Modifiable risk factors associated with the severity of rheumatoid arthritis have been studied, including the body mass index (BMI). The aim was to compare the evolution of disease activity during 24 months of follow-up in different initial BMI groups of patients with rheumatoid arthritis.
Patients were classified based on their initial BMI (normal weight, overweight, and obese). Data were collected during 24 months of follow-up. At 24 months, they were reclassified based on their BMI. The proportion of patients in each BMI category was calculated. The mean differences between the initial and final DAS-28 (Disease Activity Score 28) were calculated using the Kruskal-Wallis test. Results were stratified based on sex and age. Survival analysis and Mantel-Cox test for the achievement of sustained remission during follow-up were calculated.
A total of 269 patients were included. Most patients were at the normal weight category (n = 111). Normal weight group had the highest initial score (DAS-28, 4.01). Women present higher variability in BMI and greater disease activity compared with men. Based on age group, patients between the ages 31 and 50 years are more stable in their BMI, whereas those older than 50 years had lower BMI with time. Sustained remission was achieved by 58% of patients from the normal weight group, by 57% of patients from the overweight group, and by 42% of patients from the obese group. Survival curves of the initial normal and obese groups were significantly different (p = 0.0209).
Patients with initial obesity were less likely to achieve remission compared with patients with initial overweight or normal weight. Sex and age affects disease activity and BMI variation.