Inflammatory–metabolic burden and its correlates in patients with gout: a case–control study

Aims: To evaluate cumulative advanced glycation end product accumulation measured by skin autofluorescence (AGE-SAF) in patients with gout and to investigate its associations with inflammatory burden, renal function, metabolic parameters, and the C-reactive protein–albumin–lymphocyte (CALLY) index. Methods: This cross-sectional case–control study included 45 patients with gout and 45 age- and gender-comparable healthy controls. AGE accumulation was assessed noninvasively using skin autofluorescence (AGE-SAF). Demographic, clinical, inflammatory, metabolic, and renal variables were recorded. Correlation analyses, subgroup comparisons, receiver operating characteristic (ROC) analysis, false discovery rate (FDR)-corrected analyses, and multivariable linear regression models were performed. Results: Patients with gout had significantly higher AGE-SAF levels than healthy controls (2.46±0.69 vs. 1.83±0.24 AU, p<0.001). AGE-SAF correlated positively with age, annual attack frequency, serum creatinine, and C-reactive protein levels, and inversely with estimated glomerular filtration rate (eGFR), albumin, and the CALLY index. After FDR correction, these associations remained significant. In multivariable analyses, higher CRP levels and lower eGFR independently predicted higher AGE-SAF values. Patients with impaired renal function and hypertension exhibited significantly higher AGE-SAF levels. In an exploratory ROC analysis, AGE-SAF showed discrimination between patients with gout and healthy controls (AUC 0.846, 95% CI 0.765-0.927). Conclusion: Patients with gout exhibited increased cumulative AGE accumulation measured by skin autofluorescence. The associations of AGE-SAF with inflammatory burden, renal dysfunction, and lower CALLY index values suggest that AGE-SAF may serve as a complementary biomarker reflecting cumulative inflammatory–metabolic burden in gout. Prospective longitudinal studies are warranted to validate these findings and determine their clinical significance.