To quantify and compare direct costs, utilization, and the rate of comorbidities in a sample of patients with fibromyalgia (FM), a poorly understood illness associated with chronic widespread pain that is commonly treated by rheumatologists, to patients with rheumatoid arthritis (RA), a well studied rheumatologic illness associated with inflammatory joint pain. Patients with both illnesses were isolated and reported as a third group. A secondary analysis of work loss was performed for an employed subset of these patients.
Retrospective cohort analysis of Thomson Reuters MarketScan administrative healthcare claims and employer-collected absence and disability data for adult patients with a diagnosis of FM (ICD-9-CM 729.1) and/or RA (ICD-9-CM 714.0x,-714.3x) on at least one inpatient or two outpatient claims during 2001-2004.
The 12-month healthcare utilization, expenditures, and rates of comorbidities were quantified for all study-eligible patients; absence and short-term disability days and costs were quantified for an employed subset.
The sample included 14034 FM, 7965 RA, and 331 FM+RA patients. Patients with FM had a higher prevalence of several comorbidities and greater emergency department (ED) utilization than those with RA. Mean annual expenditures for FM patients were $10911 (SD=$16075). RA patient annual expenditures were similar to FM: $10716 (SD= $16860). Annual expenditures were almost double in patients with FM+RA ($19395, SD= $25440). A greater proportion of patients with FM had any short-term disability days than those with RA (20 vs. 15%); and a greater proportion of patients with RA had any absence days (65 vs. 80%). Mean costs for absence from work and short-term disability in the FM and RA groups were substantial and similar. The FM+RA group was of insufficient sample size to report on work loss.
The availability of newer and more expensive FDA-approved medications since 2004 is not reflected in our findings. This analysis was restricted to commercially insured patients and therefore may not be generalizable to the entire U.S. population.
The burden of illness in FM is substantial and comparable to RA. Patients with FM incurred direct costs approximately equal to RA patients. Patients with FM had more ED, physician, and physical therapy visits than RA patients. Patients in both groups had several comorbidities. Patients with FM+RA incurred direct costs almost double those of the patients with either diagnosis alone. FM and RA patients incurred similar overall absence and short-term disability costs.