MP332
INDEPENDENT AND ADDITIVE PREDICTIVE EFFECTS OF SERUM GAMMA-GLUTAMYL TRANSFERASE AND ALKALINE PHOSPHATASE LEVELS ON MORTALITY IN PATIENTS WITH CHRONIC KIDNEY DISEASE Free

Introduction and Aims: High serum alkaline phosphatase (ALP) levels are associated with increased mortality in patients with chronic kidney disease (CKD). High serum gamma-glutamyl transferase (GGT) levels have also been shown to predict mortality in the general population. We hypothesized that serum GGT along with ALP may provide additional predictive information in CKD. This study aims to investigate the clinical characteristics of CKD patients with abnormally elevated serum GGT, its predictive value for mortality, and its interaction with ALP.

Methods: Retrospective observational study in a population cohort of adults with CKD stage 4-5 not yet on dialysis. Demographic, clinical, and biochemical parameters of prognostic interest were recorded and used to characterize CKD patients with high levels of GGT (>36 IU/L) and/or ALP (>120 IU/L). Cox proportional hazard regression models were used to analyze the influence of baseline serum GGT and ALP levels on time to all-cause mortality.

Results: The study group consisted of 909 patients (mean age 65±15 years, 53% males). Abnormally elevated GGT or ALP levels at baseline were observed in 209 (23%) and 172 (19%) patients, respectively, and concomitant elevations of GGT and ALP in 68 (7%). High GGT levels were associated with higher comorbidity burden, and a biochemical profile characterized by higher serum concentration of uric acid, triglycerides, alanine aminotransferase, ferritin, and C-reactive protein than those of the rest of patients. Patients with isolated elevation of ALP showed the highest mean PTH concentrations. During the study period, 365 patients (40%) died (median survival time = 74 months). In adjusted Cox regression models, high levels of GGT (hazard ratio [HR] = 1.39; 95% CI: 1.09 to 1.78, p=0.009) and ALP (HR = 1.31; 95% CI: 1.02 to 1.68, p=0.038) were independently associated with mortality. After the exclusion from the analysis of 27 patients diagnosed with liver diseases, GGT remained significantly associated with mortality (HR=1.32; 95% CI: 1.02 to 1.71; p = 0.037).

Conclusions: Abnormally elevated serum levels of GGT or ALP are independently associated with increased mortality in CKD patients, even in patients with no liver diseases.