To determine if
obesity is associated with poorer patient-reported outcomes (PROs) in patients with
axial spondyloarthritis (
axSpA), we conducted a cross-sectional study using data of the PRESPOND registry from a tertiary referral center in Singapore between 2011 and 2015. Demographics, clinical, and PRO variables were collected. Patients were divided into three categories: normal (BMI < 23 kg/m2),
overweight (23 kg/m2 ≤ BMI < 27.5 kg/m2) and obese (BMI ≥ 27.5 kg/m2), using Asian BMI classification. The dependent variables are
Pain score, Bath
Ankylosing Spondylitis Patient Global Score (BAS-G), Bath
Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath
Ankylosing Spondylitis Functional Index (BASFI), Health Assessment Questionnaire (
HAQ), and Medical Outcomes Study Short Form 36 version 2 (SF-36). Multivariate regression analyses were performed with these dependent variables and
obesity categories, adjusting for confounders. Among 194 patients with
axSpA, 32% are
overweight while 22% are obese. We found that obese patients had significant poorer
pain (β: 11.87, 95%CI 2.13, 21.60) and BAS-G scores (β: 10.18, 95%CI 1.59, 18.76) when compared to normal BMI patients. However,
obesity was not associated with BASDAI (β 0.50, 95%CI -0.22, 1.22), BASFI (β 0.08, 95%CI -0.66, 0.81),
HAQ (β -0.07, 95%CI -0.21, 0.06), physical component summary (β -0.02, 95%CI -4.47, 4.44), and mental component summary (β -2.85, 95%CI -7.57, 1.88) of SF-36.
Obesity was associated with
pain score and BAS-G but not with BASDAI, BASFI,
HAQ, and SF-36. Further study is needed to examine the causal relationship between
obesity and poorer PROs.