A MULTICENTER STUDY OF HOSPITALIZATION IN RHEUMATOID ARTHRITIS

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1 6 4 A MULTICENTER STUDY OF HOSPITALIZATION IN RHEUMATOID ARTHRITIS Frequency, Medical-Surgical Admissions, and Charges FREDERICK WOLFE, SUE M. KLEINHEKSEL, PATRICIA W. SPITZ, DEBORAH P. LUBECK, JAMES F. FRIES, DONALD Y. YOUNG, DONALD MITCHELL, and SANFORD ROTH During 98, 23 of 86 patients (5.%) with rheumatoid arthritis were hospitalized 60 times because of the disease. The mean length of hospitalization was 3. days, and the cost $7,845. Surgery accounted for 54.4% of admissions, but 69.2% of costs. The average cost for total joint surgery was $2,287. Most medical admissions (46.6 %) were for the diagnosis or treatment of articular disease, but 42.5% were for treatment of side effects of therapy, and.0% for complications of RA. The most commonly performed surgical procedures included reconstructive surgery of the hand/wrist (n = 35) and foot (n = 22), followed by total knee replacement (n = 8). Previous studies have suggested that hospitalization may account for as much as 66% of direct medical costs for individuals who have stage 3 rheumatoid arthritis (RA) (). In addition, hospitalization serves as a measure of morbidity, both of disease (as, for example, when total joint replacement is required for joint destruction by RA), and of side effects of From the Wichita Arthritis Center and the University of Kansas, Wichita; the Department of Medicine, Stanford University School of Medicine, Stanford, California; the University of Saskatchewan, Saskatoon, Saskatchewan, Canada; and The Arthritis Center, Ltd., Phoenix, Arizona. Supported by grants from the SmithKline Corporation and the National Institute of Arthritis, Diabetes, and Digestive and Kidney Diseases (AM-2393) to the American Rheumatism Association kledical Information System. Frederick Wolfe, MD; Sue M. Kleinheksel, OTR; Patricia W. Spitz, RN, MS; Deborah P. Lubeck, PhD; James F. Fries, MD; Donald Y. Young, PhD; Donald Mitchell, MD; Sanford Roth, MD. Address reprint requests to Frederick Wolfe, MD, the Wichita Arthritis Center, 035 N. Emporia, No. 230, Wichita, KS Submitted for publication May 8, 985; accepted in revised form October 29, 985. therapy, such as when a posterior subcapsular cataract is resected or drug-induced gastritis is treated. Although hospitalization is a relatively common event for the RA patient, little is known about the risks of hospitalization, the actual costs, the reasons for hospitalization, and, in the case of admissions for surgery, the type and frequency of procedures performed. To secure further information on hospitalization for rheumatoid arthritis, a cohort of 86 RA patients seen in Canada and the United States was followed prospectively, beginning in 98. In this study, we report on hospitalizations for this cohort during 98. PATIENTS AND METHODS Patients. In 98, we began a prospective study of outcomes in rheumatoid arthritis utilizing information on patients enrolled in the American Rheumatism Association Medical Information System (ARAMIS) databanks in Phoenix, AZ; Saskatoon, Canada; Palo Alto, CA; and Wichita, KS (2). Patients participating in this study agreed to complete detailed self-administered questionnaires concerning their disease, to supply financial information dealing with medical costs, and to allow the investigators to contact physicians and other providers to obtain medical and cost information. Patients were free to not answer any question, and clinic attendance was not required at any center. A signed informed consent form was required for participation in the study. Except at Stanford, where patients had been recruited previously, each center was requested to compile a list of RA patients from their databank records for possible inclusion in the study. As a minimum, all patients seen within the previous 2 years were included in this list. In addition, individual centers could recruit patients seen before the 2-year period, if the databank director felt such recruitment might be successful. Potentially eligible patients were screened so that at Arthritis and Rheumatism, Vol. 29, No. 5 (May 986)

