THE IMPLICATION OF SERUM CALCIUM-PHOSPHORUS RATIO TO ASSESS RHEUMATOID ARTHRITIS (RA) IN WOMEN OF TRIPURA, A NORTH-EASTERN STATE OF INDIA

Shukdeb Acharjee M.Sc, Avik Sarkar Ph.D, Chandan Raybarman M.D, Chinmoy Ghosh Ph.D, and
Surajit Bhattacharjee Ph.D*

ABSTRACT

Background: Systemic inflammation during rheumatoid arthritis (RA) affects multiple organs and metabolic pathways. Interleukin-18 (IL-18) and tumour necrosis factor-alpha (TNF-α) are the novel cytokines in RA, which mediate synovial inflammation and articular manifestations through the modulation of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa β Ligand (RANKL) expression. This might be reflected into serum calcium to phosphorus ratio (Ca/P) of RA patients. In this context, our present study investigates the role of serum Ca/P in the assessment of systemic inflammation in treatment-naive RA patients. Methods: This cross-sectional study (2017-2019), conducted at Tripura, India, included 146 RA women (duration ≤15 months) and 40 age and gender-matched healthy control (HC). All participants were divided into pre-menopausal (PreM) and post-menopausal (PostM) group. We measured serum Ca, P, IL-18, TNF-α, OPG, and RANKL in all patients and HC. Pearson’s bivariate correlation(r) and partial correlation (pR) analysis were performed to correlate Ca/P with IL-18, TNF-α and OPG to RANKL ratio (OPG/RANKL). Results: Serum Ca/P was found to be negatively correlated with IL-18 (PreM, r=-0.68, p=0.01; pR=-0.54, p=0.01 and PostM, r=-0.53, p=0.01; pR=-0.66, p=0.01) and TNF-α (PreM, r=-0.56, p=0.01; pR=-0.45, p=0.01 and PostM, r=-0.66, p=0.01; pR=-0.51, p=0.01). On contrary, significant positive correlation was observed between Ca/P and OPG/RANKL (PreM, r=-0.81, p=0.01; pR=-0.73, p=0.01 and PostM, r=-0.77, p=0.01; pR=-0.68, p=0.01). Conclusions: The study highlights a strong association between Ca/P and systemic inflammation in RA. This implicates that Ca/P could be used as a marker for the real-time evaluation of RA.

Keywords: Ca/P; cytokines; OPG/RANKL; Osteoprotegerin; Rheumatoid Arthritis.