Costs of care for irritable bowel syndrome patients in a health maintenance organization

OBJECTIVES: The aims of this study were: 1) to determine the total costs of care and costs related to lower GI-related problems for patients who received a diagnosis of irritable bowel syndrome (IBS), and 2) to compare them to age- and sex-matched population controls and patients treated for inflammatory bowel disease (IBD) or gastroesophageal reflux disease (GERD). METHODS: Use and cost data were obtained through the computerized information systems of a large staff-model health maintenance organization on three groups of patients diagnosed in 1994 or 1995 with IBS, IBD, or GERD; and an age- and sex-matched control group of patients without any of these listed diagnoses. The IBS patient group was compared to the three comparison groups on components of total and IBS-related costs. RESULTS: Total costs of care for IBS patients were 49% higher than population controls during the year starting with the visit at which IBS patients were identified. In the index year, every component of total costs except inpatient care was significantly higher for IBS patients than for population controls. The costs of care for lower GI problems were significantly higher for patients with IBS than for population controls across a range of services. However, only 33% of the difference in total costs of care between IBS patients and population controls was due to lower GI-related services in the index year. In the subsequent years, lower GI-related services accounted for 18% and 20% of the total cost difference between IBS patients and population controls. The total costs of care as well as the components of costs of care were generally higher for IBD patients than for IBS patients, but were comparable for GERD and IBS patients. CONCLUSIONS: Patients with IBS show sustained increases in health care costs relative to population controls for both lower GI services and care unrelated to lower GI problems. However, the majority of the excess in health care costs resulted from medical care not directly related to lower GI problems.