TOPLINE

Among patients with spondyloarthritis (SpA) including those with axial spondyloarthritis (axSpA) or psoriatic arthritis (PsA), obesity was common and was associated with poorer physical performance, whereas sarcopenia was rare. Higher levels of daily physical activity were independently associated with better muscle-related body composition, grip strength, and physical performance.

METHODOLOGY

• Researchers conducted a cross-sectional study to describe phenotypes of body composition of adults with SpA and their associations with physical performance and daily activity.
• A total of 213 patients with SpA (140 with axSpA and 73 with PsA) were recruited at a German tertiary centre between September 2023 and April 2024; of these, 59.6% were treated with TNF inhibitors and 40.4% were treated with conventional therapy.
• Physical performance was evaluated using gait speed over 4 m, the Short Physical Performance Battery (SPPB), and the Axial Spondyloarthritis Performance Index (ASPI). Handgrip strength was also assessed.
• Daily physical activity was assessed using a questionnaire, and scores were used to categorise patients into tertiles representing low, moderate, and high activity.
• Obesity was defined using DEXA-derived body fat percentage (≥ 30% in men and ≥ 40% in women); BMI ≥ 30 was also recorded. Sarcopenia was assessed using the ratio of appendicular lean mass to BMI (ALM/BMI) and low grip strength.

TAKEAWAY

• DEXA-defined obesity was observed in 52.5%-62.5% of men and 51.9%-65.9% of women across SpA subgroups, whereas sarcopenia was uncommon (0%-6.3%).
• Obesity was associated with poorer physical performance, including longer ASPI total times in both men (P < .01) and women (P = .04) and lower SPPB total scores in men (P < .01).
• Higher levels of daily physical activity were associated with a lower fat mass index, a higher ALM/BMI, better SPPB performance, a lower prevalence of reduced grip strength, and faster ASPI performance (P < .05 for all). ALM/BMI, grip strength, and ASPI performance remained independently associated with daily physical activity after adjusting for relevant variables (P < .05 for all).
• Men who received TNF inhibitors had lower body fat percentages and a lower prevalence of DEXA-defined obesity than those who received conventional therapy (P ≤ .01 for both). No comparable differences were observed in women.

IN PRACTICE

"[The findings suggest that] obesity appears to be the dominant body composition phenotype associated with impaired physical performance, whereas sarcopenia was uncommon in this relatively young SpA cohort," the authors of the study wrote.

SOURCE

The study was led by Uta Kiltz, Rheumazentrum Ruhrgebiet, Herne, Germany. It was published online on September 26, 2026, in Rheumatology.

LIMITATIONS

The cross-sectional design prevented causal inference and could not exclude reverse causation. Physical activity was self-reported and may have been subject to recall and social desirability bias. The low prevalence of sarcopenia limited subgroup analyses.

DISCLOSURES

The study received funding from Fresenius Kabi Germany. Several authors reported having financial ties such as receiving consulting fees or research support and/or serving on scientific advisory boards of various pharmaceutical companies including Fresenius Kabi.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.