We disclosed that low serum omentin levels were associated with obesity and AI indicative of dyslipidemia (AI ≥ 4) in axSpA patients (317.1 ± 126.8 ng/mL in obese vs. 372.3 ± 128.4 ng/mL in non-obese patients, p < 0.001, Fig. 2a; 329.5 ± 106.1 ng/mL in patients with AI ≥ 4 vs. 389.6 ± 136.9 ng/mL in patients with AI < 4, p = 0.006, Fig. 2b). Here, ITLN1 is linked to obesity due to melanocortin 4 receptor deficiency.