Diagnosis and Care of Irritable Bowel Syndrome in a Community-Based Population

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1 ... HEALTHCARE UTILIZATION... Diagnosis and Care of Irritable Bowel Syndrome in a Community-Based Population Barbara P. Yawn, MD, MSc; G. Richard Locke III, MD; Eva Lydick, PhD; Peter C. Wollan, PhD; Susan L. Bertram, RN, MSN; and Margary J. Kurland, RN Objective: To identify the healthcare utilization and evaluation in a community-based population with an incident diagnosis of irritable bowel syndrome (IBS). Study Design: Retrospective cohort. Patients: A randomly selected cohort of 149 Olmsted County, MN, adults with an incident diagnosis of IBS between June 1, 1992, and December 31, Methods: Retrospective medical record review of each medical encounter for the 10 years before and the 3 years after the incident IBS diagnosis. Specific attention was given to healthcare visits, tests, and treatment associated with documented gastrointestinal (GI) tract symptoms and diagnosis of IBS. Results: Of 149 patients, 98 (66%) were women, and the mean patient age was 46.6 years. Patients averaged 4.7 healthcare visits annually, including 0.5 related to GI tract symptoms. Two thirds of patients had GI tract symptom related visits at least 2 years before IBS diagnosis. Only 5% of IBS diagnoses were made by a gastroenterologist. Colon examinations (colonoscopy or barium enema) were performed on 47% of patients and were more common in those aged 55 years (58% vs 36%; P =.02). One third of patients had no GI tract testing proximal to the IBS diagnosis. Following the IBS diagnosis, only about half the patients made any IBS or GI tract symptom related visits per year. Conclusion: The path to diagnosis of IBS is through the primary care physician and includes minimal testing and limited follow-up care. (Am J Manag Care 2001;7: ) specialty clinic populations suggest that people with IBS are high users of gastrointestinal (GI) tract symptom related healthcare, yet most patients with IBS never visit a gastroenterologist. Therefore, it is likely that gastroenterology clinic based study results do not accurately reflect the demographic characteristics, diagnostic evaluation, or healthcare utilization of the population with IBS. Furthermore, studies that have been published from generalist practices seldom include the important prediagnostic period. This study retrospectively follows a randomly selected community-based cohort with new diagnoses of IBS between June 1, 1992, and December 31, 1994, to provide a description of the medical path to diagnosis of IBS. For each person in the cohort, all healthcare visits and documented GI tract symptom related visits and GI tract complaints in the 10 years before the incident diagnosis of IBS were identified and recorded. In addition, data were collected from the 3 years following the first IBS diagnosis. By assessing the patient s healthcare utilization during approximately 13 years, we are able to describe the care and evaluation pattern temporally associated with diagnosis of IBS. Irritable bowel syndrome (IBS) is a common and reportedly costly condition affecting 3% to 10% of American and European adults. 1-5 The diagnosis is based on the presence of a symptom complex and the exclusion of other causes. Definitive therapy is not currently available. Results of studies 6-13 based in From the Department of Research, Olmsted Medical Center, Rochester, MN (BPY, PCW, SLB, MJK); the Division of Epidemiology, SmithKline Beecham Pharmaceuticals, Collegeville, PA (EL); and the Gastroenterology Outcomes Research Unit, Mayo Clinic, Rochester, MN (GRL). This research was made possible by a grant from SmithKline Beecham Pharmaceuticals, Collegeville, PA. Address correspondence to: Barbara P. Yawn, MD, MSc, Director, Department of Research, Olmsted Medical Center, 210 Ninth Street SE, Rochester, MN yawnx002@tc.umn.edu. VOL. 7, NO. 6 THE AMERICAN JOURNAL OF MANAGED CARE 585

