Psoriatic Arthritis
FRI0075 Obesity is an Independent Contributor to Functional Capacity and Inflammation in Rheumatoid Arthritis and Psoriatic Arthritis
JM Kremer and G Reed.
Body composition is altered in rheumatoid arthritis (RA) and possibly psoriatic arthritis (PsA) and may play important differential effects on disease outcomes. Here, Kremer et at describe body composition characteristics of a large multicenter cohort of North American RA and PsA patients and examine the associations of body mass index (BMI) on disease activity and disability.
Methods: Subjects enrolled in CORRONA, a large prospective multicenter database of North American RA and PsA patients cared for in community practice, have periodic collection of demographic and disease specific data. The proportion of subjects meeting WHO criteria for underweight (BMI < 18.5), normal weight (BMI 18.5 - < 25), overweight (BMI 25 - < 30), and obese (BMI > 30) were calculated for RA and PsA subjects. The effects of BMI category on disease activity and functional capacity were calculated, with adjustment for pertinent confounders.
Results: 11,323 RA and PsA patients were included. Of these, 110 (1%) were classified as underweight, 2285 (20.2%) were normal weight, 3102 (27.4%) were overweight, and 3566 (31.5%) were obese. Compared to the normal weight group, overweight and obesity were associated with significantly higher MHAQ, DAS28, Patient Global Assessment of Disease, CRP, and ESR.
| Difference in Overweight vs. Normal weight | p | Difference in Obese vs. Normal weight | p | |
| MHAQ | 0.12 | 0.12 | 0.12 | <0.001 |
| DAS28 | 0.13 | 0.037 | 0.35 | <0.001 |
| Patient Global Assessment | 1.4 | 0.04 | 5.7 | <0.001 |
| CRP (log transformed) | 0.14 | 0.04 | 0.39 | <0.001 |
| ESR (log transformed) | 0.10 | 0.016 | 0.24 | <0.001 |
Conclusions: Increasing BMI is associated higher disease activity, functional disability, and systemic inflammation in RA and PsA subjects.
Editorial Comment: These findings are in stark contrast to those presented in OP0116, in which increasing BMI was associated with less radiographic progression over time. The basis for these differences is not immediately clear. However, it could indicate that with increasing BMI, standard ways of estimating RA disease activity and severity (e.g. DAS, ESR, CRP, and HAQ) may not accurately represent damage and destruction occurring at the level of the joint. Further work is needed to establish whether obesity-adjusted outcome measures are required to accurately evaluate disease in these patients.