Increased insulin resistance in rheumatoid arthritis

(HealthDay)—Patients with rheumatoid arthritis (RA) have elevated insulin resistance (IR), but this is not associated with increased atherosclerosis risk, according to a study published online Dec. 10 in Arthritis & Rheumatology.

Jon T. Giles, M.D., M.P.H., from Columbia University in New York City, and colleagues compared IR (estimated using the homeostatic model [HOMA-IR]) between 95 RA patients and 98 demographically-matched non-RA controls.

The researchers found that the average HOMA-IR levels were 31 percent higher in the RA group, regardless of strata of demographic or cardiometabolic risk factors. In the control group, HOMA-IR was strongly and significantly associated with C-reactive protein and interleukin-6, but this association was weaker in the RA group. Higher HOMA-IR correlated with rheumatoid factor positivity in men and women, and with prednisone use in women, among those with RA. Higher HOMA-IR correlated with all assessed subclinical atherosclerosis measures in the control group before adjustment; after adjustment for cardiovascular risk factors, the correlations were attenuated and were no longer statistically significant. Over an average of 3.2 years of follow-up, neither baseline nor average HOMA-IR correlated with change in any measures of atherosclerosis among the RA patients.

"Although IR was higher in RA than in non-RA controls, higher levels may not independently impart additional atherosclerosis risk," the authors write.