Predictive value of serum albumin-to-globulin ratio for incident chronic kidney disease: A 12-year community-based prospective study

BACKGROUND: Inflammation plays a pivotal role in the pathogenesis of chronic kidney disease (CKD). Significant association between serum albumin-to-globulin (AG) ratio and inflammation led us to investigate the prognostic value of serum AG ratio for incident CKD. METHODS: The predictive value of serum AG ratio, white blood cell (WBC), and C-reactive protein (CRP) for CKD development was assessed in 8,057 non-CKD participants from a community-based, prospective cohort in Korea. Serum AG ratio was calculated by following equation: serum albumin (g/L)/[serum total protein (g/L)-serum albumin (g/L)]. Incident CKD was defined as estimated glomerular filtration rate <60 mL/min/1.73 m(2) and/or proteinuria of more than 1+ on dipstick. RESULTS: Median serum AG ratio was 1.38 (interquartile range, 1.28–1.52). During a mean follow-up duration of 9.1±3.7 years, 1,732 participants (21.5%) developed CKD. In a multivariable Cox analysis, a low serum AG ratio was significantly associated with an increased risk of incident CKD (Q1, serum AG ratio <1.26: hazard ratio [HR] = 1.651, 95% confidence interval [CI] = 1.406–1.938, Q5 as reference; per 0.2 decrease, HR = 1.170, 95% CI = 1.109–1.234). Serum AG ratio was the only indicator to improve the predictability of CKD development (net reclassification index = 0.158, P <0.001; integrated discrimination improvement = 0.005, P <0.001), compared with WBC or CRP. CONCLUSIONS: This study demonstrates that low serum AG ratio is an independent predictor for CKD development and exhibits a stronger predictive value than other inflammatory markers. These findings suggest that determining serum AG ratio may be more valuable for predicting adverse kidney outcomes in non-CKD populations.