2 HOSPITALIZATION IN RA 65 entry all patients had definite or classic RA as defined by the American Rheumatism Association (3); were receiving 5 0 mg of prednisone; were not receiving immunosuppressive drugs; were judged capable of completing the questionnaires; were not in RA functional class IV (4); and were not participants in other nonobservational study protocols (for example, drug trials). Patients who participated in the Stanford Outcome in Rheumatoid Arthritis (ORA) study were recruited directly from the northern California community of RA patients in 978, and were followed only by the Stanford databank investigators until 98, when the patients were enrolled in this study. No patients were excluded from the study becaue of failure to meet entry criteria, and 37 of 323 of them completed the study year. Patients were not necessarily being treated by physicians at Stanford University. Twenty percent of ORA patients were enrolled in prepaid health plans. Patients followed at the Phoenix and Wichita centers had been seen at least once by clinic physicians. These clinics are private practice, fee-for-service clinics. Twelve percent of the patients at the Phoenix center and I% of the patients at the Wichita center were enrolled in prepaid health plans. Two hundred forty-five patients eligible for the study were identified at the Phoenix center. Twenty-five patients had been excluded because of participation in a drug study, 2 patients were in functional class IV, was receiving cyto toxic drugs, and was receiving 0 mg of prednisonel day. Of the 245 who were eligible, 47 patients refused to participate, and 93 patients did not reply to the request for participation. Of the 05 patients who received the questionnaire, 9 completed the study year. Three hundred forty-eight eligible patients were identified at the Wichita databank. Two patients had been excluded because they were in functional class IV, I patient was excluded for taking cytotoxic drugs, and 4 were excluded for taking > 0 mg of prednisone/day. Seventy-six patients did not reply to requests for participation, 2 refused to participate, and 24 who had agreed to participate did not complete the study year. Patients followed at the Saskatoon center had been seen at least once by clinic rheumatologists at the University of Saskatchewan. In Saskatchewan, medical care is prepaid under a system of tax-supported, government-sponsored, health insurance. Seventy-five percent of RA patients in northern Saskatchewan have been seen at the Saskatoon center (5). Two hundred eighty eligible patients were identified by the Saskatoon center. One hundred eighteen patients were ineligible to participate: 76 patients were in functional class IV, 0 patients were receiving >I0 mg of predlnisone/day, 9 patients were receiving cytotoxic drugs, and 23 patients had more than of the above reasons for exclusion. Thirty patients were judged incapable of completing the questionnaires for reasons such as noncompliance, mental incompetence, or poor command of English. Of the patients eligible to participate, 48 refused and 34 did not respond to requests to participate. Twenty-six patients responded after the closure date of the study, but agreed to participate. They were enrolled in a later phase of the study, but are not included in this report. Of the 98 patients entered in the study, 72 completed the study year. Assessment methods. To assess the effect of RA, patients completed self-administered questionnaires in July 98 and January 982, regarding health care costs and utilization in the preceding 6 months, including the number and type of physician visits and hospital admisoions, and the charges for such services. In addition, information relating to function, self-reported pain, drug side effects, demographics, and mortality was requested (6). Function was measured using the Stanford Health Assessment Que\tionnaire (HAQ). This self-administered instrument assesses each of 8 activities of daily living (ADL) on a 0-3 scale: 0 = without difficulty, I = with some difficulty, 2 = with much difficulty (or with assistance), 3 = unable to perform. A disability index was obtained by adding the scores and dividing the sum by the number of ADL components answered. The disability index ranges between 0 and 3 on a continuous scale (7). Data concerning hospital charges and length of stay were obtained directly from the institutions records. Questionnaires were checked for completeness at the individual databank centers and for accuracy at the clinical centers (Phoenix, Saskatoon, and Wichita) by comparing patients questionnaire answers with the clinic records. Patients, physicians, clinics, and hospitals were contacted when it was necessary to obtain complete information on health service utilization and charges. To assess reporting accuracy for health services in the preceding 6 months, we validated random samples of patient self-reports by conducting chart reviews of medical records from physicians providing care. No differences in reporting were noted in these