 = 7.1 C = 2.6 E = 7.9 C = NR b E34 = 12.6 C34 ~ 8.6 E = 1 C = " E, = 5.6 E 2 = 3.8 E = 1.4" E = 10.4 = 5.4 I

7 King (1992) quasi- Q = 211 E = 951 Petersen (1992) C, = 78 E, =71 Windsor(1993) E = 400 C = 414 C= 100 Seeker-Walker (1994) E = 188 C = 226 Valbo (1994) E = 54 C = 50 Kendrick (1995) Lillington (1995) Hartmann (1996) Gielen(1997) Walsh (1997) Lowe (1998) Gebauer (1998) Recalcuted. b Not Reported. c Self-reported. quasi- E= 1467 C = 1767 E = 79 C = 146 E = 107 C = 100 E = 125 C = 121 E = 127 C = 125 E = 44 C = 34 E = 84 C = 94 * 34 weeks pregnant * 18 years «24 weeks pregnant < 32 weeks pregnant 1 puff - 7 days * 25 weeks pregnant 1 cigarette/day > 18 weeks pregnant, 10 cigarettes/day at week 18 of pregnancy "S 25 weeks pregnant, 1 puff - last 7 days none,» 36 week pregnant < 32 week pregnant 1 puff - last 7 days none self-report urine cotinine saliva cotinine urine cotinine significant other urine cotinine self-report CO 5 p.p.m. saliva cotinine urine cotinine urine cotinine saliva cotinine end of pregnancy 1st visit + 6 months mid-pregnancy end pregnancy 1st visit. 36 weeks, postpartum baseline, at delivery E = 5 e = 5- E, = I9 1 C = 18 1 E = 14.3 C = 8.5 = E = 14 C = ll c E = 20 C = 4 1st visit. E 36 and 12 weeks postpartum C = E = 12" postpartum Q = 12 E = weeks C = 10 3rd trimester E = months postpartum C = 5.6 E = 12 4 and 34 weeks postpartum C = 0 1st visit. 20 weeks 1st visit weeks E = 9 C = 0 E = 16 C = 0 n < el c o. o 3 B o P a. o D

8 R. A. Windsor et al. compared with usual care advice to quit smoking among a group of pregnant Swedish smokers in Gothenberg. The cessation guide was a Swedish adaptation of A Pregnant Woman's Guide to Quit Smoking (1991). Multiple strengths included use of an design, a large sample size and recruitment of 85% rate of the eligible smoking cohort from 13 of 14 public health maternity clinics. Limited demographic and health status characteristics of patients were presented. Measurement of smoking status was obtained by self-report at four observation points and confirmed by serum thiocyanate tests at weeks and postpartum. The intervention process was well described including its theoretical basis and content. No information about length of patient counseling sessions was provided. Study 9 O'Connor, 1992 This study compared usual care nurse advice to quit and one formal class in self-help cessation methods with a 20 min one-to-one risk counseling and instruction in self-help methods among pregnant smokers in an Ottawa, Ontario hospital. This study translated and adapted A Pregnant Woman's Guide to Quit Smoking (1991) for French and English speaking Canadian pregnant smokers. The study had multiple methodological strengths including an design, sufficient sample size and a detailed description of a tailored intervention. Baseline equivalence on demographic, health and smoking characteristics was documented. Comparable data were not presented on those patients who refused. Urinary cotinine was used to confirm self-reported cessation. Patients lost to follow-up were not included in the calculation of quit rates. Using patients lost to follow-up in a recalculation of quit rates did not change the study results. Study 10 Price, 1992 An design evaluated the efficacy of a two-video (6 and 4 min) educational component, a brief counseling component, the use of the ALA Freedom From Smoking for You and Your Baby self-help component, and usual care physician advice in inner-city public health maternity clinics. Sample size estimates were based on a 40% expected quit rate in the videotape group. While mean age and racial composition were described, age, EGA, parity, race and education were not. Self-reports of smoking status were confirmed by carbon monoxide at baseline and end of pregnancy. Patients lost to follow-up were not used to derive quit rates. Although the intervention was tailored to pregnancy, no description of the intensity and duration of the counseling sessions following the videotapes was presented. The C group protocol was not standardized with patients receiving whatever smoking cessation advice, if any, their physicians typically provided. Study 11 Rush, 1992 A quasi- design evaluated the efficacy of brief, regular home-based individualized counseling delivered by a psychologist to pregnant smokers in England. The study had sufficient sample size to statistically confirm quit rates. Data on E versus C group equivalence and refusals were not provided. The results were reported for all subjects and a subset of those who smoked five or more cigarettes per day at baseline. Although information on education level was missing, descriptive characteristics of these patients were more comprehensive than for the overall E and C groups. Only self-reported end-of-pregnancy cessation was presented. Carbon monoxide and serum thiocyanate were used to analyze smoking status but not to confirm self-reports. Information about the nature, intensity, duration and specific content of the one-to-one counseling was limited. No description of the C group protocol was presented. Study 12 Peterson, 1992 An and a quasi- design were used to evaluate this study. Usual care of providing patients with a list of community-based smoking cessation resources was compared with a self-help program consisting of Freedom From Smoking for You and Your Baby plus audio tape and the same self-help program plus clinician 426

