Early persistence on therapy impacts drug-free remission: a case-control study in a cohort of Hispanic patients with recent-onset rheumatoid arthritis

Background Medication adherence is suboptimal in rheumatoid arthritis (RA) patients and impacts outcomes. DMARD-free remission (DFR) is a sustainable and achievable outcome in a minority of RA patients. Different factors have been associated with DFR, although persistence in therapy (PT), a component of the adherence construct, has never been examined. The study's primary aim was to investigate the impact of PT's characteristics on DFR in a cohort of Hispanic patients with recent-onset RA. Methods A single data abstractor reviewed the charts from 209 early (symptoms duration <= 1 year) RA patients. All the patients had prospective assessments of disease activity and PT and at least 1 year of follow-up, which was required for the DFR definition. DFR was defined when patients achieved >= 1 year of continuous Disease Activity Score-28 joints evaluated <= 2.6, without DMARDs and corticosteroids. PT was defined based on pre-specified criteria and recorded through an interview from 2004 to 2008 and thereafter through a questionnaire. Cases (patients who achieved >= 1 DFR status) were paired with controls (patients who never achieved DFR during their entire follow-up) according to ten relevant variables (1:2). Cox regression analysis estimated hazard ratios (HRs) for DFR according to two characteristics of PT: the % of the patient follow-up PT and early PT (first 2 years of patients' follow-up). Results In March 2022, the population had 112 (55-181) patient/years follow-up. There were 23 patients (11%) with DFR after 74 months (44-122) of follow-up, and the DFR status was maintained during 48 months (18-82). Early PT was associated with DFR, while the % of the patient follow-up PT was not: HR = 3.84 [1.13-13.07] when the model was adjusted for cumulative N of DMARDs/patient and 3.16 [1.14-8.77] when also adjusted for baseline SF-36 physical component score. A lower N of cumulative DMARDs/patient was also retained in the models. Receiving operating curve to define the best cutoff of patient follow-up being PT to predict DFR was 21 months: sensitivity of 0.739, specificity of 0.717, and area under the curve of 0.682 (0.544-0.821). Conclusions DFR status might be added to the benefits of adhering to prescribed treatment.