Background Relatively few studies have assessed sustained remission over a follow up of more than three years and at multiple time points to identify predictors and consequences of remission in patients with inflammatory polyarthritis (IP) and its subset rheumatoid arthritis (RA).
Objectives To assess: i) which baseline clinical and demographic factors are associated with achieving persistent remission (PR), intermittent remission (IR) or never achieving remission (NR) in patients with IP and ii) the association between achieving PR, IR or NR on functional disability progression.
Methods Patients aged >16 yrs with recent onset IP (≥2 swollen joints lasting for >4 weeks and symptom duration <2 years) were recruited to NOAR from 2000 to 2008. Baseline variables collected included age at symptom onset, BMI, C-reactive protein (CRP), rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP) antibody, DAS28-CRP, HAQ score and self-reported comorbidities. Remission was defined as no tender or swollen joints (out of 51) and was assessed 1, 2, 3 and 5 years after baseline. Patients were classified as NR if they were not in remission at any anniversary assessment, PR if they were in remission at ≥3 consecutive anniversaries and IR otherwise. Univariate and multivariate ordinal logistic regression analyses were used to assess the association between baseline characteristics and remission group (NR was the lowest order group). A stepwise variable selection process was used to derive the multivariate model. Missing values were imputed using multiple imputation by chained equations in the multivariate model. A random effects model was used to examine the effect of remission group status on HAQ scores over time.
Results 868 patients were included in this study; 65.8% female, mean age at symptom onset 55.9 (SD 14.6) yrs and median disease duration 6.5 [IQR 4.1 to 11.1] months at baseline. The number (%) of patients achieving NR, IR and PR was 471 (54.3), 296 (34.1) and 101 (11.6), respectively. In univariate analysis, female sex, higher number of swollen or tender joints, satisfying the 2010 RA criteria, higher HAQ and DAS28-CRP scores, having at least one comorbidity, being hypertensive, depressed or obese at baseline were all associated with lower odds of being in a higher remission group (fig 1). Female sex, higher number of tender joints, CRP, DAS28, HAQ, time from symptom onset to starting DMARD treatment and being hypertensive at baseline were independently associated with lower odds of being in a higher remission group in a multivariate model. IR and PR were associated with a reduced HAQ score compared to NR (referent), adjusted β (95% CI) for IR and PR -0.51 (-0.60, -0.43), -0.85 (-0.98, -0.72) respectively, p<0.001.
Conclusions Only 11.6% of patients achieved PR during a five year follow up. As well as clinical and demographic factors, comorbidities at baseline were significantly associated with reduced probability of remission. Benefits of remission in terms of improved functional disability were seen, supporting the “treat to target” strategy.
Acknowledgements This work was supported by GlaxoSmithKline and Arthritis Research UK.
Disclosure of Interest None declared