9 A meta-evaluation of smoking cessation counseling and reinforcement. A good description of study participants was provided indicating equivalence of the E) and C groups. A second intervention group (E2) was established by using all pregnant or spontaneous quitters at a fourth nonrandomized study site. The Ej group was not equivalent at baseline to the E, and C group. The sample size for each study group was very small (smokers n = patients and spontaneous quitters n = patients). A large selection bias was evident. Only one-half of all quitters were randomly selected to have a urine cotinine test. Patients lost to follow-up were not included in the calculation of quit rates. Although intervention methods were well described, no information was presented about the length of clinician counseling. Study 13 King, 1992 This study used a quasi- design to evaluate a new self help guide entitled 'Stop Now for Your Baby' and patient counseling methods for prenatal patients in the MCH program of the Pennsylvania Department of Public Health. Data were collected prior to implementation of the new program to establish an historical comparison (Q group. Of 1351 smokers, 911 E group had a phone and were considered eligible for inclusion in the program 'effectiveness' study. Only 60% of the E group patients were followed-up. Self-reported data only were used because they were considered by investigators to be adequate and biochemical verification unnecessary. The comparability of the E and C group was not adequately described. Because deception rates of 30 to 50% among pregnant women were well documented, self reports among these patients are not valid. Although a 25% quit rate was observed, the report acknowledged that only 13% of these patients quit after entering prenatal care. Assuming a 30% deception rate in the self reports, and including the 350+ patients lost to follow-up not used to calculate their quit rate, the true E group quit rate was 5%, not 13%. The self-reported C group quit rates ranged from 9 to 12% (average 10.7%). The true C group quit rate was 5%, assuming a 30% deception rate and a confirmed 30% patients lost to follow-up rate. The substantial number of patients lost to follow-up, the lack of biochemical testing and selection biases invalidate the results and conclusions of this study. Study 14 Windsor, 1993 An design was used to determine efficacy of a multi-component intervention of 10 min risk counseling session by a health educator, self-help guide (A Pregnant Woman's Guide to Quit Smoking, 1991), clinic reinforcement by the medical staff and social support. The study was conducted at multiple Birmingham, Alabama public health maternity clinics. A usual care C group received routine advice to quit and two antismoking pamphlets. Pre-study methods were used to estimate sample size needs. Multiple demographic, health status and psychosocial variables documented baseline patient population and refusals' equivalence. Self-reports were verified by saliva cotinine at baseline, midpregnancy and end of pregnancy. Patients lost to follow-up were counted as smokers. A process evaluation confirmed a high level of intervention exposure. The intervention was tailored for pregnant women and was pilot tested in a 1 year pre-trial formative evaluation. An added feature was the presentation of estimates of the impact of the intervention on the incidence of smoking attributable low birthweight and associated health care costs demonstrating the cost-benefit of the intervention, if disseminated statewide. A complete description of intervention methods was presented. Study 15 Seeker-Walker, 1994 This study used a randomized design to evaluate the added effect of individualized smoking cessation counseling delivered by a physician or nurse midwife with usual care anti-smoking advice among pregnant smokers in a mixed private/public prenatal clinic. A representative sample of pregnant smokers (n = 804), hypothesized quit rates (E = 20% and C = 10%) and sample size estimates were presented. A thorough description of eligible patients and non-participants was provided. Selfreports of smoking status were verified by urine 427

