Adiponectin is negatively associated with disease activity and Sharp score in treatment-naïve Han Chinese rheumatoid arthritis patients

The association and potential role of the protein hormone adiponectin in autoimmune diseases causing musculoskeletal disorders, including rheumatoid arthritis (RA), are controversial. Conflicting results may arise from the influences of confounding factors linked to genetic backgrounds, disease stage, disease-modifying anti-rheumatic drugs and patients' metabolic characteristics. Here, we examined serum level of adiponectin and its relationship with disease activity score 28 with erythrocytes sedimentation rate (DAS28[ESR]) and Sharp score in a treatment-naïve Han Chinese RA population. This cross-sectional study enrolled 125 RA patients. Serum level of total adiponectin was assessed by enzyme-linked immunosorbent assay (ELISA). Other important clinical and laboratory parameters were collected from the hospital database. DAS28(ESR) was calculated according to the equation previously published. Sharp score was evaluated based on hands radiographs by an independent radiologist. The correlation between serum adiponectin level and DAS28(ESR) or the Sharp score was investigated by univariate and multivariable linear regression analyses, respectively. Multiple imputation by chained equations was used to account for missing data. Univariate analyses showed a significant positive correlation between DAS28(ESR) and age or C-reactive protein (CRP) (both p = 0.003), while serum adiponectin level was negatively correlated with DAS28(ESR) (p = 0.015). The negative correlation between adiponectin level and DAS28(ESR) remained true in multivariable analyses adjusted for confounders. In addition, the univariate analyses revealed positive correlations of Sharp score to disease duration (p < 0.001), CRP (p = 0.023) and ESR (p < 0.001). In the multivariable model adjusted for confounders, adiponectin was negatively correlated with Sharp score (p = 0.013). In this single-institution cross-sectional study, serum adiponectin level in treatment-naive RA patients is negatively correlated with DAS28(ESR) and the Sharp score after adjustment for prominent identified confounders. Serum adiponectin may be potentially useful for assessing disease activity and radiographic progression of RA.