['We examined whether patients with a diagnosis of fibromyalgia have an increased risk of coronary heart disease (CHD), compared with age- and sex-matched control patients. We hypothesized that patients diagnosed with fibromyalgia are at increased risk of adverse coronary events.', 'Using a matched-cohort study design, we analyzed data retrieved from the Longitudinal Health Insurance Database 2000 released by the National Health Research Institute, Taiwan. The Longitudinal Health Insurance Database 2000 includes medical claims data and registration files for 1 million enrollees randomly selected from the 2000 Registry for Beneficiaries (n = 23.72 million) of the National Health Insurance program. Patients treated for fibromyalgia at least once a month for 3 consecutive months following their initial diagnosis were enrolled in our study. The primary end point was the composite of CHD events, including percutaneous coronary interventions and coronary artery bypass grafting procedures. A propensity score was estimated by a logistic regression method, in which the fibromyalgia status was regressed on baseline prognostic factors. The hazard ratios and the 95% confidence intervals were estimated using multivariate Cox proportional-hazards regression models while adjusting for the propensity score.', 'After adjusting for the propensity score, the patients with fibromyalgia showed a significantly higher subsequent risk of a CHD event (hazard ratio, 2.11; 95% confidence interval, 1.46-3.05; P < 0.001) than the patients without fibromyalgia.'] Is fibromyalgia associated with coronary heart disease : a population-based cohort study?