10 R. A. Windsor et al. cotinine tests. No E versus C group differences were observed for the intervention, although postpartum self-reported quit rates were significantly higher among the E group public health patients versus C group public patients. The intervention's theoretical basis, content and duration were well described, although counseling session length was not presented. Study 16 Valbo, 1994 An design tested the efficacy of selfhelp methods versus usual care among pregnant heavy smokers (5*10 CPD) in an Oslo, Norway hospital. The investigators used a translation and adaptation of A Pregnant Woman's Guide to Quit Smoking (1991) with their Ei group. The usual care C group received no intervention. Baseline equivalence of study groups was well documented. The E group quit rate was 20% and C group was 4%. Although smoking status from self-reports at follow-up was not biochemically confirmed, a key informant was present at the 32nd week sonogram when patient smoking status was assessed. This was a strong study, demonstrating the utility of using efficacious methods to create an intervention. It was unique by having heavy smokers only as study subjects. Intervention methods were well described, although the length of patient counseling session was not presented. This study was a followup study to the Valbo and Schioldborg (1994) study in which they also used the Guide with all types of pregnant smokers: E group = 12% and C = 4%. Study 17 Kendrick, 1995 The CDC-SCIP study evaluated the effect of low intensity materials delivered in routine care on smoking cessation in prenatal or WIC clinics in Colorado, Maryland and Missouri. A randomized design using the clinic as the unit of analysis was used. In each state approximately 2000 women were recruited. Representativeness of cohorts, however, was not documented. Levels of patient recruitment varied at each site and information was not presented describing patients or percentage who refused to participate or percent who were lost to follow-up. Self-reports of smoking status were verified by urinary cotinine at baseline, month 8 and postpartum. The E and C group quit rates were incorrectly calculated. Patient deception/nondisclosure (above 50%) reduced the quit rates by almost one-half in the E group and by approximately one-third in the C group. The intervention was tailored for pregnant women by focus groups and pre-testing of drafts of the materials. However, no information was provided about the content of the C group methods. It was concluded that the intervention lacked sufficient intensity to be effective. A lack of complete intervention delivery by project staff and the delivery of intervention materials to some control subjects was reported. Study 18 Lillington, 1995 This study used a quasi- design among four WIC clinics to evaluate the effectiveness of a 'Time for a Change: A Program for Healthy Moms and Babies' program in Los Angeles, CA. A number of serious methodological problems are apparent in this evaluation. The authors do not present data comparing the E andc_ groups for smokers only; current smokers and ex-smokers are grouped and aggregate demographic data are presented. A serious selection bias is apparent and simply matching only four sites does not establish equivalence at baseline. The authors incorrectly used methods from a study by Velicer (1992) to recompute quit rates based on a subsample of patients for whom cotinine analyses were not available. This method and the use of smoking self-reports is unacceptable with pregnant smokers. A severe memodological problem was only collecting self-reports on patients. This issue had been addressed in several publications prior to the conduct of this study. Among the original number of 225 patients, 6 weeks postpartum follow-up was only available for only 37 baseline smokers, an 85% loss to follow-up rate. Collecting postpartum self-reports to evaluate the behavioral impact of a smoking cessation intervention during pregnancy is unacceptable. In addition, of the few followed up, 30% of the patients refused. Of the samples collected (37 baseline smokers) a deception rate 428