2 ... METHODS... Setting Olmsted County is a metropolitan statistical area 90 miles south of Minneapolis, MN. The population is estimated to be 92% non-hispanic white. 14 Olmsted County is a medically isolated community that has local resources for primary, tertiary, and quaternary care. Previous studies 14 estimate that more than 90% of all Olmsted County residents healthcare is delivered within Olmsted County by the Mayo Medical Center or the Olmsted Medical Center (both in Rochester, MN). Data Collection Using the database of the Rochester Epidemiology Project, 14,15 we identified all Olmsted County residents with a diagnosis of functional or irritable bowel syndrome (ICD-9 Code 564.1) or spastic colon psychogenic (ICD-9 Code 306.4) between June 1, 1992, and December 31, The Rochester Epidemiology Project links all patients to all medical records from all sources of medical care that each individual has used within the county. Broad criteria were used for the search to increase sensitivity at the risk of reducing specificity. This type of search strategy was possible because final patient selection relied on medical record review rather than on administrative data only. The initial search identified 1245 potential patients (a combination of incident and prevalent cases), of which 36 (2.9%) had previously refused general research... HEALTHCARE UTILIZATION... Table 1. Annualized Visits Not Related to Gastrointestinal Tract Symptoms *Percentage of patients who had any visits during the period. Not annualized for the diagnostic period. Visits, mean No. (%)* Period Age y Age y Age 55 y Women Men +2 y to +3 y 4.0 (97) 4.4 (98) 6.6 (98) 5.4 (99) 4.5 (95) +1 y to +2 y 4.4 (98) 3.8 (80) 5.2 (90) 5.0 (91) 3.4 (85) +30 d to +1 y 4.6 (91) 3.5 (82) 4.1 (78) 4.0 (85) 3.9 (78) -30 d to +30 d 1.2 (67) 1.3 (59) 1.2 (62) 1.1 (58) 1.5 (72) -30 d to -1 y 4.6 (87) 4.1 (73) 4.6 (87) 4.9 (85) 3.5 (76) -1 y to -2 y 4.2 (85) 4.2 (84) 4.1 (83) 4.3 (88) 3.9 (76) -2 y to -5 y 3.4 (97) 3.3 (98) 4.0 (96) 3.7 (98) 3.5 (96) -5 y to -10 y 2.6 (97) 2.6 (95) 2.8 (94) 3.0 (95) 2.0 (95) authorization for medical record review and thus could not be included in the study according to Minnesota statute. 16 The goal was to identify 150 patients for in-depth review. The number was selected to match available funding and nurse abstractor time for this extensive medical record review. The medical records of a random sample of 416 of the 1245 potential study patients were reviewed to identify the final incident cohort of 150 patients for in-depth review. The list of 1245 people was placed in random order using a pseudorandom number generator, and medical records were reviewed until the final sample of 150 people who met inclusion criteria was identified. The 150th patient s data could not be used after the patient revoked general research authorization during the data analysis phase. Potential patients from the group of 416 were excluded primarily for 1 of 3 reasons: prevalent rather than incident IBS (n = 67), no diagnosis of IBS documented in the medical chart (n = 41), and a resident of Olmsted County for <3 years (n = 93). Another 66 people had miscellaneous reasons for exclusion, including a diagnosis date outside the window of study, age <16 years at diagnosis, and missing medical records. The 3-year residency rule was based on the observation that after diagnosis of IBS, physician visits were uncommon, making it difficult to distinguish prevalent and incident cases with only a 1-year window. All medical records of patients meeting the eligibility criteria were reviewed to abstract data on demographic characteristics, visits for GI tract or abdominal problems, and visits for non-gi tract symptoms from 10 years before the first IBS diagnosis to 3 years after. Gastrointestinal tract symptom related visits were those in which any symptom, sign, or complaint referable to the GI tract was recorded, including diarrhea, abdominal pain, constipation, change in stool habits, and vomiting. All other visits were considered non- GI tract related. Information on the presenting complaint, 586 THE AMERICAN JOURNAL OF MANAGED CARE JUNE 2001

