Do rheumatologists know best? An outcomes study of inconsistent users of disease-modifying anti-rheumatic drugs

Current recommendations advocate treatment with disease-modifying anti-rheumatic drugs (DMARDs) in all patients with active rheumatoid arthritis (RA). We analyzed short-term disease outcome in patients according to the consistency of DMARD use in a clinical rheumatology cohort.

Patients in an RA registry (n = 617) were studied for DMARD use at semi-annual study time points during the first 18 months of follow-up and were divided into 4 groups according to the number of study time points with any DMARD use [0-1 study time points (n = 31), 2 study time points (n = 24), 3 study time points (n = 77), and 4 study time points (n = 485)]. The primary outcome analyses were performed at 24 months and included Disease Activity Score 28 (DAS28-CRP), modified Health Assessment Questionnaire (MHAQ) change, Short Form Health Survey-12 physical and mental summary scores (SF-12 PCS, SF-12 MCS), EuroQol 5-Dimensional health index (EQ-5D), and radiographic progression. Unadjusted, adjusted, and analyses stratified for seropositivity and disease activity were performed. A secondary analysis investigated 36-month outcomes.

No significant 24-month outcome differences could be found between the DMARD use categories. For seropositive patients, there was evidence of a linear trend for SF-12 PCS (p = 0.02) and EQ-5D (p = 0.01) with worse outcomes for inconsistent DMARD users. At 36 months, there was a linear trend for higher DAS28-CRP scores for inconsistent users (p < 0.01).

Overall, we found poor correlation between inconsistent DMARD use and short-term disease outcome. However, outcome in the longer term could be negatively influenced by inconsistent DMARD use, as well as short-term outcome in seropositive patients.