11 A meta-evaluation of smoking cessation of 23% was confirmed. The combined effects of serious selection biases, absence of biochemical testing, an 85% attrition rate and a 23% deception rate results in recalculated quit rates for E and C patients of approximately 12% or less. The intervention was well-described, and appeared to be tailored to the population of African-American and Hispanic patients. It appeared to be perceived in a positive way by patients and staff. All study results and conclusions, however, about the efficacy of the patient education methods, are misleading and invalid. Study 19 Hartmann, 1996 An design and breath carbon monoxide measurements were applied to evaluate the effectiveness of brief OB/GYN resident-delivered patient education methods to pregnant smokers. A Pregnant Woman's Guide to Quit Smoking (1991) and systematic physician reinforcements, including follow-up letters, a chart reminder system and volunteer telephone counseling, were provided to E group patients. The C group received usual care quit smoking advice. Baseline E versus C group equivalence was confirmed. This was a strong study that confirmed an E group quit rate of 20% and a C group quit rate of 10%. The intervention also produced large significant reduction rates. This study is the first methodologically rigorous evaluation of the efficacy of physician-delivered behavior change methods to pregnant smokers. While the intervention was well described, the duration (minutes) of patient counseling sessions by residents was not reported and usual care C group methods were not presented. Study 20 Gielen, 1997 This study examined the efficacy of a multi-component intervention of risk counseling, A Pregnant Woman's Guide to Quit Smoking (1991), clinic reinforcement, and social support delivered by a peer educator in an inner-city urban hospital: Johns Hopkins University Hospital. Methodological issues such as statistical power, recruitment, measurement and a replicable intervention were addressed. E versus C group baseline equivalence was documented. No end of pregnancy quit rate differences were observed between the E group or C group. Measurement was based on self-report at baseline, end of pregnancy, 3 months postpartum and 6 months postpartum, with saliva cotinine validation at baseline and end of pregnancy. Although ineffective, the use of a peer educator to deliver the new patient intervention was a unique approach. Study 21 Walsh, 1997 This study used a randomized design and urinary cotinine tests plus patient self-reports to evaluate effectiveness. The intervention provided to the E group included physician/nurse midwife professional advice, a 14 min video, a 10 min counseling session and a self-help manual. C group patients were informed by health care providers that smoking was an important risk factor affecting infants and maternal health, and were encouraged to stop smoking and received a risk pamphlet. C group patients following randomization were compared on 12 demographic obstetrical and smoking-related variables. E versus C group equivalence was established. E group patients exhibited a significantly higher rate of cessation, 15% versus the C group patients at mid-pregnancy, 3%. This is a very strong study documenting the effectiveness of physician/nurse midwife delivered behavior change methods for pregnant smokers. Study 22 Lowe, 1998 This project used an design and biochemical confirmation to document the effectiveness of tailored smoking cessation methods for pregnant smokers in Brisbane, Australia. Data on group equivalence are presented. Following a preliminary study which documented the need to tailor methods to this population, a magazinestyle cessation booklet was developed for pregnant smokers in this setting. The E group had a confirmed 9% quit rate and the C group a 0% quit rate corroborated by urinary cotinine tests. An excellent process evaluation is reported. This was a very strong study documenting the efficacy of a 15 min one-to-one motivational counseling cessa- 429

12 R. A. Windsor et al. tion by a nurse midwife in combination with a tailored self-help booklet. Study 23 Gebauer, 1998 This study used a quasi- design to evaluate the effectiveness of advanced nurse practitioner delivered methods to pregnant smokers. The Q group consisted of 94 eligible pregnant smokers who enrolled in the prenatal clinic during 12 month period April 1993 to March The E group of 84 patients was recruited from April 1994 to March The baseline equivalence of the C and E groups was established. All participants received the same care by the same nurse-managed practitioners. The intervention included a 15 min oneto-one counseling session by the nurse practitioner who strongly advised the patient to quit and provided cessation assistance using A Pregnant Woman's Guide to Quit Smoking (1991). At 7-10 days after the intervention, a second contact was made by the nurse practitioner by telephone to discuss cessation efforts and to provide support. C group and E group patients were assessed typically between 6 and 12 weeks after receiving their baseline assessment. Cotinine-validated