analyses utilizing paired t-tests and significance levels of Discharge summaries were obtained for all hospitalizations and were individually reviewed to determine if a hospitalization was arthritis-related. A hospitalization was considered non-arthritis-related when there was no known or postulated association between RA and the hospitalization diagnosis (e.g., appendectomy). Hospitalization classification. We classified only those admissions related to surgery of the musculoskeletal system as surgical hospitalizations. In addition, hospitalizations as a result of complications that related to these procedures (e.g., infected prosthesis) were counted as surgical hospitalizations. All other hospitalizations were considered medical. We classified a medical hospitalization as being for diagnosis and treatment when the dismissal summary and/or the hospital course indicated that as the primary reason for hospitalization. Hospitalizations were coded as complications of RA when they resulted from known RA complications. Specifically, we classified rheumatoid lung, ophthalmologic complications of RA (e.g., corneal abrasion or ulceration), leg ulcers, fractures with minimal trauma in non-steroid-treated patients, and joint infection (nonsurgical) as complications of RA. Classified as treatment side effects were: fractures judged unusual or premature in patients receiving long-term or high-dose corticosteroid therapy, gastrointestinal (GI) bleeding or acid peptic symptoms in patients receiving nonsteroidal antiinflammatory drug therapy, obliterative bronchiolitis in

3 66 WOLFE ET AL patients receiving penicillamine therapy who had sudden onset of dyspnea (8), posterior subcapsular cataract resection in patients who had received long-term or high-dose corticosteroid therapy, a rash temporally related to gold therapy, and other similar side effects. Statistical methods. In 98, there were 60 hospitalizations because of RA for 23 patients (29 patients from Phoenix, 28 patients from Saskatoon, 53 patients from northern California, and 50 patients from Wichita). All data from the Saskatoon and Wichita databanks were complete. Data on hospital charges were complete in 42 of 53 hospitalizations monitored in the Stanford ORA population, and in 28 of 29 hospitalizations in Phoenix. Physician and surgeon charges were missing in 23 of 53 hospitalizations in the Stanford ORA population and 4 of 29 hospitalizations in the Phaenix population. When these data were missing, a charge was imputed for the procedure, by calculating the mean charges per day for similar procedures where complete charge information was available from hospitalizations at that center (9). Hospital charges in this report represent the combined hospital and physician charges. In the Stanford ORA population, charge data from 4 hospitalizations were missing because of the refusal of prepaid health plans to release such information. In computing charges for services paid through public assistance programs (e.g., Medicaid and MediCal), we used the actual amount paid by the program as the charge for the services performed. Charges for hospitalizations in Canada were obtained from data supplied by the Saskatchewan Hospital Service Plan and the Medical Care Insurance Commission. To adjust for differences in the exchange rate between Canada and the United States in 98, we multiplied Canadian dollars by a factor of Nonparticipants. To determine if participants in the study differed from those who were eligible to participate but were not enrolled, we compared participants and nonparticipants at each center for the demographic and severity items noted in Table, utilizing t-tests and chi-square tests where appropriate. In these analyses, we used data available during 98, the date of the first study questionnaire. Data were available for all participants except those at the Stanford ORA, where the erythrocyte sedimentation rate (ESR) was not obtained and where data concerning rheumatoid factor were available for only 97 patients. When data were not available at this time point for nonparticipants, we used the last available datapoint. Overall, 68% of nonparticipants had data within 2 years of the beginning of the study, and 88% had data available within 3 years. The 2- and 3-year data availability, respectively, for the individual centers was: Wichita, 89% and 00%; Saskatoon, 45% and 84%; Phoenix, 68% and 83%; Stanford ORA, 00% and 00%. Nevertheless, this method of assessment probably underestimated the actual disability, severity, and duration of disease of nonparticipants since disability, disease progression, and drug