BMI negatively impacted nearly all components of minimal disease activity, suggesting a notable influence on patient-reported outcome measures.
Higher BMI is independently associated with lower odds of achieving minimal disease activity in psoriatic arthritis (PsA), with the strongest negative effect observed among patients treated with fixed-dose tumor necrosis factor inhibitors (TNFi), according to results of a study published in Rheumatology.
In this longitudinal observational study, researchers analyzed data from the Gladman Krembil Psoriatic Arthritis Program in Toronto, an ongoing prospective cohort established in 1978. A total of 1291 patients with at least one BMI assessment were included, while 1102 treatment courses from 582 patients initiating biologic or targeted synthetic disease-modifying anti-rheumatic drugs (DMARDs) were evaluated to determine whether BMI influenced disease activity across treatment classes.
Mean age of the study cohort was 44.7±13.0 years; 56% were men, and mean BMI was 28.8±6.36 kg/m². At baseline, 20.4% of patients had minimal disease activity. In univariable analysis, higher BMI was associated with lower odds of achieving minimal disease activity (odds ratio [OR], 0.95; 95% CI, 0.94-0.97), an association that remained significant after multivariable adjustment (OR, 0.97; 95% CI, 0.94-0.99).
Fibromyalgia, smoking, and greater radiographic damage were also associated with reduced odds of minimal disease activity, whereas male sex and TNFi use were associated with higher odds of achieving minimal disease activity. Higher BMI was significantly associated with worse tender joint counts, enthesitis, psoriasis severity, patient pain, patient global assessment, and disability, but not swollen joint counts — suggesting that obesity disproportionately affected patient-reported and subjective disease domains rather than objective inflammatory joint swelling.
These findings suggest that obesity may be an important, modifiable factor in PsA management and underscore the need to integrate weight optimization strategies alongside pharmacological therapy
Among 1102 treatment courses, higher BMI at treatment initiation was associated with reduced odds of minimal disease activity with TNFi overall (OR, 0.95; 95% CI, 0.93-0.98) and with non-weight-based TNFi after excluding infliximab in multivariable analyses (OR, 0.94; 95% CI, 0.92-0.97).
Similar findings were observed when BMI was modeled as a time-varying variable during follow-up (TNFi OR, 0.95; 95% CI, 0.92-0.97; non-infliximab TNFi OR, 0.94; 95% CI, 0.91-0.96). In contrast, BMI was not significantly associated with minimal disease activity among patients receiving infliximab, IL-17 inhibitors, IL-23 inhibitors, IL-12/23 inhibitors, or Janus kinase (JAK) inhibitors, while higher BMI was associated with greater odds of minimal disease activity with apremilast (OR, 1.08; 95% CI, 1.01-1.16).
Study limitations include the observational design with potential residual confounding and reverse causation, lack of detailed information on lifestyle and weight-modifying interventions — for example, GLP-1 receptor agonist use, bariatric surgery, or dietary programs — and limited statistical power to detect BMI-related effects in newer biologic and targeted synthetic drug classes because of smaller sample sizes
“These findings suggest that obesity may be an important, modifiable factor in PsA management and underscore the need to integrate weight optimization strategies alongside pharmacological therapy,” the researchers concluded
Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures
Mehta P, Yang M, Kharouf F, et al.Body mass index and achievement of minimal disease activity in psoriatic arthritis across different classes of advanced therapy. Rheumatology (Oxford). 2026;65(7):keag303. doi:10.1093/rheumatology/keag303