cessation rates confirmed a significant difference between the E group = 15.5% versus the Q group = 0%. The study is an excellent example of how a quasi design can be applied to evaluate the effectiveness of nurse-delivered behavior change methods for pregnant smokers. Methodological ratings of published research Individual and total ratings for each methodological criterion for the 23 studies evaluated in this ME appear in Table IV. The two senior authors independently and then jointly reviewed all studies that were candidates for inclusion in this ME. The total number selected was the same. The criteria applied were very specific and had been used by senior authors in two published reviews (Windsor and Orleans, 1986; Boyd and Windsor, 1993). There was no disagreement about what studies to include or individual study ratings for each criteria. This ME found that 11 studies achieved an overall rating score of very good: 18 or higher (nos 4, 8, 9, 12, 14, 15, 19, 20, 21, 22 and 23). Only two studies (Sexton and Hebel, 1984; Windsor et al, 1985) scored 17 points or higher in the first ME (Windsor and Orleans, 1986). In comparison with the first ME, substantial improvement was observed in each criterion area except measurement. A discussion of the salient points in this area of research and their implications for future research follows. Interventions Discussion Twelve studies (nos 4, 6, 8, 9, 14, 15, 16, 19, 20, 21, 22 and 23) provided excellent descriptions of intervention methods. Future research reports must make a description of the intervention process (time-frequency-process) a priority. Descriptions should include: (1) counseling content, (2) theoretical framework from which the cessation methods were derived, (3) duration of each patient contact and (4) frequency of application of each intervention component. The training of the intervention counselor should also be described. A thorough presentation of these components is important for two reasons. First, it enables researchers designing new investigations to learn from successes and failures. Second, it helps providers determine whether successfully applied interventions will translate to the practice setting. Detailed descriptions of cost, personnel and non-personnel, will also help to determine whether adoption for routine use by a new practice environment is financially feasible. Only three studies performed a cost analysis (Windsor et al, 1988, 1993b; Ershoff et al., 1989). Studies by Ershoff et al. (1989), Hjalmarson et al. (1991), O'Connor et al. (1992), Windsor et al. (1993), Valbo and Nylander (1994) and Lowe et al. (1998) demonstrated that tailoring of intervention methods was important to achieve behavioral impact. Process evaluation data in these studies, including focus group discussion and 430

13 A meta-evaluation of smoking cessation Ikble IV. Methodological ratings of or quasi- evaluation research for pregnant smokers Principal investigator (year) 1 Design 2 Sample 3 Description 4 5 Measurement Methods Rating score 1 Lilley (1986) 2 McArthur(1987) 3 Gillies (1988) 4 Ershoff (1989) 5 Messimer (1989) 6 Mayer (1990) 7 Haddow (1991) 8 Hjalmarson (1991) 9 O'Connor (1992) 10 Price (1992) 11 Rush (1992) 12 Peterson (1992) 13 King (1992) 14 Windsor (1993) 15 Seeker-Walker (1994) 16 Valbo (1994) 17 Kendrick (1995) 18 Lillington (1995) 19 Hartmann (1996) 20 Gielen (1997) 21 Walsh (1997) 22 Lowe (1998) 23 Gebauer (1998) Range patient consultation, indicated tailoring to the barriers to behavioral change and concerns of pregnant women led to greater overall acceptance, higher patient rating, and use of the methods than more generic strategies. Patient characteristics Unfortunately, many studies provided limited descriptions of their population demographic, behavioral and health characteristics. A comprehensive discussion of patient characteristics, especially participants who dropout and refuse, is essential to estimate study cohort representativeness and selection bias when reporting results. In many studies it was unclear to what populations their cohort results could be generalized. Process and compliance evaluation Another disappointing finding was the near absence of process evaluation data, documentation of the degree of patient exposure to health education intervention components. MacArthur et al. (1987) and Kendrick et al. (1995) reported low intervention exposure rate and little behavioral impact is a good example of what happens when patients do not receive an intervention. Data on the level of exposure to each intervention component delivered to patients is critical to make a conclusion about behavioral efficacy and internal validity. Data on patient compliance, the number and percent of methods completed by the patients, is critical to document. While these data may not always be easy to obtain, this type of assessment must be a priority so cause and effect relationships (efficacy) may be supported, if statistically significant E group versus C group differences are observed. Because of the salience of process evaluation in future intervention research, we advocate a new ME criterion process evaluation. The rating variables for Criterion 6 are presented in appendix Table AVI. 431

