Case-control study of medical comorbidities in women with interstitial cystitis

Purpose: We used physician assigned diagnoses in an electronic medical record to assess comorbidities associated with interstitial cystitis. Materials and Methods: A computer search of the administrative database at Kaiser Permanente Northwest, Portland, Oregon was performed for May 1, 1998 to April 30, 2003. All women with a medical record diagnosis of interstitial cystitis JCD-9 code 595.1) were identified. These cases were then matched with 3 controls each based on age and duration in the health plan. The medical diagnoses (using ICD-9 codes restricted to 3 digits) assigned to these 2 groups were compared using the OR. Results: A total of 239 cases and 717 matched controls were analyzed. There were 23 diagnoses that were significantly more common in cases than in controls (p <= 0.005). Seven of these 23 diagnoses were other urological or gynecological codes used to describe pelvic symptoms. Additional specific conditions associated with interstitial cystitis were gastritis (OR 12.2), child abuse (OR 9.3), fibromyalgia (OR 3.0), anxiety disorder (OR 2.8), headache (OR 2.5), esophageal reflux (OR 2.2), unspecified back disorder (OR 2.2) and depression (OR 2.0). Conclusions: A diagnosis of interstitial cystitis was associated with multiple other unexplained physical symptoms and certain psychiatric conditions. Studies to explore the possible biological explanations for these associations are needed. Interstitial cystitis was also associated with a history of child abuse, although 96% of patients with IC did not have this diagnosis.