Evaluation of insulin resistance in asymptomatic cases with positive rheumatoid factor

In the pathogenesis of autoimmune diseases, it is well established that autoantibody positivity typically precedes the clinical onset of disease by several years. In this study, we aimed to investigate the effect of inflammation potentially induced by autoimmunity on insulin resistance in asymptomatic individuals who tested positive for rheumatoid factor. This single center, case control study was conducted at SANKO University Sani Konukoğlu Practice and Research Hospital between November 2023 and November 2024. The study included asymptomatic, rheumatoid factor positive individuals presenting to the rheumatology outpatient clinic and rheumatoid factor negative asymptomatic individuals recruited from the endocrinology outpatient clinic. The case group consisted of 46 individuals who had previously been tested for rheumatoid factor due to various reasons and were found to be positive, and who had also undergone insulin resistance evaluation. The control group included 45 age and sex matched asymptomatic individuals with negative rheumatoid factor results, selected from the endocrinology clinic. Insulin resistance was detected in 29 participants (31.9%) across both groups. When analyzed separately, insulin resistance was found in 15 individuals (32.6%) in the rheumatoid factor-positive group and in 14 individuals (31.1%) in the control group (p = 0.878). Although there was a numerical difference between the groups, it was not statistically significant. The mean insulin resistance value among all participants was 2.33 ± 1.4 (median: 1.89). When evaluated by group, the mean insulin resistance value was 2.60 ± 1.6 (median: 2.07) in the rheumatoid factor-positive group and 2.05 ± 1.2 (median: 1.76) in the control group (p = 0.110). Again, although the rheumatoid factor positive group showed numerically higher values, this difference did not reach statistical significance. In conclusion, while a higher frequency of insulin resistance was observed in asymptomatic individuals with positive rheumatoid factor, the difference was not statistically significant. Nonetheless, the numerical predominance of insulin resistance in the case group suggests that rheumatoid factor positivity may play a role in triggering insulin resistance. Although these findings are promising in indicating that rheumatoid factor could be a contributing factor in the pathogenesis of insulin resistance, further research involving a more homogeneous population characterized by known duration of rheumatoid factor positivity and larger, long term studies are needed to validate these results.