Article Text
Abstract
Objectives The aim of this paper was to analyse the impact of obesity, in addition to known predictors, on disease outcome in early rheumatoid arthritis (RA).
Methods Body mass index (BMI) was available in 260 patients from the Swedish pharmacotherapy trial (SWEFOT). Differences in disease activity (DAS28), functional impairment (HAQ), pain (Visual Analogue Scale, VAS-pain) and radiographic damage were evaluated over 24 months between BMI categories (obese BMI >30, n=43; overweight BMI=25–29.9, n=74; normal BMI <25, n=143) using non-parametric testing. Predictors of European League Against Rheumatism non-remission (DAS28 ≥2.6) at 24 months of follow-up were evaluated using binary univariate and multivariate logistic regression.
Results Obesity at baseline was associated with worse continuous-scale clinical outcomes over 24 months (DAS28, HAQ and VAS-pain at last visit: obese vs normal: p<0.001; obese vs overweight: p<0.05). Furthermore, obese patients compared with non-obese patients had significantly greater odds of non-remission at 24 months (adjusted OR (aOR) 5.2; 95% CI 1.8 to 15.2). Other independent predictors were female sex (aOR 2.6; 95% CI 1.1 to 5.8), current smoking (aOR 2.6; 95% CI 1.1 to 6.3) and HAQ (per-unit increase, aOR 1.9; 95% CI 1.1 to 3.4). The pattern was similar among seropositive and seronegative patients; and in the subgroups of methotrexate responders and patients randomised at 3 months to add-on of sulfasalazine+hydroxychloroquine, although not significant with add-on of infliximab. Obesity had no independent association to radiographic progression.
Conclusions In this early RA trial reflecting today’s standard treatment, obesity, in addition to sex, smoking and functional impairment strongly lowered the chance of attaining good clinical outcomes, including remission, today’s treatment goal. This highlights the importance of considering lifestyle modification as one of the cornerstones of RA care.
Trial registration number NCT00764725; Post-results. WHO database at the Karolinska University Hospital: CT20080004.
- early rheumatoid arthritis
- disease activity
- DMARDs (synthetic)
- anti-TNF
- treatment
- body mass index
- predictions and projections
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Footnotes
Contributors All authors meet the ICMJE guidelines for authorship and contributed equally to the design of the project, the discussion of the results and to the preparation of the manuscript. All authors read and approved the final version of the manuscript. AL conducted the statistical analyses, data management and preparation of the manuscript under the supervision of SS. KH and CL contributed to statistical analysis discussion and data management. KB and IH contributed with medical expertise in the project discussion. AL and SS created and finalised all graphical preparations. SS and RFvV were in charge of project supervision.
Competing interests AL, KB, IH, KH, CL and SS have no conflicts of interest to disclose; RFvV has received grants/research support from AbbVie, BMS, GSK, Pfizer, Roche and UCB—and has received consultancy fees from AbbVie, Biotest, BMS, Crescendo, GSK, Janssen, Lilly, Merck, Pfizer,Roche, UCB and Vertex outside the submitted work.
Ethics approval The regional Swedish ethics committees of all participating SWEFOT sites.
Provenance and peer review Not commissioned; externally peer reviewed.