therapy may have increased during the period when followup information was missing. Participants and nonparticipants in the Stanford ORA sample did not differ in any demographic or severity characteristics. Participants in Saskatoon had greater duration of disease (22.3 versus 9.4 years for nonparticipants; P = 0.022), and higher disability indexes (.43 versus.2; P = Table. Selected clinical and demographic characteristics of 86 rheumatoid arthritis patients* Age, years 56. (4.2) % male 24 Level of education, grade 2.5 (2.9) Disease duration, years 5.4 (.4) % patients under rheumatologist s care (98) 70 % patients under rheumatologist s care (ever) 9 % rheumatoid factor-positive 82 Westergren erythrocyte sedimentation rate 39.6 (22.3) (mdhour) % patients received Gold therapy 55 Penicillamine 30 Plaquenil 28 Prednisone 59 Disability index, (0.57) * Data available for 98. Unless otherwise indicated, values are means. Values in parentheses are the standard deviations ). At the Wichita center, participants had slightly higher disability indexes (.07 versus 0.90; P = 0.035), and more participants were taking prednisone (33% versus 22%; P = 0.048) and gold (22% versus 9%; P = 0.004). At the Phoenix center, 24% of the participants were male, and 37% of nonparticipants were male (P = 0.039). The disability index was higher in participants than nonparticipants (I.38 versus 0.96; P < 0.00), but the ESR was higher in nonparticipants than in participants (48.0 mm/hour versus 36.8 mm/hour; P = 0.004). Except for these differences, participants and nonparticipants were similar. We also compared Phoenix patients who were excluded because of drug study participation with participants in our study. Participants had higher disability indexes (.23 versus 0.9; P = 0.032), but were otherwise similar. RESULTS The clinical and demographic characteristics of patients in this study are reported in Table. The mean age of patients was 56. years. Disease was of long duration (5.4 years) and functional disability was moderate (disability index =.2). As was expected, most patients had been treated with gold (55%) and prednisone (59%). Fifteen percent of all patients who had rheumatoid arthritis were hospitalized during 98. Data in Table 2 show that arthritis-related surgery accounted for 54.4% of hospitalizations, while 45.6% of hospitalizations were for medical reasons. Multiple hospitalizations were not uncommon. In all, 23 patients underwent 60 hospitalizations or procedures (.3/hospitalized patient). The most common surgical procedures involved reconstructive surgery of the hands or feet, as noted in Table 3. Non-total joint surgery accounted for approximately 60% of surgical hospital-

4 ~ ~~ HOSPITALIZATION IN RA 67 Table 2. Hospitalizations for 23 rheumatoid arthritis (RA) patients during 98 Hospitalizations Hospital charges (98 dolars)t - Medical hospitalization No. % of all % of Mean % of % of hospitalizations category* f SD all category* Diagnosis and treatment ,594 f 4, Treatment side effects ,72 2 2, Complications of RA ,067 f 4, Total ,066 f 3, Surgical hospitalization (musculoskeletal surgery) Total joint surgery Knee 6$ 0.0 Hip Elbow Shoulder 0.6 Surgical complications Non-total joint surgery Total * Medical or surgical. t Includes physician and hospital charges. $ Includes 2 hospitalizations with bilateral knee surgery (no. total procedures = 8) ,287 f 5,89 4,50 f 7,04 9,234 f 2,633 2,49 2 2,070 7,450 2,039 f 6,672 4,608 f 2,834 7,680 f 5, izations and almost one-third of all hospital admissions. Total knee replacement was the most common total joint procedure, and was performed twice as often as total hip replacement (Tables 2 and 3). Diagnosis or treatment was the most common reason for medical hospitalization (45.6%), but treat- ment side effects were responsible for more than 42% of such admissions. GI side effects (acid peptic symptoms or GI bleeding) were the most common reasons for admission (9 patients), followed by fracture related to corticosteroid therapy and associated osteoporosis (4 patients) (Table 3). Two patients who had oblitera- Table 3. Reasons for hospitalizations for 23 rheumatoid arthritis (RA) patients during 98 Medical No. Surgical (musculoskeletal surgeries) No. Diagnosis and treatment Total joint Evaluation and treatment 29 Shoulder Rehabilitation 5 Elbow Knee Hip 4 8* 8 Treatment side effects Surgical complications Fracture 4 Joint fusion Gastrointestinal bleeding 4 Infected prosthesis Acid peptic symptoms 5 Total joint revision 4 Obliterative bronchiolitis Cataract Infection Skin Miscellaneous Complications of RA Fracture Pulmonary Infection Skin (ulcer) 6t 2 2 * Represents 6 hospitalizations. t Represents 2 patients. $ Sixty-five procedures during 52 hospitalizations. 2 6 Non-total joint surgery$ Hand/wrist arthroplasty with implant 24 Hand/wrist arthroplasty with s ynovectomy Foot synovectomy Carpal tunnel release 3 Foot arthroplasty 22 Nodule removal 3 Arthroscopy