14 R. A. Windsor et al. Predictors of behavior change Too little data exists on predictors of smoking cessation during pregnancy. Research by Cnattingius et al. (1992) documented demographic predictors of quitting among pregnant smokers who quit on their own. Their findings indicated that White, married, young and educated pregnant smokers were more likely to quit without the aid of an intervention. Other research (USDHHS, 1990) documented that women who receive private prenatal care smoked fewer than 10 cigarettes per day, started smoking later in life and were not exposed to environmental household smoke were likely to quit during pregnancy. While these data are useful, they are based primarily on White women. Only one study was identified that examined predictors of cessation among pregnant smokers exposed to a smoking cessation intervention. Davis et al. (unpublished) studied predictors of cessation among African-American pregnant smokers in the Birmingham Trial II (Windsor et al, 1993) and the Smoke-Free Moms Study in Baltimore, Maryland (Gielen et al, 1997). Logistic regression analyses revealed different predictors of cessation and reduction for these two groups of women. The only common predictor between the two groups was being a light smoker (below 100 ng/ml baseline saliva cotinine). Although this study provided some insight, a thorough study of psychosocial predictors of cessation among pregnant women is lacking. In designing predictors or correlates of a smoking cessation study, patients are the minimum number required to conduct a rigorous analysis. If subgroup analyses are planned, e.g. comparisons by age, ethnicity/race and parity, at least 1000 patients would be needed to determine differences in subgroup quit rates such as those reported in the Birmingham Trial II (Windsor et al, 1993) where the Black E group quit rate (18.5%) was almost twice that of White E group (10.0%). Measurement Poor measurement (self-report only) was the greatest threat to internal validity of this ME. While additional resources are needed to collect and analyze biochemical samples, all self-reports must be confirmed by some type of cotinine test. Another major methodological issue was the consistently inaccurate calculation of quit rates. Multiple studies (Lilley, 1986; MacArthur, 1987; Gillies, 1988; Messimer, 1989; Haddow, 1991; Price, 1991, King, 1992; Lillington, 1995) failed to include patients lost to follow-up in their denominator to calculate end of pregnancy quit rates. This produces inflated quit rates in all studies. All patients assigned to an evaluation study group (eligible for follow-up) must be included in the denominator. In calculating the quit rate, Windsor and Orleans in 1986 recommended that smoking status be measured from a self-report and a biochemical test value for all study patients at baseline, mid-pregnancy and end of pregnancy. Patients lost to follow-up and patients for whom no biochemical test values are obtained must be classified as smokers. Patient deception Another issue related to the confirmation of quit rates is the degree of deception/non-disclosure in patient self-reports of smoking status. While population surveys of smoking status among adults have noted that self-reports may be valid without biochemical confirmation (Wagenknecht et al, 1990; Velicer et al, 1992), this conclusion is not true for smoking cessation studies among pregnant women. All cessation studies carry some risk of deception (Weissfield et al, 1989) because exposure to an E group protocol increases the social desirability of reporting abstinence. Societal pressure for pregnant women to not smoke strongly influences the self-reports of smoking status for both E and C group patients. Only two studies assessed deception rates, reporting them to be as high as 30% (Windsor et al, 1993) to 50% (Kendrick et al, 1995). Studies that use only selfreports of quit rates should be assumed to reflect substantial smoking non-disclosure. Future observational and evaluation studies of pregnant smokers must assess smoking non-disclosure. If a biochemical test is not performed, self-reported quit rates among the both the E and C groups non-disclosure will in most cases not be the same in the E and C 432

