Multiple Drug Intolerance Syndrome in Fibromyalgia

Abstract

Multiple drug intolerance syndrome (MDIS) describes patients with non-immunologic reactions to ≥3 drug classes. This can severely limit treatment options for affected patients. Rates of MDIS in fibromyalgia have not been previously described 1,479 patients with a diagnosis of fibromyalgia seen within our university health system in the last year were evaluated by retrospective chart review. Based on prior studies, patients with 10 or more listed allergies were considered to have MDIS. Chi-square testing and binary logistic regression were used for analysis. 128 (8.65%) patients with fibromyalgia met the definition of MDIS. The average number allergies listed for fibromyalgia patients was 3.7, while the average for age and sex matched controls was 1.4. On regression analysis, patients with fibromyalgia were found to be 6 times more likely to have MDIS (OR 6.29, CI 4.74-8.36). An active diagnosis of anxiety (X2 = 13.00, p < 0.0001) or depression (X2 = 7.14, p =0.008) was associated with MDIS. A Charlson Comorbidity Index score of ≥4 was associated with MDIS in patients with fibromyalgia (X2 = 41.44, p < 0.0001) and estimates a 10 year survival of 53%. Additionally, having >10 outpatient visits within the last year was associated with MDIS (X2 = 30.79, p < 0.0001 The association of MDIS with multiple comorbidities and frequent health care utilization in patients with fibromyalgia raises concerns that MDIS may limit therapies in these already complex patients. Additional studies are needed to explore this further.