Medical conditions in fibromyalgia patients and their relationship to pregabalin efficacy: pooled analysis of Phase III clinical trials.

Objective: Patients with fibromyalgia demonstrate high rates of comorbid somatic and psychiatric disorders. The current post hoc study analyzed the prevalence of comorbid conditions and their relationship to pregabalin efficacy in patients with fibromyalgia pooled from four Phase III clinical trials. Methods: Patients diagnosed with fibromyalgia according to the American College of Rheumatology criteria, randomized to placebo or 300, 450, or 600 mg/day pregabalin, and with 1 postbaseline pain score were included. The frequency of comorbid conditions was obtained from patient-reported, voluntary medical histories. Patients were categorized based on the presence of a medical condition (e. g., irritable bowel syndrome) or a group of medical conditions (e. g., neurological disorders). Two efficacy variables were examined within each comorbid category: endpoint changes from baseline in weekly mean pain diary scores (11-point numeric rating scale) and Patient Global Impression of Change. Results: A large proportion of patients exhibited concomitant headache, immunological (allergy), gastroesophageal, and/or psychiatric disorders. The efficacy analyses performed on these subgroups of patients, amongst others, showed - with few exceptions - consistent pain reductions of similar magnitude with pregabalin. Conclusion: Comorbid conditions are common among patients with fibromyalgia and their presence is not associated with altered pregabalin efficacy.