15 A meta-evaluation of smoking cessation groups, and should be reduced by predetermined rates to adjust for patient deception. At least a 25% deception rate must be used in the adjustment of published self-report data. Haddow et al. (1991) used serum cotinine as the sole measure to determine smoking status. Research by Windsor et al. (1993), Gielen Faden et al. (1997), Boyd et al. (unpublished) and Etzel's (1990) comprehensive review of the literature, however, noted that a biochemical test may not be the gold standard, especially if low levels of smoking and/or high amounts of environmental smoke exposure are present. Some research has shown that race (Wagenknecht et al, 1990) and age (Swan et al., 1993) may change the rate of nicotine metabolism. No study has determined whether pregnancy alters nicotine metabolism. Thus, until the measurement science is more precise, self-reports and a biochemical test must be used to document smoking status during pregnancy. Significant reduction A new issue in measurement of behavioral impact is the estimation of 'significant' reduction rates of cigarette smoke exposure. Four studies (Windsor et al, 1993, 1985 Hartmann et al, 1996; Gielen et al, 1997) defined significant reduction as a biochemically validated reduction in the amount of active cigarette smoke exposure to 30% or greater with saliva thiocyanate (Windsor et al, 1985), a 50% or greater reduction with saliva cotinine (Windsor et al, 1993; Gielen et al, 1997) or a 50% or greater reduction of CO (Hartmann et al, 1996) from the baseline biochemical measure. Analysis of saliva cotinine reduction data (Li et al, 1993) revealed that the patients who reduced their baseline smoking exposure levels 50% or more had infants whose birthweights averaged 92 g heavier than the patient group who did not change their smoking behavior. Quitters had infants whose birthweight averaged 250 g heavier than those who continued smoking at their baseline rate. The assessment of a 'significant' reduction rate of 50% less than a baseline value by a biochemical test, preferably cotinine analyses, is recommended in future studies (Windsor et al, 1998). Patient relapse In addition to the limited information about predictors of smoking cessation among pregnant women, little intervention research in relapse prevention during pregnancy and postpartum relapse has been conducted. Research (Fingerhut et al, 1990; Quinn et al, 1991; Windsor et al, 1993) has indicated that spontaneous quit rates (women who quit upon learning of their pregnancy) have ranged from 15 to 42%. Historically, clinicians have viewed these women as nonsmokers and have not monitored their smoking behavior during pregnancy. However, relapse prevention methods for spontaneous quitters might be at least as cost-effective as attempts to increase the quit rate of intake smokers. The impact of not providing relapse prevention strategies can be estimated by calculating the number of spontaneous quitters who relapse compared to the effectiveness of programs for intake smokers. The following is a brief discussion of this topic. Based on national surveys and clinical trials, a representative cross-section of 100 pre-pregnancy smokers might yield 33 spontaneous quitters a spontaneous quit rate of 33%. Assuming a 25% relapse rate, eight would relapse prior to delivery. Of the 67 pre-pregnancy smokers, 9% (six of 67) might quit early in pregnancy and maintain cessation to delivery with the advice to stop smoking from prenatal clinicians. Typical prenatal cessation interventions for Medicaid patients might increase the quit rate among intake smokers to 15% (10 of 67). These women would quit smoking early in pregnancy without relapse before delivery. A prenatal smoking intervention targeting intake smokers might generate four additional quitters. A moderately successful relapse prevention program might reduce relapse rates from 25 to 12.5%. This might yield four more pregnant women who maintain cessation. A typical intervention would have to achieve a 21% quit rate to generate four additional quitters among intake smokers. Given this added potential, smoking relapse prevention research during pregnancy is needed. 433

