Increased risk of a suicide event in patients with primary fibromyalgia and in fibromyalgia patients with concomitant comorbidities A nationwide population-based cohort study

An increased risk of suicide ideation and death has been reported in patients with fibromyalgia. This study aimed to evaluate the risk of a suicide event in patients with primary fibromyalgia and in fibromyalgia patients with comorbidities. We used the Longitudinal Health Insurance Database, a subset of the national insurance claim dataset, which enrolled 1 million Taiwanese people from 2000 to 2005, to identify 95,150 patients with incident fibromyalgia (ICD-9-CM 729.0-729.1) and 190,299 reference subjects matched by sex, age, and index date of diagnosis, with a mean of 8.46 +/- 2.37 years of follow-up until 2011. The risk of a suicide event (ICD-9-CM, External-Cause Codes 950-959) was analyzed with a Cox proportional hazards model. Stratification analysis was performed by separating fibromyalgia patients and reference subjects with respect to each comorbidity to determine the risk of suicide in fibromyalgia patients with or without comorbidity relative to subjects who had neither fibromyalgia nor comorbidity. In this Taiwanese dataset, there were 347 suicide events in patients with fibromyalgia (4.16 per 10(4) person-years) and 424 in matched reference subjects (2.63 per 10(4) person-years) with a significant crude hazard ratio (HR) of 1.58 (95% confidence interval [CI] 1.38-1.83) and an adjusted HR of 1.38 (95% CI 1.17-1.71) for fibromyalgia patients relative to the matched reference subjects. According to the 2 x 2 stratification analysis, we found that fibromyalgia patients without comorbidity had an independent but mild risk of a suicide event with adjusted HRs ranging from 1.33 to 1.69 relative to subjects with neither fibromyalgia nor comorbidity. Meanwhile, fibromyalgia patients with comorbidity led to a markedly enhanced risk of a suicide event relative to the matched reference subjects, with adjusted HRs ranging from 1.51 to 8.23. Our analysis confirmed a mild-to-moderate risk of a suicide event in patients with primary fibromyalgia. Attention should be paid to the prevention of suicide in fibromyalgia patients with concomitant comorbidities.