Study findings suggest changes in patient-reported outcomes measures were lowest among patients with psoriatic arthritis (PsA) and obesity compared to other body mass index (BMI) categories, particularly among patients who initiated tumor necrosis factor inhibitors (TNFi).

These findings were presented by Emily Purcell, MD, Rheumatology Associated, University of Pennsylvania, Philadelphia, PA, at the virtual American College of Rheumatology Convergence 2021.

“Obesity is associated with poor response to treatment in patients with PsA, however, available data are mostly focused on… [TNFi] initiators with only a few studies that have examined this association with initiators of other therapies,” explained Dr Purcell and colleagues.

This Psoriatic Arthritis Research Consortium longitudinal cohort study examined the association of obesity with change in outcome measures among patients with PsA initiating TNFi, interleukin 17 inhibitors (IL17i) and oral small molecules. The patient-reported outcome measures used to assess treatment response were the clinical Disease Activity Index for Psoriatic Arthritis (cDAPSA), Routine Assessment of Patient Index Data 3 (RAPID3), and Psoriatic Arthritis Impact of Disease (PsAID).

Patients were stratified based on BMI category: BMI 19 to <25 kg/m² (normal weight), BMI 25 to <30 kg/m² (overweight), and BMI ≥30 kg/m² (obese). Univariable and age- and sex-adjusted linear regression models were used to examine the association between BMI category and change in outcome measures.

A total of 310 patients with PsA who initiated therapy with either TNFi, IL17i, or oral small molecules and completed at least 1 follow-up visit were included in the analysis. At baseline, the mean cDAPSA was 17.3, mean PsAID was 3.6, and mean RAPID3 was 10.9.

The mean change is cDAPSA was lowest among patients with obesity (-2.91) compared to those with normal BMI (-2.29) and overweight BMI (-1.42). The mean change in RAPID3 was also lowest among patients with obesity (-0.26) compared to those with normal BMI (-1.53) and overweight BMI (-1.69). The mean change in PsAID was -0.17, -0.58, and -0.72, respectively.

Among all outcome measures, these differences were not considered statistically significant. Dr Purcell and colleagues noted this could potentially be due to sample size.

Results from unadjusted and age-and-sex adjusted analyses suggest patients with obesity had less improvement in cDAPSA, RAPID3, and PsAID compared to those with normal BMI. TNFi initiators experienced similar numerical reduction in improvement, however, there was no stepwise decrease in improvement with increasing BMI in IL17i nor OSM initiators.

“The mean change in the selected outcome measures (cDAPSA, RAPID3, PsAID) was lowest among obese patients compared to the other BMI categories,” Dr Purcell and colleagues concluded.

“Interestingly, this pattern was observed primarily among TNFi initiators as opposed to OSM or IL17i initiators,” they added.

—Janelle Bradley

Reference:
Purcell E, Reddy S, Walsh J, et al. Impact of BMI on treatment response among PsA patients initiating TNF inhibitors, IL17 inhibitors and oral small molecules. Presented at: American College of Rheumatology Convergence 2021; November 5-9, 2021; virtual. Abstract 1327.