Background Metabolic syndrome (MetS), a cluster of cardiovascular risk factors, is common manifestation of RA. However, whether MetS is more prevalent in patients with rheumatoid arthritis (RA) as compared to the general population is somewhat compelling, especially in Asians.
Objectives To compare the frequency of MetS and the magnitude of insulin resistance measured by homeostasis model assessment for insulin resistance (HOMA-IR) between South Korean women with RA and healthy subjects and to evaluate risk factors for the presence of MetS and increased HOMA-IR in RA patients.
Methods In a cross-sectional setting, 84 female patients with RA and 109 age-matched female healthy subjects were consecutively recruited at the university affiliated rheumatology center in South Korea from January 2008 to December 2009. Mets was defined according to the Third report of the National Cholesterol Education Program’s Adult Treatment Panel (NCEP-ATP III) 2004 using the Asian criteria for central obesity when 3 or more of the following components were presents: 1) increased waist circumference to ≥80 cm in women, 2) elevated blood pressure to ≥130/85 mmHg or requiring drug therapy, 3) elevated serum TG level to ≥150 mg/dl, 4) reduced serum HDL-C to ≤50 mg/dl in women, and 5) elevated fasting glucose level to ≥100 mg/dl or requiring drug therapy.
Results No significant difference in the frequency of MetS between RA patients (19%) and healthy subjects (15.6%) was demonstrated (p=0.566), whereas RA patients has a higher HOMA-IR than healthy subjects (median 1.27 versus 0.73, p<0.001). RA patients met the NCEP-ATP III 2004 criteria for high blood pressure more often than healthy subjects (44% versus 19.3%, p<0.001), whereas low high density lipoprotein cholesterol (HDL-C) was more prevalent in healthy controls than patients with RA (33% versus 14.3%, p=0.004). Longer disease duration tended to be predictive of MetS in RA patients, but did not remain statistically significant in multivariable logistic regression model (OR=1.01, 95% CI=1.00-1.02, p=0.084). Meanwhile, higher serum C-reactive protein (CRP) and the Disease Activity Score assessed by using 28-joint counts for swelling and tenderness-erythrocyte sedimentation ratite (DAS28-ESR) significantly contributed to increased HOMA-IR in RA patients after adjusting age, body mass index and triglyceride (CRP; β=0.100, SE=0.053, p<0.001, DAS28-ESR; β=0.134, SE=0.063, p=0.036).
Conclusions Apart from increased insulin resistance, the frequency of MetS in South Korean women with RA was not significantly higher than in healthy subjects. Despite no obvious risk factors for the presence of MetS were found, inflammation (CRP) and disease activity (DAS28-ESR) significantly contributed to increased insulin resistance in RA patients in the present study.
Sidiropoulos PI, Karvounaris SA, Boumpas DT. Metabolic syndrome in rheumatic diseases: epidemiology, pathophysiology, and clinical implications. Arthritis Res Ther. 2008;10(3):207.
Disclosure of Interest None Declared