Resumen
Introduction: This study aims to assess the status of serum vitamin D, parathyroid hormone, type II collagen, calcium, phosphate, albumin, and alkaline phosphatase in osteoarthritis and rheumatoid arthritis patients and to study their association with rheumatoid arthritis disease activity. Materials and Methods: This prospective cross-sectional study was conducted at the clinical analysis department, College of Pharmacy, Hawler Medical University in 2017. They study samples were collected at Rizgary Teaching Hospital during the period September 2015 to January 2016. A total of (N=156) participants were included: (N=53) patients with rheumatoid arthritis (RA), (N=53) with osteoarthritis (OA), and (N=50) healthy controls. Enzyme Linked Immuno Sorbent Assay kits determined serum vitamin D, parathyroid hormone, and type II collagen; and serum albumin, calcium, phosphate and alkaline phosphatase, were determined by standard colorimetric methods. Results and Discussion: Statistically significant higher levels of parathyroid hormone and type II collagen, with lower levels of Vitamin D, were found in the osteoarthritis group than the rheumatoid arthritis group and the healthy controls (P=0.007, P<0.001, P= 0.005) respectively. Multiple linear regression showed a statistically significant difference in serum type II collagen as a dependent variable, in patients suffering from RA or OA compared to the healthy control group; after adjusting for the effect of other independent study variables, there was a mean increase of (45.90 nmol/L, P<0.001) in RA patients, and OA patients showed greater levels of type II collagen (73.950 nmol/L) than the health control group (P<0.001). Conclusions: Elevated type II collagen levels, in conjunction with a low vitamin D status, may be strong discriminator between osteoarthritis and rheumatoid arthritis patients.