Gamma-glutamyl transferase variability can predict the development of end-stage of renal disease: a nationwide population-based study.

The aim of this study is to investigate whether GGT variability is able to predict the risk of end-stage renal disease (ESRD). The study subjects were Koreans who conducted health exams supported by the Korean National Health Insurance Corporation during 2009-2012 (baseline). After excluding individuals aged < 40 years, heavy alcoholics, or those with histories of chronic liver disease or ESRD, we followed 6,058,995 individuals. We calculated the average successive variability (ASV) of GGT values during the 5 years before the baseline as a parameter of variability. Using Cox proportional analyses, we evaluated the risk of ESRD according to GGT ASV quartiles, defined as the initiation of renal replacement therapy or kidney transplantation, or December 31, 2016. During 38,663,279.3 person-years of follow-up, 12,057 cases of ESRD were identified. Compared with GGT ASV quartile 1, the risk of ESRD was higher in ASV quartiles 3-4 and increased serially, even after adjustment for several metabolic parameters, baseline renal function, presence of comorbidities, low income, and baseline GGT and hemoglobin level. The fully adjusted hazard ratios (95% confidence intervals) of GGT ASV quartiles 3 and 4 were 1.06 (1.01-1.12) and 1.12 (1.06-1.18), respectively. In conclusion, GGT variability is a putative risk factor for ESRD in Koreans.