3 ... Diagnosis and Care of IBS... specialty of physician seen, tests and treatment ordered, and site of the visit were recorded. Data collection began at the earliest visit that occurred 10 years before the incident IBS diagnosis. Data Analysis Descriptive information is presented as summary statistics and labeled line plots. 17 Healthcare utilization was stratified into 3 major periods: (1) the 60 days surrounding the incident IBS diagnosis (30 days before to 30 days after); (2) the 10 years before the diagnosis, excluding the 30 days immediately before; and (3) the 3 years after the diagnosis, excluding the 30 days immediately after. The designation of the 60-day diagnostic period was based on the clinical judgment of the authors and was believed to reflect the usual time required to complete a diagnostic evaluation. The mean number of services per person was annualized, except for those in the 60-day diagnostic period. Comparisons between periods were made using the Wilcoxon signed rank test. Comparisons between age groups and sexes, within a period, were made using the Wilcoxon rank sum test. Chi-square tests were used to compare frequencies of events. This study was approved by the institutional review boards of the Olmsted Medical Center and the Mayo Medical Center.... RESULTS... The 149 patients (66% women) had a mean (standard deviation) age at diagnosis of IBS of 46.6 (17.8) years (range, years), with no significant age by sex interactions. Eighty-three percent of patients had data available for the full 10 years before and the 3 years after the index IBS diagnosis. None of the patients had participated in IBS-related clinical trials or survey studies. Both men and women were frequent and consistent users of healthcare services (P =.16 for difference in use by sex), with no trend for increasing or decreasing visits by age groups (P =.20 for trend). In the 10 years before the incident diagnosis of IBS, patients made an average of 4.7 physician visits per person per year, with more than 85% making visits in any year. Visits included an annual average of 4.1 visits not related to GI tract symptoms, 0.5 related to GI tract symptoms, and 0.1 for psychiatric care. There was no marked change in the visit pattern immediately preceding IBS diagnosis, and visits did not decline precipitously following diagnosis (Table 1) (P =.13 for changes in the annual visit rate for 2 years before and 3 years after diagnosis). Visits related to GI tract symptoms (Table 2) never accounted for >25% of all annual visits. The percentage of men and women making any annual visit related to GI tract symptoms increased toward the time of IBS diagnosis (Table 2). The Figure illustrates the pattern of scattered clusters of visits related to GI tract symptoms in men and women aged 40 to 50 years. Visits for GI tract complaints occurred during a prolonged period, with 46% of patients having 1 visits for GI tract complaints by 4 years before the incident IBS diagnosis and 64% by 2 years before. At the time of diagnosis, visits for GI tract symptoms were universal, but they decreased again soon after the diagnosis. Although prediagnostic GI tract symptom related visit frequency varied little by age and sex, people in the youngest age group (16-34 years) were more likely to continue having visits for GI tract symptoms after IBS diagnosis than those aged 35 to 54 years and 55 years (50% vs 29% and 33%, respectively; P =.03). Table 2. Annualized Visits Related to Gastrointestinal Tract Symptoms Visits, mean No. (%)* Age y Age y Age 55 y Women Men Period (n=46) (n=51) (n=52) (n=99) (n=50) +2 y to +3 y 0.9 (29) 0.4 (30) 0.6 (40) 0.6 (36) 0.7 (28) +1 y to +2 y 0.5 (21) 0.7 (29) 0.6 (35) 0.6 (30) 0.6 (26) +30 d to +1 y 0.9 (52) 0.5 (26) 0.7 (39) 0.6 (39) 0.8 (37) -30 d to -1 y 0.9 (33) 0.7 (35) 0.9 (37) 0.8 (35) 0.9 (34) -1 y to -2 y 0.5 (35) 0.3 (18) 0.3 (17) 0.4 (26) 0.2 (16) -2 y to -5 y 0.5 (22) 0.3 (17) 0.3 (21) 0.4 (0.2) 0.3 (19) -5 y to -10 y 0.3 (14) 0.2 (13) 0.1 (11) 0.2 (14) 0.2 (10) *Percentage of patients who had any visits during the period. VOL. 7, NO. 6 THE AMERICAN JOURNAL OF MANAGED CARE 587

