Impact of Weight Loss on Rheumatoid Arthritis Disease Activity, Biomarkers

Weight loss was associated with improved rheumatoid arthritis (RA) outcomes in patients with obesity, according to study results published in Rheumatology.

Researchers conducted a proof-of-concept, 12-week, randomized controlled trial of patients with a clinical diagnosis of RA, a body mass index (BMI) of at least 30 kg/m², and evidence of power Doppler synovitis.

A total of 40 patients were randomly assigned to either a diet condition (n=20) or the control condition (n=20). Patients in the diet condition were assigned a hypocaloric diet of 1,000 to 1,500 kcal/d with high protein meal replacements. Patients in the control condition were provided with basic diet suggestions but no caloric goal. The primary outcomes were improvements from baseline to week 12 in Disease Activity Score-28 joint count (DAS-28) and 34-joint power Doppler ultrasonography (PDUS) score. The Health Assessment Questionnaire-Disability Index (HAQ-DI) was used to assess the impact of the diet intervention on disease activity and patient functioning. Serum levels of multiple biomarkers were measured at baseline and follow-up.

Baseline demographic and clinical characteristics were comparable between study groups. In the total cohort, mean age was 55.0±13.2 years; 90.0% were women; 75.0% were White; and 80.0% had seropositive RA. At baseline, mean BMI was 34.8±5.7. At 12 weeks, patients in the diet intervention had lost an average of 9.5 kg each, compared with just 0.5 kg in the control condition (P <.001). The mean DAS28 score in the diet group decreased significantly, from 5.2±1.2 at baseline to 4.2±1.2 at 12 weeks (P <.001). While a slight reduction was observed in the control group, the difference was not significant (4.7±1.0 to 4.4±1.2; P =.16). The PDUS score had a numerically greater reduction in the diet group (20.8±10.8 to 13.1±9.1; P <.001) compared with the control group (16±11.8 to 12.3±12.1; P =.01), though the between-group difference was not significant.

Patient-reported pain and functioning improved over time in the diet group. Additionally, HAQ-DI scores decreased significantly during the 12-week diet intervention (0.8 to 0.6; P =.04). Commensurate decreases in pain, functioning, and HAQ-DI scores were not observed in the control condition. Serum leptin levels decreased over the 12 weeks in the intervention group (P =.009), but not in the control group. While adiponectin levels did not change significantly over time in either group, they were higher at 12 weeks in the intervention group compared with the control group (P =.037).

Limitations of the study included the small cohort size and short follow-up period. Additional research is necessary to elucidate the effects of long-term weight loss on RA activity.

The study authors concluded, “Further study is required to validate these findings, but the results are encouraging that a dietary intervention may serve as a helpful adjunctive treatment for RA.”

Reference

Ranganath VK, La Cava A, Vangala S, et al. Improved outcomes in rheumatoid arthritis with obesity after a weight loss intervention: randomized trial. Rheumatology (Oxford). Published online May 28, 2022. doi:10.1093/rheumatology/keac307