Direct medical costs of polymyalgia rheumatica

Abstract

To describe the patterns of care and direct medical costs of polymyalgia rheumatica (PMR) to test the hypothesis that the direct medical costs incurred by patients with PMR are higher than costs incurred by age- and sex-matched population-based controls from the same community. The study population comprised 193 Olmsted County, Minnesota residents who were first diagnosed with PMR between January 1, 1987 and December 31, 1999. Inclusion criteria were as follows: age > or = 50 years; bilateral aching and morning stiffness (lasting > or = 30 minutes) persisting for at least 1 month and involving the neck, shoulders, or hip girdle regions; and an erythrocyte sedimentation rate (ESR) > or = 40 mm/hour. In patients who fulfilled the first 2 criteria, but had a normal ESR, a rapid response to low-dose corticosteroids served as the third criterion. A total of 695 age- and sex-matched subjects without PMR served as control subjects. Billing data from the Olmsted County Healthcare Expenditure and Utilization Database (OCHEUD) were used to provide estimates of nationally representative unit costs in the year 2002 inflation-adjusted dollars. All subjects were followed using the OCHEUD records until December 31, 2002 to assess the total direct medical costs. Generalized quantile regression modeling was used to estimate the effect of PMR on direct medical costs, after adjusting for age, sex, Charlson comorbidity score, number of hospital days, and number of radiographs. During the first year following diagnosis, subjects with PMR used a substantially higher number of outpatient services and laboratory tests compared with controls, but during the subsequent 4 years, there were no differences between the 2 groups. In age- and sex-adjusted analysis, PMR was associated with a significant incremental cost of 2,233 dollars at the 10th percentile of costs and 27,712 dollars at the 90th percentile of costs. However, further adjustments for comorbidities, number of hospital days, radiographs, and imaging eliminated the incremental cost difference between the subjects with PMR and control subjects. PMR subjects were significantly more likely to have a history of myocardial infarction (odds ratio [OR] 1.78, 95% confidence interval [95% CI] 1.13, 2.82), peripheral vascular diseases (OR 2.21, 95% CI 1.37, 3.60), and cerebrovascular diseases (OR 1.60, 95% CI 1.08, 2.39) compared with the controls. Incremental direct medical costs associated with the management of PMR can be substantial, especially early in the disease course. These incremental costs appear to originate mainly from comorbid cardiovascular conditions that were shown to be more prevalent among subjects with PMR.