5 6 8 WOLFE ET AL Table 4. Hospitalizations for 23 rheumatoid arthritis (RA) patients during 98 - No. Length of stay (mean -+ SD, days) Medical hospitalization Diagnosis and f 9.9 treatment Treatment side effects f 6.7 Complications of RA t 4.7 Surgical hospitalization (musculoskeletal surgery) Total joint surgery Knee Hip Elbow Shoulder Surgical complications Non-total joint surgery * f ? f f f 4.3 Total hospitalizations f 8.9 * Includes hospitalization of 2 patients for bilateral knee surgery (total no. of procedures = 8). tive bronchiolitis which was thought to be related to penicillamine therapy were hospitalized 6 times. Complications of RA were reported the least as reasons for medical hospitalization (.O%). These admissions were divided among fractures, pulmonary involvement, infection, and leg ulcers. Although the average length of stay was longer for medical hospitalization than for surgical hospitalization (.3 versus 9. days) (Table 4), surgical hospitalization was more expensive, averaging $l,045/day as opposed to $380/day (Table 2). Total knee replacement was the most costly surgical procedure ($4,50), followed by total elbow replacement ($2,49). Surgical admissions, responsible for 54.4% of hospitalizations, accounted for 69.2% of all hospital charges. Regional and databank variation in charges and hospitalization type, as well as the effect of disease severity on hospitalization, will be reported elsewhere (0). DISCUSSION The most important result of this study is the identification of the high rate of hospitalization in patients with rheumatoid arthritis, and the related high charges. More than 5% of RA patients were hospitalized during a -year period at a mean charge per patient of $7,845 (Table 5). When the charges associated with hospitalization were apportioned among the 86 patients at risk, the yearly cost of hospitalization approximated $,83 per patient. The expense of hospitalization was related primarily to surgery, regardless of the type. Although the charge for total joint replacement was high ($953/ day), non-total joint surgery was even more costly ($l,43/day). Non-total joint surgery was the most common reason for admission in our cohort, accounting for 32.5% of all admissions and 24.8% of all costs. In contrast, the charge for nonsurgical hospital stays averaged $380/day. An important corollary observation is that, while the mean length of stay for hospitalizations dependent on expensive surgical technologies fell within Medicare diagnosis-related group allowances, the mean length of stay for medical patients exceeded such allowances ( l). These data have important implications for health care planning and medical practice. The impact of treatment side effects on hospitalization rates has not been described previously. We noted that side effects were responsible for almost 43% of medical admissions. The most common reason for such admissions was the evaluation and treatment of gastrointestinal complaints. Corticosteroids, implicated in premature osteoporosis and fracture, and in subcapsular cataracts were important causes of medical hospitalization, as well. Side effects of treatment are frequently difficult to establish. In this study, we accepted the designation side effect when there was a well-known relationship between a symptom and a presumed offending agent, or when the attending physician specifically labeled the admission as related to a side effect. Nevertheless, the difficulty in establishing causal relationships suggests that side effect frequency should be interpreted cautiously. Iatrogenic side effects and toxicity have been proposed as important outcome dimensions in RA (2). In this cohort, the combination of medical side effects and surgical complications accounted for 23.3% of all hospital admissions. The significant number of admissions for such effects serves as an important reminder that our therapies are not always harmless or inexpensive. Table 5. Hospitalization data for rheumatoid arthritis in 98 This study USA Patients 86,532,700* Hospitalizations 60 Patients hospitalized 23 % hospitalized 5. Days hospitalized/patient 3. Mean cost ($ per patient) 7,845 Cost per patient at risk,83 Total cost ($) 964,993 ~~ ~ ~ ~~ * Rheumatoid arthritis prevalence estimated at I% (l6,7).

