Lower Basal Metabolic Rate, Higher Charlson Comorbidity Index Predict Metabolic Syndrome in Patients With RA

Patients with rheumatoid arthritis (RA) have an approximately 11.5% annual incidence rate of metabolic syndrome, according to a study in Joint Bone Spine. Predictors of metabolic syndrome in patients with RA include lower basal metabolic rate (BMR) and higher Charlson comorbidity index scores, among other variables.

Researchers recruited 319 consecutive patients with RA from an outpatient clinic at Chonnam National University Hospital in the Republic of Korea. Only patients with RA who did not have metabolic syndrome at baseline were included in the study. Patients were followed for up to 2 years to identify the annual incidence rate of metabolic syndrome. The modified National Cholesterol Education Program/Adult Treatment Panel III 2005 for Asian populations was used to define metabolic syndrome. Univariate and multivariate logistic regression analyses were utilized to evaluate independent predictors of MetS.

In detail, a metabolic syndrome diagnosis was made if patients met ≥3 more prespecified criteria: waist circumference ≥90 cm in men or ≥80 cm in women; blood pressure ≥130/85 mmHg or use of antihypertensive drugs; fasting blood glucose ≥100 mg/dL or use of antidiabetic drugs; high-density lipoprotein cholesterol (HDL-C) ≤40 mg/dL in men or ≤50 mg/dL in women; triglycerides ≥150 mg/dL. Face-to-face interviews performed at baseline and follow-up were used to collect sociodemographic data, laboratory findings, disease activity data, and medication history.

Metabolic syndrome was diagnosed in approximately 15% (n=37) of the 247 patients with RA (median age, 58.0 years) who completed the follow-up period of 2 years. Among the entire RA cohort, the annual incidence rate of metabolic syndrome was 11.5%.

Baseline factors significantly associated with the development of metabolic syndrome included older mean age (62 vs 58 years; P =.020), higher mean BMI (24.0 vs 22 kg/m²; P =.002), increased waist circumference (84.5 vs 78.3 cm; P =.011) and waist-hip ratio (0.89 vs 0.87; P =.035), greater skeletal muscle mass (16.2% vs 3.8%; P =.005), higher body fat mass (75.7% vs 49.0%; P =.011) and percent body fat (83.8% vs 55.3%; P =.004), and greater Charlson comorbidity index scores (P <.001).

Additionally, patients with RA who developed metabolic syndrome over the 2-year follow-up period had lower BMRs at baseline compared with patients without metabolic syndrome (81.1% vs 51.9%, respectively; P =.004). Conversely, patients with RA who developed metabolic syndrome had a higher incidence of diabetes (P =.007) and hypertension (P <.001).

According to a multivariable analysis, the most consistent significant predictors of metabolic syndrome in patients with RA included BMR (odds ratio [OR], 0.205; 95% CI, 0.078–0.541; P =.001) and Charlson comorbidity index score (OR, 2.191; 95% CI, 1.280–3.751; P =.004).

Limitations of this study included its single-center design, the high loss to follow-up rate (23%), and the lack of assessment of the impact of patients’ drug interactions on metabolic syndrome.

To reduce the incidence of metabolic syndrome in patients with RA, the researchers suggest “physical activity programs combining aerobic exercise and resistance training should be implemented during early stages of RA disease.”

Reference:

Haimuzi X, Choi SE, Kang JK, et al. Basal metabolic rate and Charlson comorbidity index are independent predictors of metabolic syndrome in patients with rheumatoid arthritis [published online April 9, 2020]. Joint Bone Spine. doi: 10.1016/j.jbspin.2020.03.015