Variability in gamma-glutamyl transferase levels linked to ESRD risk

Variability in the levels of gamma-glutamyl transferase (GGT) appears to predict the development of end-stage renal disease (ESRD), reports a recent Korean study.

Researchers conducted a nation-wide, population-based study including 6,058,995 individuals. Variability in GGT was assessed using the average successive variability (ASV), standard deviation (SD), and coefficient of variation (CV) of serial GGT measurements. A diagnosis of ESRD, defined as kidney transplantation or initiating renal replacement therapy, was the primary outcome.

Over 38,663,279.3 person-years of follow-up, 12,077 of the enrolled participants developed ESRD, yielding an overall rate of 0.2 percent.

Analysis according to GGT quartile at baseline showed that ESRD was significantly more likely to occur in patients in the topmost quartile (hazard ratio [HR], 1.15, 95 percent confidence interval [CI], 1.09–1.21; p_trend<0.001). Similarly, those in the highest quartile of GGT ASV saw a significant spike in the risk of ESRD (HR, 1.12, 95 percent CI, 1.06–1.18; p_trend<0.001).

These results were largely robust to subgroup analyses. GGT ASV remained significantly indicative of ESRD risk in most models, except in patients who were of low income, who drank alcohol, and who had baseline estimated glomerular filtration rate <90 mL/min/1.73 m².

Notably, the researchers reported similar and significant links between ESRD risk and GGT variability expressed as SD or CV.

“To our knowledge, this is the first study to investigate the relationship between GGT variability and the development of ESRD in a large general population,” the researchers said. “Because the serum GGT level is already a component of liver function tests routinely used with low cost, we expect that serial GGT measurements will be a meaningful predictor of ESRD risk.”