6 HOSPITALIZATION IN RA 69 The generalizability of data such as these depends on the extent to which these RA patients are typical. While there is no such thing as a prototypical RA patient, those in this study are similar in demographic and clinical characteristics to RA patients described in the rheumatologic literature (3). They are derived largely from community rather than university practices. Almost all patients (9.0%) had been seein by a rheumatologist at least once. Their care was not predicated upon rheumatologic management, however, since at 2 of the centers, 3443% of patients were not seen by rheumatologists for outpatient arthritis care during the study year, and only 43% of all hospital medical admissions were attended by rheumatologists. Patilents in this cohort had mild disease, as well as severe disease; some patients had inactive RA when they entered the study. Thus, our patients seemed typical both of patients described in the rheumatology literature and of those seen in the community by consultant rheumatologists. Additional confirmation for the data presented here comes from the recent report by Yelin et al (4), who studied 8 I I RA patients followed by rheurnatologists in northern California. Seventeen percent of their patients were hospitalized during a I-year period. Two-thirds of the hospitalizations in their cohort were for arthritis surgery (5). Cohorts of patients with definite or classic RA derived largely from rheumatologic practices, however, may differ significantly frorn RA patients seen by non-rheumatologists. Moreover, patients who participated in our study may have had slightly more severe disease than did the nonparticipants. We did not study patients in functional class IV, nor patients who received cytotoxic drugs or >I0 mg of prednisone/day. These patients had more severe RA than did the study participants, and may have had greater hospital utilization and medical expenses. Thus, we urge caution in extrapolating the data presented here directly to the community-at-large. Even so, our data suggest that the cost of RA hospitalization may be very large, considering the estimate of I.5 million patients with rheumatoid arthritis in the United States in 98 (Table 5). Results of this study and the report of Yelin et a (4) are further indications that our current technologies are expensive, and that ultimately, reduction in the cost of RA will follow discovery of more effective treatments than are currently available. ACKNOWLEDGMENTS We thank Dee Simpson, May Haga, Pat Krutzen, RN, and Janet Kaiser for their help in obtaining hospitaliza- tion and cost data at the various centers. We also thank Carolyn Shook for her invaluable secretarial skills. REFERENCES. Meenan RF, Yelin EH, Henke CJ, Curtis DL, Epstein WV: The costs of rheumatoid arthritis: a patientoriented study of chronic disease costs. Arthritis Rheum 2: , Fries JF: The chronic disease databank: first principles to future directions. J Hist Med Rehabil 9: 6-80, Ropes MW, Bennett GA, Cobb S, Jacox R, Jessar RA: 958 revision of diagnostic criteria for rheumatoid arthritis. Bull Rheum Dis 9:75-76, Steinbrocker 0, Traeger CH, Batterman RC: Therapeutic criteria in rheumatoid arthritis. JAMA 40: , Mitchell DM, Spitz PW, Young DY, Fries JF, Bloch D: Mortality in rheumatoid arthritis. In preparation 6. Lubeck DP, Spitz PW, Fries JF, Wolfe F, Mitchell DM, Roth SH: A multicenter study of annual health service utilization and costs in rheumatoid arthritis. Arthritis Rheum 29: , Fries JF, Spitz PW, Kraines RG, Holman HR: Measurement of patient outcome in arthritis. Arthritis Rheum , Wolfe F, Schurle DR, Lin JJ: Upper and lower airway disease in penicillamine treated patients with rheumatoid arthritis. J Rheumatol 0:406-40, US Bureau of Census: The current population survey, design and methodology. Technical paper 40. Washington, DC, US Government Printing Office, Wolfe F, Kleinheksel SM, Spitz PW, Lubeck DP, Fries JF, Young DY, Mitchell DM, Roth S: Hospitalization in rheumatoid arthritis: regional variations in utilization and costs. J Rheumatol (in press). Lockshin MD: DRG legislation and rheumatic disease. Bull Rheum Dis 34:l-5, Fries JF: Advances in assessing rheumatoid arthritis. Br J Rheumatol (suppl) 22:48-58, Harris ED: Rheumatoid arthritis: the clinical spectrum, Textbook of Rheumatology. Second edition. Edited by WN Kelley, ED Harris Jr, S Ruddy, CB Sledge. Philadelphia, WB Saunders, 985, pp Yelin EH, Henke CJ, Kramer JS, Nevitt M, Epstein W: A comparison of the treatment of rheumatoid arthritis in health maintenance organizations and fee-for-service practices. N Engl J Med 5: , Nevitt M, Yelin E, Epstein W: Surgery for RA: patient and MD practice characteristics (abstract). Arthritis Rheum (suppl) 27:S38, Hochberg MC: Epidemiology of rheumatoid arthritis in developed countries. J Rheumatol 0:7-0, Wolfe AM: The epidemiology of rheumatoid arthritis: a review. Bull Rheum Dis , 968