Pain-related comorbidities and medication absence as predictors of clinical remission in RA.

Abstract

Letter to the editor: With great interest, we read the article by Wang et al. [1], about clinical remission of rheumatoid arthritis (RA). According to these findings, we contrast some of our results found in a Mexican Mestizo single cohort in a university hospital [2]. We made an observational, descriptive, retrospective, and cross-sectional study of 361 patients with RA. We analyzed variables such as demographics, rheumatoid factor and anti-cyclic citrullinated peptide antibodies presence, erythrocyte sedimentation rate, C-reactive protein, RA treatment, clinical activity, pain visual analog scale, comorbidities, and extra-articular manifestations. Clinical Disease Activity Index (CDAI) [3] was calculated. Remission was defined with a CDAI score of <2.8. Female sex was predominant (97.7 %). Mean age was 51.4 years (12.2 SD). Clinical remission was found in 145 patients (40.2 %). When patients with and without clinical remission were compared, we found significant differences in non-use of prednisone (p=0.0001), use of non-steroidal anti-inflammatory drugs (NSAIDs) (p=0.012), use of tramadol (p=0.0001), absence of osteoarthritis (OA) (p=0.33), and BMI <25 kg/m (p= 0.017) (see Table 1). In multivariate analysis, factors associated with reaching clinical remission were nonuse of oral steroids (OR 3.39 95 % CI 2.05–5.63, p= 0.0001) and absence of OA (OR 1.8, 95 % CI 1.007– 3.048, p=0.025). In contrast, negative association was found with the use of NSAIDs (OR 0.292, 95 % CI 0.117–0.73 p=0.008) and the use of tramadol (OR 0.107, 95 % CI 0.024–0.47, p=0.003). According to our study, the presence of OA in patients with RA is a factor that decreases the CDAI specificity for detecting clinical remission. This is possibly related to the score given by the patient to the visual analog scale and the presence of painful joints secondary to OA, but not inflamed by RA activity. It is therefore important that clinicians consider these factors when evaluating clinical remission in RA. These factors were not considered by the authors; we think that might explain the low remission rate; according to the median patient global visual analog scale of 5 (2.4), even the swollen joint count was lesser than the tender one in the whole cohort. Another issue could be the use of pain medication, not recorded nor analyzed. We provide another point of view when analyzing remission; although it is important to take into account these predictors in an early RA setting [4], in an established RA, joint damage could interfere with these daily practice activity indexes [5]. * D. Vega-Morales drdavidvega@yahoo.com.mx