Obesity detrimental in ankylosing spondylitis

Obesity is tied to adverse outcomes in ankylosing spondylitis (AS), including inflammation, disease activity, physical mobility, radiographic damage, health index, liver function, and cardiovascular risk factors, a study suggests.

The researchers looked at 105 AS patients (median age, 48 years; 87.6 percent male), of which 11 (10.5 percent) had diabetes and 19 (18.1 percent) had hypertension.

Twenty-nine patients were obese (body mass index [BMI] ≥27), 36 were overweight (24≤ BMI <27), and 40 were of normal weight (18.5≤ BMI <24). Using other anthropometric measures, there were 67 obese patients according to waist circumference (WC; ≥80 cm in women and ≥90 cm in men) and 77 according to waist-to-height ratio (WHtR; ≥0.5). WHtR defined the highest number of obese patients with AS.

Obesity (BMI, WC, and WHtR) had an unfavourable influence on inflammation (C‐reactive protein [CRP]), physical mobility (Bath Ankylosing Spondylitis Metrology Index), radiographic damage (modified Stoke Ankylosing Spondylitis Spinal Score [m-SASSS]), health index (Assessment of SpondyloArthritis International Society Health Index), liver function, and blood pressure (p<0.05 for all).

Likewise, central obesity, as defined by WC and WHtR, correlated with disease activity (Ankylosing Spondylitis Disease Activity Score‐CRP; p=0.027 and p=0.025) and predicted longitudinal radiographic change (m‐SASSS; p=0.041 and p=0.045).

Central obesity was the best predictor of inflammation, disease activity, physical mobility, radiographic damage, and health index in AS. On the other hand, WHtR was the best for predicting m‐SASSS (area under the curve, 0.734; p<0.001).

Obesity conferred an increased risk of diabetes and hypertension.

The findings highlight the importance of preventing obesity in AS patients to improve their disease outcome, according to the researchers.