4 ... HEALTHCARE UTILIZATION... Neither men (14%) nor women (20%) were likely to visit a gastroenterologist at any time during the 13 years of observation, and no significant age or sex patterns were discernible. During the IBS diagnostic period (60 days surrounding the diagnosis), 12% of women and 2% of men visited a gastroenterologist. Of the 149 diagnoses of IBS, only 8 (5%) were made by gastroenterologists. Abdominal pain was the most common reason for visits leading to an IBS diagnosis, with 75% of all patients with IBS having 1 visits for abdominal pain in the 2 years before IBS diagnosis. Although bowel dysfunction was less commonly listed as the reason for a visit, 90% of all patients with IBS had 1 visit in which either constipation or diarrhea was recorded in the 2 years before diagnosis of IBS. Diarrhea was recorded almost twice as often as was constipation (56% vs 29%). Over time, complaints seemed to cluster into 2 large groups: abdominal pain, and diarrhea with or without periodic complaints of pain. Constipation was documented in many patients with episodes of diarrhea but in only a few presenting primarily with abdominal pain. Gastrointestinal Tract Test Utilization Gastrointestinal tract tests (including blood tests) were common during the diagnostic period, and the frequency increased with patient age (16-34 years, 61%; years, 75%; and 55 years, 81%). The percentages are higher if the 2 years before the diagnosis are included (76%, 84%, and 96%, respectively). The most common tests performed during the diagnostic period were blood tests, primarily assessment of hemoglobin levels or serum chemistry multitest panels (49%). Imaging and endoscopic studies were also common in the time surrounding the first IBS diagnosis, with more than 47% of patients undergoing at least 1 such study. Colon tests included contrast radiography of the colon (barium enema) (37%), rigid or flexible sigmoidoscopy (18%), Figure. Healthcare Utilization Pattern of Patients Aged 40 to 50 Years at the Time of Incident Irritable Bowel Syndrome Diagnosis -8 Years Before or After Diagnosis Day at Diagnosis, y = Women = Men = Primary care visit = Specialist care visit Each vertical line represents a single patient. Each diamond indicates a visit for gastrointestinal tract complaints. 588 THE AMERICAN JOURNAL OF MANAGED CARE JUNE 2001

5 ... Diagnosis and Care of IBS... abdominal ultrasound (12%), abdominal computed tomographic scans (4%), and colonoscopy (3%). Stool tests for blood (11%) and for infectious agents (19%) were not uncommon. With the period of testing expanded to include the 2 years before the first IBS diagnosis, 44% of patients had a barium enema, a colonoscopy, or both. As demonstrated in Table 3, the patterns of testing did not vary by sex. However, colon examinations were more common in patients 55 years and older compared with those younger than 55 years (58% vs 36%; P =.02). Of those not undergoing a barium enema or colonoscopy in the 2 years before IBS diagnosis, 13% had a sigmoidoscopy and 11% had stool blood testing. One third of patients (32%) had no colon examination or stool occult blood test documented before the first IBS diagnosis. During the 3 years of follow-up, 1 patient (aged 23 years) had a diagnostic change from IBS to inflammatory bowel disease. No cases of colon cancer were diagnosed during follow-up. Medication Use Related to IBS Eighty-three percent of patients diagnosed as having IBS (76% of men and 87% of women) had documentation of treatment with some type of GI tract-related medication. Documentation of GI tract medication use actually increased significantly in the year before the incident diagnosis of IBS (P =.04) and then remained constant for the first year after IBS diagnosis. Documentation of IBS medication use declined again shortly after the initial IBS diagnosis, returning to its earlier levels (Table 4). Fiber was the most commonly recommended IBSrelated medication documented in the medical records (48% of patients). Antacids were suggested in 18% of patients, antidiarrheal prescriptions in 8%, and laxatives in 5%. Abdominal pain was documented in 75% of all patients in the 2 years before IBS diagnosis. However, use of specific pain medications and antispasmodic medications was uncommon (3% of patients). Histamine blockers were used primarily in the year before the diagnosis and predominantly by men. Use decreased after IBS was diagnosed. By 1 year after diagnosis, only 26% of patients with IBS had continued use of any IBS-related medications documented in the medical record. Use of psychotropic medications was uncommon in the year before (mean, 0.19 