Background Biological therapies had greatly improved the treatment of rheumatoid arthritis (RA). The response to biologics may be influenced by many factors. Little is known about the impact of body composition inRA biologics.
Objectives We aimed to investigate the impact of obesity (BMI≥30) andbody composition (lean mass/ fat mass)on response to biotherapy in RA.
Methods A retrospective study was performed over a period of 11 years (2006–2016). Patients diagnosed RA (according to the ACR 1987 criteria) and treated by biologics were enrolled. Body composition (lean mass/ fat mass) was measured by X-ray biphotonic absorption (DXA). The threshold of signification was set for a value of p<0.05.
Results Fifty patients were enrolled, including 5 men and 45 women (sex ratio=0.11). The mean age was 66 years [38–79]. The mean duration of RA was 5 years [1–30]. The mean duration of treatment with biologics was 38 months [6–120]. Thirty nine patients were treated by TNF alpha inhibitors (25 etanercept, 7 adalimumab, 6 infliximab and 1 certolizumabpegol), 6 rituximab and 5 tocilizumab. Nine patients had a normal weight (18%), 17 had overweight (34%) and 24 had obesity (49%). The average percentage of fat mass was 44.8 [23–54], with a median of 46. While comparing obese patients with others, we did not notice a significant difference in the mean variation of the DAS28 at 6 months for TNF alpha inhibitors nor for all biotherapies combined (respectively p=0.6 and p=0.9). The same result was observed while comparing the DAS28 according to the body composition (relative to the median of the percentage of the fat mass: for TNF alpha inhibitors (p=0,6) and for all biotherapies combined (p=0,09)).
Conclusions In our study, there was no change in response to biologics in patients with RA. Further prospective studies with a larger size will be required to confirm or reverse these results.
Iannone F, Lopalco G and al. Impact of obesity on the clinical outcome of rheumatologic patients in biotherapy. Autoimmun Rev. 2016 May;15(5):447–50. doi: 10.1016.
Gardette A, Ottaviani S. Body mass index and response to tocilizumab in rheumatoid arthritis: a real life study. Clin Rheumatol. 2016 Apr;35(4):857–61. doi: 10.1007.
Disclosure of Interest None declared