Medication persistence over 2 years of follow-up in a cohort of early rheumatoid arthritis patients: Associated factors and relationship with disease activity and with disability

Abstract

Introduction: Aggressive treatment with disease-modifying antirheumatic drugs (DMARDs) plays a major role in improving early rheumatoid arthritis (RA) patient outcomes. Persistence and adherence with medication occurs variably (20% to 70%). The objectives of the study were to determine medication persistence (MP) in early RA patients over 13 consecutive visits each 2 months apart, to investigate the relationship between MP and disease activity, disability and structural damage, and to identify baseline prognosticators. Methods: Charts from 75 patients of an early RA cohort were reviewed. At each visit, a rheumatologist interviewed patients regarding therapy, scored disease activity with the 28-joint disease activity score (DAS28) and disability with the health assessment questionnaire (HAQ), and recorded comorbidities and treatment. A complete medical history was obtained at baseline. MP was defined as the duration of time from initiation to discontinuation of at least one DMARD and/or corticosteroids for at least 1 week and was reported as a dichotomous variable at consecutive evaluations. Structural damage was defined by detection of new erosions on radiography. Descriptive statistics, Student's t test, the chi-squared test, and logistic regression analyses were used. Results: The proportion of MP patients decreased from 98% at 2 months to 34% at 2 years. MP patients (n = 32) had similar DAS28 to non-MP patients (n = 53) at initial visits, lower DAS28 and greater DAS28 improvements at follow-ups (P ≤ 0.05 at visits 4, 6, 7 and 9) and reached sustained remission (≥ 3 consecutive visits with DAS28 < 2.6) more frequently (82.8% versus 46.5%, P = 0.003) and earlier (7.7 ± 4.6 versus 13.6 ± 5.7 months, P = 0.001) than non-MP patients. MP patients had similar baseline HAQ scores, but lower HAQ scores at follow-up (P ≤ 0.05 at visits 3, 5, 6, 7, 9, 10 and 13). More non-MP patients developed erosive disease than MP patients (26.8% versus 17.9%, P = 0.56). Older age at baseline was associated with therapy discontinuation (odds ratio = 1.1, 95% confidence interval = 1.007 to 1.103, P = 0.02). Conclusions: Discontinuation of DMARDs was frequent and progressive in an early RA cohort. Patients with persistence on therapy were younger, had lower disease activity and disability during follow-up, and reached sustained remission more frequently and earlier than patients without it. MP should intentionally be evaluated during follow-up of early RA patients, as it seems to play a major role in outcome. © 2009 Pascual-Ramos et al.; licensee BioMed Central Ltd.