Fasting Blood Glucose, Body Mass Index and Waist Circumference in Patients with Rheumatoid Arthritis

Background: The goal was to assess patterns of Fasting Blood Glucose (FBG), Body Mass Index (BMI), and Waist Circumference (WC) in Rheumatoid Arthritis (RA).

Methods: This was a cross-sectional study carried out on 142 RA patients. Demographics, disease characteristics, lifestyle factors, FBG, BMI, and WC were collected. A convenient sampling method was employed. Multivariable linear regression model and multivariable Generalized Additive Model (GAM) were built after application of backward elimination to explore the relationship between FBG/BMI/WC and risk factors. The predicted smooth functions and 95% confidence intervals were plotted in multivariable GAM models. P<0.05 was significant. All analyses used R Statistical Software.

Results: 82% of patients were females. Mean (SD) age was 52 (13) years. The prevalence of prediabetic FBG and diabetic FBG were 27% and 19%, respectively. A significant association was observed between FBG and adalimumab (β=0.77, 95%CI, 0.32 to 1.21, P=0.001), hydroxychloroquine (β=-11.19, 95%CI, -0.54 to -21.84, P=0.04) and wake-up time on weekends (β=-2.72, 95%CI, -5.26 to -0.17, P=0.04). The prevalence of overweight and obese BMI was 32% and 39%, respectively. Sleep duration on weekdays (EDF=1.37, P<0.04) and smoking (β=-0.17, P=0.04) were associated with BMI. The prevalence of abdominal obesity was 48% and it was associated with sleep duration on weekdays (EDF=2.00, P<0.005). Gender modified the relationship of sleep duration and BMI/WC.

Conclusion: In RA patients, adalimumab and late wake-up time on weekends were risk factors for FBG while hydroxychloroquine was protective. In female patients, sleep duration was associated with BMI and WC and smoking was associated with BMI.