prescriptions per person and use by 10% of patients) and about the same in the year after (mean, 0.13 prescriptions per person and use by 7% of patients) diagnosis. There were few age- and sex-associated differences in documented IBS-related drug prescriptions. Women were slightly more likely to use medications for bowel dysfunction (laxatives and antidiarrheals) than men (P =.05), and men were more likely to have prescriptions for histamine blockers (P =.01) and antidepressant and antianxiety medications (P =.03) (data not shown). Irritable bowel syndrome-related counseling and patient education did not seem to be common activities or at least were seldom documented, appearing in <8% of patient medical charts in any single year and occurring in only 18% of patients cumulatively during the 3 years following diagnosis of IBS.... DISCUSSION... The path to diagnosis of IBS was based in the generalist s office, included occasional visits for GI tract Table 3. Patients Undergoing Specific Gastrointestinal Tract Tests by Period and Sex Colonoscopy Sigmoidoscopy Barium Enema Stool Blood Period Men, % Women, % Men, % Women, % Men, % Women, % Men, % Women, % +2 y to +3 y y to +2 y d to +1 y d to +30 d d to -1 y y to -2 y VOL. 7, NO. 6 THE AMERICAN JOURNAL OF MANAGED CARE 589

6 ... HEALTHCARE UTILIZATION... symptoms during several years, and used minimal testing. Men and women had similar paths, but neither fit the stereotype of patients with a prolonged pattern of frequent physician visits for chronic GI tract complaints. Gastrointestinal tract testing before IBS diagnosis was not universal but seemed to be tailored to patient age, type and chronicity of symptoms, and previous probabilities of other GI tract conditions, especially colon cancer. The rapid decline in documented IBS treatment following diagnosis of IBS may reflect the lack of IBS-specific therapy before 2000, frustration with prescribed therapy, or use of over-the-counter medication requiring no physician contact. Individuals with IBS are reported to be high users of healthcare, 13 and our cohort has documented office visits at more than 2.5 times the national average (4.7 vs 1.4 annual visits per person) based on estimates from the 1996 National Ambulatory Medical Care Survey. 18 Although seen only periodically for GI tract symptoms, visits for GI tract complaints were 10 times more common in patients with IBS than in the general population. 18 In the general population, healthcare utilization varies by age and sex, with women and older patients having a higher annual rate of visits. 6,19 In this IBS cohort, utilization was high but varied little by age or sex, and most visits were not directly related to GI tract complaints. We cannot rule out the possibility that this cohort represents a group with high healthcare-seeking behavior and that the greater exposure to the healthcare system provided more opportunity to diagnose IBS. Whereas overall healthcare utilization in our cohort seems high, IBS-related visits were less common (mean, 0.53 visits per year after IBS diagnosis) than reported for patients with IBS receiving care from 60 general practitioners in the United Kingdom (mean, 1.6 visits per year). 20 The 3-fold difference in visit rates could represent differences in access to physicians, differences in practice patterns, or differences in how patients with IBS are treated and followed up in the 2 countries. In this population, as in the United Kingdom populations, IBS is a condition principally diagnosed and treated by primary care physicians. 12,13 Despite the reported high percentage of gastroenterologists patients who have IBS, 8,13,21,22 referral to a gastroenterologist was uncommon before, at the time of, and after diagnosis of IBS. Because of the frequency of the disease in the population and the low rate of referral, descriptions of IBS and the care of people with IBS based on gastroenterology clinic populations might be misleading. The annual rate of psychiatric visits in the US population (0.10 per individual per year) 18 was similar to the rate seen in this IBS cohort. Other studies 4,23,24 report conflicting results regarding the demand for psychological services among patients with IBS. Referral populations in particular have been reported to have higher rates of psychological Table 4. Patients Taking Specific Categories of Drugs by Period and Sex Any Antidepressant/ IBS- Antidiarrheal Antispasmodic Histamine Antianxiety Related Drug Laxatives Drugs Drugs Fiber Blockers Drugs Men, Women, Men, Women, Men, Women, Men, Women, Men, Women, Men, Women, Men, Women, Period % % % % % % % % % % % % % % +2 y to +3 y y to +2 y d to +1 y d to +30 d d to -1 y y to -2 y y to -5 y y to -10 y THE AMERICAN JOURNAL OF MANAGED CARE JUNE 2001

