Higher body mass index (BMI) was independently associated with lower odds of achieving minimal disease activity (MDA) in patients with psoriatic arthritis (PsA), with the effect most pronounced among those treated with tumor necrosis factor inhibitors (TNFi) other than infliximab, according to a study published in Rheumatology.1
Investigators from the Gladman Krembil PsA Program, including Pankti Mehta, MBBS, MD, DM, MS, analyzed 1291 patients from a longitudinal observational cohort followed since 1978, evaluating the association between BMI and MDA using generalized estimating equations and linear mixed models.1 Analyses adjusted for age, sex, anxiety/depression, fibromyalgia, smoking, treatment type, and radiographic damage, with subgroup analyses across 6 drug classes: TNFi, interleukin-17 inhibitors (IL-17i), IL-12/23 inhibitors (IL-12/23i), IL-23 inhibitors (IL-23i), Janus kinase inhibitors (JAKi), and phosphodiesterase-4 inhibitors (PDE4i).1
BMI and MDA achievement across the full PsA cohort
Among the 1291 patients, mean age was 44.7 years, 56% were male, and mean BMI was 28.8 kg/m².1 In unadjusted analysis, higher BMI was associated with lower odds of MDA (odds ratio [OR], 0.95; 95% CI, 0.94-0.97), an association sustained in multivariable analysis (OR, 0.97; 95% CI, 0.94-0.99).1 Fibromyalgia, current smoking, and higher radiographic damage (modified Steinbrocker score) were also negatively associated with MDA, while male sex and TNFi use were positively associated.1
Key Facts
Does higher BMI reduce the odds of minimal disease activity in PsA?
Yes. In multivariable analysis, higher BMI was independently associated with lower odds of MDA (OR, 0.97; 95% CI, 0.94-0.99), along with fibromyalgia, smoking, and radiographic damage.
Which MDA component was not affected by BMI?
Swollen joint count was the only MDA component not significantly associated with BMI, suggesting a disproportionate effect on subjective, patient-reported domains.
Does the BMI effect on MDA differ by drug class?
Yes. The negative association was significant for TNFi (excluding infliximab) but not for IL-17i, IL-12/23i, IL-23i, JAKi, or infliximab itself, which uses weight-based dosing.
Higher BMI was linked to worse outcomes across most individual MDA components, including tender joint count, total entheseal count, Psoriasis Area and Severity Index, patient pain, patient global assessment, and Health Assessment Questionnaire score, in both univariable and multivariable models.1 Swollen joint count was the only component not significantly associated with BMI.1 Anxiety/depression, osteoarthritis, and apremilast use were not significantly associated with MDA in the full-cohort model.1
BMI-MDA association differs across advanced therapy classes
The drug-class analysis included 1102 treatment courses from 582 patients: 433 on TNFi (80 with infliximab), 166 on IL-17i, 71 on IL-23i, 64 on IL-12/23i, 32 on JAKi, and 57 on PDE4i.1 In multivariable analysis, higher BMI at drug initiation was associated with reduced odds of MDA for TNFi overall (OR, 0.95; 95% CI, 0.93-0.98) and TNFi excluding infliximab (OR, 0.94; 95% CI, 0.92-0.97).1 No significant association was seen for infliximab alone, IL-17i, IL-12/23i, IL-23i, or JAKi.1
Higher BMI was associated with better odds of MDA among patients treated with apremilast (OR, 1.08; 95% CI, 1.01-1.16).1 Longitudinal, time-varying BMI assessment produced consistent results, with reduced MDA odds for TNFi overall (OR, 0.95; 95% CI, 0.92-0.97) and TNFi excluding infliximab (OR, 0.94; 95% CI, 0.91-0.96), and no significant association for the other drug classes.1 The investigators noted infliximab's weight-based dosing may mitigate the BMI-related pharmacokinetic attenuation seen with fixed-dose TNFi agents.1
The findings align with earlier data from the same center, where obesity was associated with roughly half the odds of achieving sustained MDA over 12 months, driven by cutaneous psoriasis and patient-reported outcomes rather than swollen joint count.2 The investigators noted sample sizes for newer drug classes were smaller, limiting power to detect BMI effects, and cautioned the absence of a significant association in those groups should not be interpreted as evidence of no effect.1 They pointed to emerging incretin-based weight-modifying therapies, including glucagon-like peptide-1 receptor agonists, as a potential adjunctive strategy warranting prospective study in PsA.1
References
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
Eder L, Thavaneswaran A, Chandran V, Cook RJ, Gladman DD. Obesity is associated with a lower probability of achieving sustained minimal disease activity state among patients with psoriatic arthritis. Ann Rheum Dis. 2015;74:813-817. doi:10.1136/annrheumdis-2013-204448
