A portrait of fibromyalgia using Nationwide Inpatient Sample data

BACKGROUND: Fibromyalgia is a controversial chronic pain condition affecting approximately 2-4% of all adults, but mostly women. Fibromyalgia patients account for more medical cost, medication use, physician visits, and disability when compared to other chronic pain patients. Prevalence, co-morbidity, and cost estimates, however, largely are based on regional and small clinical samples or claims data within a particular health care system. Limited information exists about hospitalization. OBJECTIVE: To conduct an epidemiological study including multiple insurance types, examining men and women with fibromyalgia-related hospitalizations in the United States. METHOD: All discharges between 1999 and 2007 with an ICD-9 diagnosis of 729.1 were selected from Nationwide Inpatient Sample data. Sampling procedures using Stata/SE 11.0 were used to generate the estimated number of annual discharges by gender. Population estimates were obtained from the Census Bureau. RESULTS: Between 1999 and 2007, there were an estimated 1.7 million hospital discharges with a fibromyalgia diagnosis. Men comprised 12.3% of these discharges. Estimated annual rates were 52 discharges per 100,000 population for men and 229 for women. The most common principal major diagnostic categories were musculoskeletal system and connective tissue (20.7% among men, 17.0% among women), circulatory system (19.4 and 16.4%), digestive system (8.2 and 12.6%), respiratory system (10.4 and 10.7%), and mental diseases and disorders (6.3 and 8.4%). Mean charges were $19,366 for men and $18,290 for women. DISCUSSION: This novel, national ‘portrait' of fibromyalgia-related hospital discharges, co-morbidities, and costs may be useful for better understanding fibromyalgia and addressing its medical complexities and costs.