OBJECTIVES: Investigate the association between Disease Activity Score 28 C-Reactive Protein (DAS28-CRP) score, disease duration and patient costs in rheumatoid arthritis (RA) patients, using data from the Burden of Rheumatoid Arthritis across Europe: a Socioeconomic Survey (BRASS).

METHODS: Data were extracted from BRASS, a societal perspective observational RA dataset across 10 European countries (EU5, Denmark, Sweden, Hungary, Poland and Romania). 476 RA specialising clinicians provided information on 4,079 adult patients; of these, 2,087 patients completed corresponding questionnaires about the burden of RA. Twelve-month costs captured included: consultations, testing, hospital admissions and procedures, payments to professional caregivers, travel costs, requirement for aids/equipment and informal care costs. Indirect costs captured from the patient included work productivity impact.

A generalised linear model was developed to investigate the association between disease duration, most recent DAS28-CRP score and total cost of patients excluding costs of conventional synthetic and biologic disease modifying drugs. Disease duration and DAS28-CRP score were modelled as explanatory variables against the total cost response variable, adjusted for covariates including age, gender and BMI.

RESULTS: The model provided adequate fit, uncertainty from between-country unit cost differences was investigated, and association between the variables of interest remained. The average marginal effect at the mean was calculated from regression outputs. Both disease duration and DAS28-CRP score had a statistically significant association with total cost; a unit increase in DAS28 score meant a total cost increase of €1,075 (p=0.004), whereas a unit increase in disease duration of one year increased total cost by €360 (p=0.012), with confounders age, gender, BMI and either DAS28-CRP or duration held at mean values. Descriptive analysis indicated that with greater duration of disease and/or disease activity, healthcare costs incurred outweigh treatment costs.

CONCLUSIONS: Analysis suggests that disease duration and disease activity have a significant impact on total patient cost.