Determinants of direct costs in Dutch rheumatoid arthritis patients

Objectives: To estimate annual direct costs in four distinct disease duration groups (0 to ≤ 2, 2 to ≤ 6, 6 to ≤ 10, and > 10 years) of patients with rheumatoid arthritis (RA), to determine predictors of high costs and to describe characteristics of patients with high and with low costs. Methods: A questionnaire assessing RA related care and resource utilisation rates and costs was completed by 615 RA patients. Predictive variables for incurred costs, as observed during the first year after disease onset, were determined in a subgroup of patients (n = 347). Results: Mean (median) annual direct costs for the four groups with increasing disease duration were respectively: €5235 (2923), €3930 (1968), €4664 (1952), and €8243 (3778), (p <0.05). During the first 2 years of the disease total direct costs comprised mainly of consultations with heatlhcare workers (28%). After 10 years, devices and adaptations were the main contributors (40%) to total costs. Positive rheumatoid factor results at the time of diagnosis and deterioration of functional disability in the first year of disease were predictors of high costs later on in the course of the disease. Conclusion: Annual direct costs among patients with a disease duration of less than 2 years tend to be lower among patients with a disease duration of between 2 and 10 years than among patients with a disease duration of more than 10 years. In addition, the proportional distribution of different cost categories to total costs increases with with increasing disease duration.