Obesity epidemic and rheumatoid arthritis

The global obesity epidemic was issued with a further health warning today that obesity exacerbates the quality of life of patients with rheumatoid arthritis (RA).

New data presented at EULAR 2007, the Annual European Congress of Rheumatology in Barcelona, Spain, shows that RA in obese patients is associated with worse quality of life outcomes on four key levels: pain, fatigue, physical function and overall utility scores.

In a study of 1041 patients with RA, undertaken Diakonhjemmet Hospital, Oslo, obese participants (OB) reported significantly increased ratings for pain and fatigue than normal weight (NW) participants (Pain: AIMS2 OB 5.47 vs. NW 4.53, p=0.001. Fatigue VAS: OB 53.3 vs. NW 45.4, p=0.015). Obese patients also rated significantly worse physical functioning than normal weight patients (SF-36: OB 43.6 vs. NW 55.6, p=< 0.001).

Lead author of the research Dr Siri Lillegraven commented: It seems that obesity has an impact on a patient's quality of life and on the self-perceived burden of RA. In the key areas highlighted by this study, RA patients with concurrent obesity scored significantly worse in the quality of life assessments than normal weight patients."

Key areas of self-reported health status (HAQ, MHAQ, SF-36 and AIMS2) and visual analogue scales (VAS) for pain, fatigue and disease activity were used in the study, and patients were grouped according to Body Mass Index (BMI). BMI was classified into normal weight, overweight and obesity. Underweight patients (BMI < 18) were excluded from the study.

Of the 1041 patients sampled, 53.8% (541) fell into the normal weight category, 33% (316) were considered overweight and 10.6% (102) fell into the obese category. Overall, patient groups were compared using ANOVA and linear regression.

The robustness of the study's findings is supported by consistent results across different instruments measuring the same dimensions and a recent report from a Peruvian group (Garca-Poma et al, March 2007, Clinical Rheumatology). Furthermore, the observed associations remain significant when corrected for age, gender, rheumatoid-factor status and smoking.