Associations of circulating total p-cresylsulfate and indoxyl sulfate concentrations with central obesity in patients with stable coronary artery disease: sex-specific insights

Elevated systemic inflammation, common in obesity, increases cardiovascular disease risk. Obesity is linked to a pro-inflammatory gut microbiota that releases uremic toxins like p-cresylsulfate (PCS) and indoxyl sulfate (IS), which are implicated in coronary atherosclerosis, insulin resistance, and chronic kidney disease. This study examines the relationship between total PCS and IS levels and central obesity in patients with stable coronary artery disease (CAD). A cross-sectional study was conducted on 373 consecutive patients with stable CAD from a single center. Serum levels of total PCS and IS were measured using an Ultra Performance LC System. Central obesity was evaluated using a body shape index (ABSI) and conicity index (CI). Six obesity-related proteins were also analyzed. Structural equation modeling (SEM) assessed direct and indirect effects of total PCS, IS, and the six obesity-related proteins on central obesity. Significant positive correlations were found between total PCS and IS with waist-to-hip ratio (WHR) (r = 0.174, p = 0.005 for total PCS; r = 0.144, p = 0.021 for IS), CI (r = 0.273, p < 0.0001 for total PCS; r = 0.260, p < 0.0001 for IS), and ABSI (r = 0.297, p < 0.0001 for total PCS; r = 0.285, p < 0.0001 for IS) in male patients, but not in female patients. Multivariate analysis showed higher odds ratios (ORs) for elevated CI (OR = 3.18, 95% CI: 1.54–6.75, p = 0.002) and ABSI (OR = 3.28, 95% CI: 1.54–7.24, p = 0.002) in patients with high PCS levels, and elevated CI (OR = 2.30, 95% CI: 1.15–4.66, p = 0.018) and ABSI (OR = 2.22, 95% CI: 1.07–4.72, p = 0.033) in those with high IS levels, compared to those with low toxin levels. SEM analysis indicated that total PCS and IS directly impacted central obesity indices and indirectly influenced central adiposity measures like WHR through high sensitivity C-reactive protein (hs-CRP) (β = 0.252, p < 0.001). Circulating total PCS and IS contribute to central obesity in male patients with stable CAD, partially mediated by hs-CRP.