Significance Of Serum γ-glutamyl Transpeptidase Levels Or Total Bilirubin Levels For Detection Of Target Organ Damage In Hypertension

Objective:To explore the association between serumγ-glutamyl transpeptidase levels or total bilirubin levels and asymptomatic subclinical target organ damage in hypertension.Methods:A total of 501 hypertensive patients admitted to the Department of Cardiology,Second Affiliated Hospital of Nanchang University from September 2017 to September 2018 were included in this study.Divided into 4 groups according to the quaternary point ofγ-glutamyl transpeptidase:Group A(≤17.07U/L),Group B(17.08U/L~22.99U/L),Group C(23.00U/L~35.71U/L),Group D(≥35.71U/L).Divided into another 4 groups based on the total bilirubin level quartile:Group W(≤9.70μmol/L),Group X(9.71μmol/L~11.91μmol/L),Group Y(11.92μmol/L~15.19μmol/L),Group Z(≥15.19μmol/L).Blood biochemistry and urine protein were measured,and echocardiography,carotid ultrasound,fundus photography,and brain magnetic resonance imaging were performed.Define hypertensive target organ damage according to the "Chinese Hypertension Prevention Guide 2018 Revision".The incidence of target organ damage in each group was compared,and the risk factors of target organ damage in hypertension were analyzed.Results:1.There was no significant difference in the proportion of each target organ damage assessment performed by each group.There was no significant difference in carotid artery and fundus target organ damage among the groups.Compared with group D,group A had a lower brain(64.7% vs.85.8%,P<0.001),heart(26.2% vs.45.6%,P=0.001),and renal(13.5% vs.32.0%,P<0.001) target organ damage ratio,group B had a lower heart(32.0% vs.85.8%,P=0.027),renal(12.0% vs.32.0%,P<0.001) target organ damage ratio,group C had a lower renal(18.4% vs.32.0%,P=0.013) target organ damage ratio.Linear trend tests showed a linear correlation between the number of target organ damage andγ-glutamyl transpeptidase levels(total variation:χ~2=22.522,P=0.032;linear trend test:χ~2=13.634,P<0.001).Spearman correlation analysis showed thatγ-GT levels were positively correlated with total cholesterol(r=0.260,P<0.001),low-density lipoprotein cholesterol(r=0.193,P<0.001),urinary microalbumin(r=0.158,P<0.001),septal thickness(r=0.175,P<0.001),left ventricular end diastolic diameter(r=0.135,P=0.002),left ventricular mass index(r=0.161,P<0.001),body mass index(r=0.144,P=0.001),smoking(r=0.170,P<0.001),systolic blood pressure(r=0.120,P=0.007),and diastolic blood pressure(r=0.226,P<0.001),but were negatively correlated with women(r=-0.158,P<0.001).Multivariate logistic regression showed that highγ-glutamyl transpeptidase levels(>50 U/L)increased the risk of damage to 2 or more target organs,[OR:2.876(1.298,6.373)].2.There were no significant differences in brain target organ damage,carotid target organ damage,and fundus target organ damage among the different total bilirubin levels.Compared with group Z,the proportion of target target organ damage in group X was significantly higher(42.7% vs.28.0%,P=0.015),and group W also showed a higher trend(39.4% vs.28.0%,P=0.056),despite without a statistical difference.The proportion of renal target organ damage in Group W was also significantly higher than that in Group D(28.3% vs.12.0%,P<0.001).Linear trend tests did not show a linear relationship between the number of target organ damage and bilirubin levels(total variation:χ~2=12.326,P=0.420;linear trend test:χ~2=1.575,P=0.210).Multivariate logistic regression showed that total bilirubin levels did not enter the equation.Conclusion:1.In patients with established hypertension,patients with high γ-GT levels have an increased risk of target organ damage.In clinical work,special attention should be paid to screening for target organ damage in hypertensive patients with high serum γ-GT levels.Serum γ-GT levels have certain clinical reference value for the early detection of asymptomatic subclinical target organ damage in hypertension,especially for outpatients or patients who refuse more examinations to assess target organ damage.2.Reduced bilirubin levels are associated with increased risk of heart and kidney target organ damage in hypertensive patients,suggesting that bilirubin may have a protective effect on the heart and kidneys.However,the predictive value of bilirubin levels on target organ damage of hypertension is not reliable.And the value of early detection of asymptomatic subclinical target organ damage in hypertension is limited.