16 R. A. Windsor et al. Postpartum relapse Available data (Ershoff et al, 1989; Gielen et al, 1997) confirm that relapse is very high with intake smokers who quit during pregnancy, especially in public health populations. Questions about how and when to intervene with patients who quit smoking before and/or during pregnancy and among patients who were program failures exists. Although difficult to implement, postpartum interventions should begin after delivery and continue with pediatrician-nurse involvement at well-baby visits. Self-reports of smoking status in combination with biochemical tests should be used to establish abstinence and/or cessation during infancy. Infant urine samples can be collected and analyzed to document environmental tobacco smoke exposure. A follow-up should be conducted at least during the first 3 months of the postpartum period. Implications for future research Self-help minimal contact interventions have produced behavioral impact in public health maternity clinics (Windsor et al, 1985, 1993; Mayer et al, 1990) obstetrical care in the US (Hartmann et al., 1996) and non-us countries (Hjalmarson et.al, 1991; O'Connor et al, 1992; Valbo and Nylander, 1994; Valbo and Schioldborg, 1994; Walsh et al, 1997; Lowe et al., 1998), and at an HMO (Ershoff et al, 1989). These methods have been shown to be cost-effective (Ershoff et al, 1989; Windsor et al, 1988, 1993), easy to implement and could reach a larger segment of the smoking population than other strategies, e.g. group intervention. Shiffman (1993) has argued that research on innovative smoking cessation treatments is stagnant and that new approaches should be investigated. Research is needed to increase the efficacy of self-help minimal contact methods for pregnant smokers. More detailed measurement and patient compliance studies would be important additions to our knowledge base. More insight is also needed about the routine use of cessation methods in obstetrical care by physicians. Only three studies (Messimer et al, 1989; Valbo and Nylander, 1994; Valbo and Schioldborg, 1994; Hartmann et al, 1996) in this review were implemented among physicians. The Messimer et al (1990) study, due to methodological weaknesses, was inconclusive, while the Hartmann et al. (1996) investigation demonstrated significant impact. An essential area for future study is the evaluation of the 'effectiveness' of methods in public health practice. Almost all research reviewed in this ME were 'efficacy' studies. Trained health educators/counselors delivered the interventions under optimal conditions to achieve optimal results. In prenatal care practice, physicians, nutritionists, nurses or social workers would be the providers of the intervention as a part of their daily routine. Other than the unsuccessful SCIP study (Kendrick et al, 1995), little information is available about the effectiveness of minimal contact methods under typical clinical practice conditions. The Healthy People 2000 objectives for the nation (USDHHS, 1991) identifies a goal of a 10% smoking prevalence rate for pregnant women. Windsor et al. (1993a) have estimated the impact of the dissemination of tested cessation methods on the US birth cohort (over 4 million per year) for the decade of the 1990s. They concluded that even in the event of full, nationwide dissemination of available cessation methods, the most likely result in the Year 2000 would be a smoking prevalence of 15% or less rather than the targeted 10%. Targeting other subgroups of women of childbearing age other than public/private obstetrical patients is needed to achieve a smoking prevalence of 10%. Only when all groups of female smokers of childbearing age are being routinely reached will the possibility of achieving the Year 2000 smoking prevalence objective (USDHHS, 1991) be translated to a probability. Future evaluation research is needed to determine barriers to dissemination, diffusion and adoption at multiple settings and among large, welldefined populations in managed care or WIC programs. Application of the insight derived from this ME should enhance the achievement of national and local goals and improve the science 434

17 A meta-evaluation of smoking cessation and art of health education methods for pregnant women, new mothers and new fathers. Acknowledgements The authors would like to thank Dianne C. Barker, MHS, Consultant, and Nancy J. Kaufman, RN, MS, the Robert Wood Johnson Foundation, for their assistance in reviewing and editing a draft of this manuscript. References Boyd, N. R. and Windsor, R. A. (1993) A meta evaluation of nutrition education intervention research among pregnant women. Health Education Quarterly, 20, Butler, N., Goldstein, H. and Ross, E. (1972) Cigarette smoking in pregnancy: its influence on birth weight and perinatal mortality. British MedicalJoumaI,\i, Cnattingius, S., Lindmark, G. and Meirik, O. (1992) Who continues to smoke while pregnant? Journal of Epidemiology and Community Health, 46, Ershoff, D. H., Mullen, P. D. and Quinn, V. P. (1989) A randomized trial of a serialized self-help smoking cessation program for pregnant women in an HMO. 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