7 ... Diagnosis and Care of IBS... distress compared with community populations. 24 In this group, the path to diagnosis of IBS seldom included psychiatric care or evaluation, and our results suggest that these community-based patients with IBS did not have increased levels of psychiatric problems. Almost one third of these patients, including several older than 50 years, did not undergo colon tests in the 2 years before IBS diagnosis. Many organizations have recommended regular colon cancer screening for asymptomatic people older than 50 years. 25,26 It would seem that not performing at least stool testing for occult blood in this symptomatic population, especially those older than 50 years, is a missed screening opportunity. For younger age groups, the lack of testing completed along the path to IBS diagnosis seems less surprising. Diagnosis of IBS is often based on a pattern of visits for similar symptoms for months or years, making the prior probability of other significant GI tract pathological findings low. This path of watchful waiting leading to IBS diagnosis has been described in the British generalist literature 27 and is markedly different than the path of extensive testing recommended in the US specialty literature. 28 The community physicians in this study seem to be discriminating in their evaluations, with an appropriate if not adequate increase in testing in the older age group. However, the diagnostic testing in our population seems to be more common than the rate recently reported in a managed care population. 29 Comparisons across studies are difficult. The managed care study is based on diagnoses from an administrative database, without confirmation of IBS diagnosis, knowledge of the date of the incident diagnosis, or the documented reasons for the GI tract tests. This study is limited by the data available in medical records. Although medical records may be a good source of complete healthcare utilization data, they are not perfect. It is uncommon for visits or tests not to be recorded, but telephone care is seldom recorded, and prescriptions, especially refills, as well as many over-the-counter drugs may not be documented in the medical record. This study does not provide data on the entire population of community patients with IBS, only those seeking care from physicians. This is, however, the first study to document healthcare utilization over such an extended period in a population-based incidence cohort centered on the time of diagnosis. The use of IBS-specific drugs is not reflected in these data, which were collected before introduction of any IBS-specific drugs to the US market. It is possible that the new drug will modify utilization data and the path to diagnosis of IBS by changing the use of diagnostic procedures, follow-up care, and drug prescribing patterns among US physicians. It will be interesting to assess this change in future studies of this population.... CONCLUSION... The path to diagnosis of IBS is through outpatient primary care during months or years of care, with few diagnoses originating in specialty care clinics. Diagnostic testing is minimal and seems to be tailored to the patient s age, symptoms, and prior probability of more serious GI tract conditions.... REFERENCES Lynn RB, Friedman LS. Irritable bowel syndrome. N Engl J Med 1993;329: Manning AP, Thomson WG, Heaton KW, Morris AF. Toward positive diagnosis of the irritable bowel. BMJ 1978;2: Tally NJ, Phillips SF, Melton LJ III, Mulvihill C, Wiltgen C, Zinsmeister AR. Diagnostic value of the Manning criteria in irritable bowel syndrome. Gut 1990;31: Maxwell PR, Mendall MA, Kumar D. 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