Prognostic Value of Serum Gamma-Glutamyltransferase, Calcium, and Inorganic Phosphorus Levels in Short-Term Mortality of Patients with Acute Coronary Syndrome

Abstract

Objective: Gamma-glutamyltransferase (GGT) may be considered as a biomarker of “oxidative stress” associated with glutathione metabolism and a possible “proatherogenic” marker because of its indirect relationship with the biochemical steps in the oxidation of low density lipoprotein cholesterol. Serum inorganic phosphorus (P) level is also suggested as an independent risk factor for cardiac events and mortality in the long term. We aimed to observe the relationship of serum GGT, calcium (Ca), and P levels with 1 months’ mortality after myocardial infarction.Methods: Our retrospective study included 200 patients (124 men and 76 women) with acute coronary syndrome (ACS) who were admitted to our hospital. We excluded subjects with severe systemic illness, hepatobiliary disease, alcohol consumption, chronic metabolic bone disease, malignancy, parathyroid disease, and patients who had a glomerular filtration rate (GFR) <60 mL/min. Fasting blood samples were taken in the first 24 h of admission to the coronary care unit (CCU). Reference values for GGT (9-36 U/L, for women; 12-64 U/L, for men), Ca (8.4-10.2 mg/dL), and inorganic P (≤4.5 mg/dL) were used. When the serum albumin level was <4.0 g/dL, corrected Ca levels were calculated using the equation [corrected Ca=measured Ca+(0.8×(4-serum albumin)]. Statistical analysis was performed using SPSS for Windows 10.0. Descriptive statistical analysis, Student’s t-test, Mann-Whitney U-test, and chi-square test were used.Results: At the end of 1 month, we found significantly higher levels of blood GGT, P, and Ca×P products in patients who did not survive (n=23; 32.9 U/L, 3.66 mg/dL, 35.93 mg2/dL2) than in survivors (n=177; 24.16 U/L, 3.27 mg/dL, 31.57 mg2/dL2; p<0.001, p<0.001, p<0.001, respectively).Conclusion: Serum GGT, P, and Ca×P levels, even in the reference intervals, had a prognostic value in the short-term mortality apart from traditional risk factors such as diabetes mellitus, hypertension, and ischemic heart disease. This study also suggests constituting new reference values for this high risk population in stratifying patient risk and in assessing the intensity of appropriate treatment, with hopes of preventing cardiac deaths.

Keywords

• Acute coronary syndrome
• mortality
• Gamma-glutamyltransferase
• calcium
• phosphorus