Serum level of adiponectin is a surrogate independent biomarker of radiographic disease progression in early rheumatoid arthritis: results from the ESPOIR cohort

Introduction: Adipokines such as adiponectin, leptin, and visfatin/nicotinamide phosphoribosyltransferase (NAMPT) have recently emerged as pro-inflammatory mediators involved in the pathophysiology of rheumatoid arthritis (RA). We aimed to determine whether serum adipokine levels independently predicted early radiographic disease progression in early RA. Methods: In total, 791 patients were included from the prospective Etude et Suivi des POlyarthrites Indifferenciees Recentes (ESPOIR) cohort who met the American College of Rheumatology-European League Against Rheumatism criteria for RA (n = 632) or had undifferentiated arthritis (UA) (n = 159). Enzyme-linked immunosorbent assay (ELISA) was used to assess baseline serum levels of adiponectin, leptin, and visfatin/NAMPT. In the RA group, we tested the association of serum adipokine levels and (a) baseline radiographic damage and (b) radiographic disease progression, defined as a change >0 or >= 5 in total Sharp-van der Heijde Score (Delta SHS) between inclusion and 1 year (Delta SHS >= 1 or rapid radiographic progression: Delta SHS >= 5), adjusting for confounders (age, sex, body-mass index, insulin resistance, C-reactive protein level, Disease Activity Score in 28 joints, Health Assessment Questionnaire score, autoantibody status, steroid use, and radiographic evidence of RA damage at inclusion). Results: Adiponectin level was independently associated with baseline total Delta SHS (adjusted beta = 0.12; P = 0.006). It was also associated with Delta SHS >= 1 (adjusted odds ratio (aOR) = 1.84 (1.25 to 2.72)) involving erosive as well as narrowing disease progression (aOR = 1.73 (1.17 to 2.55) and 1.93 (1.04 to 3.57), respectively). Serum adiponectin level predicted Delta SHS >= 5 (aOR = 2.0 (1.14 to 3.52)). Serum leptin level was independently associated only with Delta SHS >0 (aOR = 1.59 (1.05 to 2.42)). Conversely, serum visfatin/NAMPT level and radiographic disease progression were unrelated. Considering the receiver-operated characteristic curves, the best adiponectin cut-offs were 4.14 mu g/ml for Delta SHS >= 1 and 6.04 mu g/ml for Delta SHS >= 5, with a good specificity (58% and 75% for Delta SHS >= 1 and Delta SHS >= 5, respectively) and high negative predictive values (75% and 92% for Delta SHS >= 1 or Delta SHS >= 5, respectively). Conclusion: Serum adiponectin level is a simple useful biomarker associated with early radiographic disease progression in early RA, independent of RA-confounding factors and metabolic status.