Healthcare costs associated with chronic opioid use and fibromayalgia syndrome

Background: Fibromyalgia (FM) is an idiopathic, functional syndrome characterized by chronic, widespread pain and diffuse tenderness. This disorder affects more than 6 million patients in the United States and is associated with significant clinical and economic burdens. Objectives: The objectives of this study were to: 1) estimate the costs associated with a FM diagnosis; and 2) estimate the impact of chronic opioid use on the costs of FM patients. Research Design: Case-control study. Methods: Subjects were identified in a large nationally representative database of commercially insured patients. Propensity score-matched analyses included 445,912 FM-control pairs in the first analysis, while the second analysis included 48,333 chronic opioid users with the FM-control pairs. Primary outcomes of interest were the medical and prescription costs compared between matched pairs, based on propensity for being a case as evidenced by coefficients obtained from a first-stage logistic regression. Patient characteristics considered include: state of residence, diagnosing provider type, comorbid conditions, and concurrent medication use. Results: When controlling for propensity to receive a FM diagnosis, the actual diagnosis has a small effect on medical (–$83.54 [95% CI, –152.55 to –16.53]) and prescription ($120.31 [95% CI, 109.98-130.62]) costs. However, the effect of chronic opioid use in FM patients on medical ($9094.05 [95% CI, 8924.79- 9263.31]) and prescription ($3391.81 [95% CI, 3368.84- 3414.79]) costs is much more substantial. Conclusions: While the differences seen in FM patients and controls are marginal, those attributed to chronic opioid use in these patients are significantly higher. Chronic opioid therapy to treat FM is a practice based not on evidence available to practitioners, but on other variables.