Serum interleukin‐6 receptor in polymyalgia rheumatica: A potential marker of relapse/recurrence risk

Abstract

Objective. To investigate the modulation of systemic levels of soluble interleukin-6 receptor (sIL-6R) and soluble gp130 (sgp130) in untreated and treated polymyalgia rheumatica (PMR) patients during a followup period of at least 24 months in order to evaluate the relationship of these molecules with clinical outcome and their feasibility to provide a prognostic tool in clinical practice. Methods. We analyzed sIL-6R and sgp130 serum levels in 93 PMR patients, and 46 age-matched normal controls, at disease onset and at 1, 3, 6, 12, and 24 months of followup during corticosteroid therapy by enzyme-linked immunosorbent assay. Results. No difference in sIL-6R and sgp130 levels was observed between PMR patients and normal controls at disease onset or during followup. A significant correlation was found between the number of relapses and sIL-6R concentrations at baseline and after 1, 3, and 12 months of therapy. No correlation was found between sgp130 levels and the number of relapses. Cox multivariate analysis indicated that the best model for predicting relapses was identified by sIL-6R levels and the hemoglobin value at baseline. We found that high sIL-6R levels combined with low hemoglobin values resulted in a 10.1-fold increased risk of relapse. Conclusion. Our data support the identification of a potential prognostic marker of PMR outcome that might have important implications in clinical practice. Because targeting sIL-6R with blocking antibodies has proven useful in other rheumatic disorders, our results could suggest the opportunity to evaluate sIL-6R-blocking treatment in patients with PMR and elevated levels of sIL-6R at disease onset.

Outcome Measures in Polymyalgia Rheumatica. A Systematic Review

“…The electronic search strategy yielded 868 articles, 43 of which were selected, on the basis of title and abstract, for further assessment/detailed review. Ultimately, 35 studies [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41]42,43,44,45,46 met inclusion criteria for this systematic review (Figure 1). Agreement between the 2 reviewers was 96.6% and 100% for the first and second steps of article selection, respectively.…”

“…Three are nonrandomized interventional studies or ones without clear information about randomization 24,25,26 . Longitudinal observational studies represent more than one-half of selected articles (20 of 35) [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] . One of these observational studies 36 is a longterm followup of an already included RCT 20 .…”

“…Morning stiffness. Stiffness, more commonly morning stiffness, was considered in almost all the included studies 13,14,15,16,18,19,20,21,22,24,25,26,27,28,30,33,34,35,36,37,38,40,43,44,45,46 . It was evaluated as an independent outcome in 11 studies 13,14,15,16,18,19,25,27,34,40,44 , and was included as a variable in composite disease activity scores or in the definition of relapse/recurrence/remission in an additional 15 studies 19,20,22,24,26,28,33,35,36,37,38,43,…”

“…ESR and CRP. ESR 12,13,14,15,16,17,18,19,21,22,24,25,26,27,28,30,31,33,34,35,36,37,38,39,40,43,44,45,46 and CRP 12,13,15,17,19,21,23,24,25,26,28,30,31,33,34,35,36,37,38,40,43,44,45,46 were used in the assessment of disease activity by ...…”

“…Other laboratory measures. Other laboratory outcome measures used in some observational and clinical trials include serum fibrinogen 12,15,16,45,46 and IL-6 levels 19,22,24,27,30,31,37 , mainly as experimental evaluations.…”