Serum gamma - glutamyltransferase is associated with albuminuria: a population-based study

Development of interpretable machine learning models for prediction of acute kidney injury after noncardiac surgery: a retrospective cohort study

BACKGROUND

Early identification of patients at high-risk of postoperative acute kidney injury (AKI) can facilitate the development of preventive approaches. This study aimed to develop prediction models for postoperative AKI in noncardiac surgery using machine learning algorithms. The authors also evaluated the predictive performance of models that included only preoperative variables or only important predictors.

MATERIALS AND METHODS

Adult patients undergoing noncardiac surgery were retrospectively included in the study (76 457 patients in the discovery cohort and 11 910 patients in the validation cohort). AKI was determined using the KDIGO criteria. The prediction model was developed using 87 variables (56 preoperative variables and 31 intraoperative variables). A variety of machine learning algorithms were employed to develop the model, including logistic regression, random forest, extreme gradient boosting, and gradient boosting decision trees. The performance of different models was compared using the area under the receiver operating characteristic curve (AUROC). Shapley Additive Explanations (SHAP) analysis was employed for model interpretation.

RESULTS

The patients in the discovery cohort had a median age of 52 years (IQR: 42-61 years), and 1179 patients (1.5%) developed AKI after surgery. The gradient boosting decision trees algorithm showed the best predictive performance using all available variables, or only preoperative variables. The AUROCs were 0.849 (95% CI: 0.835-0.863) and 0.828 (95% CI: 0.813-0.843), respectively. The SHAP analysis showed that age, surgical duration, preoperative serum creatinine, and gamma-glutamyltransferase, as well as American Society of Anesthesiologists physical status III were the most important five features. When gradually reducing the features, the AUROCs decreased from 0.852 (including the top 40 features) to 0.839 (including the top 10 features). In the validation cohort, the authors observed a similar pattern regarding the models' predictive performance.

CONCLUSIONS

The machine learning models the authors developed had satisfactory predictive performance for identifying high-risk postoperative AKI patients. Furthermore, the authors found that model performance was only slightly affected when only preoperative variables or only the most important predictive features were included.

Evaluation of Homocysteine and Gamma-Glutamyl Transferase Concentrations As Markers of Chronic Kidney Disease: An Indian Perspective

Background

Chronic kidney disease (CKD) involves a gradual loss of kidney function over months to years. Oxidative stress plays a critical role in the pathogenesis of CKD. Homocysteine (Hcy), an amino acid derivative, is a known risk factor for oxidative stress and endothelial damage. Gamma-glutamyl transferase (GGT), an enzyme abundant on the cell surface of liver and kidney cells, is raised during oxidative stress. The objectives of this study were to estimate the concentrations of serum Hcy and GGT among CKD patients and healthy controls and to determine whether there is an association between serum Hcy and GGT levels in CKD.

Methodology

A total of 246 participants were needed to meet the calculated sample size. A total of 123 CKD patients meeting the inclusion and exclusion criteria were recruited as cases from the Nephrology outpatient department of our institute. Equal numbers of age- and sex-matched healthy volunteers were recruited as controls. Biophysical profiling of participants was done. Baseline investigations were recorded. A blood sample was collected from each participant and analyzed for GGT and Hcy along with other routine parameters.

Results

Hcy and GGT concentrations were significantly high in CKD patients compared to healthy controls. There was a significant positive correlation between serum GGT and Hcy levels (r = 0.357).

Conclusions

Elevated levels of GGT and Hcy in CKD patients compared to healthy controls demonstrated the oxidative stress associated with the disease. GGT and Hcy can be used as prognostic markers of the disease.

Number of parity is associated with low-grade albuminuria in middle-aged and elderly Chinese women

Background

Women with a higher number of pregnancies have a higher risk of developing cardiovascular diseases. Subtle fluctuations in albumin excretion could be related to pathophysiologic changes in the vascular system. We aimed to investigate the possible association of parity with low-grade albuminuria.

Methods

We conducted a community-based study in 6495 women aged 40 years or older. Low-grade albuminuria was defined according to the highest quartile of urine albumin-to-creatinine ratio in participants free of micro- or macro-albuminuria.

Results

Parous women with a higher number of pregnancies had increased age, body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), fasting plasma glucose (FPG), and fasting insulin, as well as decreased high-density lipoprotein cholesterol (HDL-C), estimated glomerular filtration rate (eGFR) levels, and proportion of menopause. The prevalence of low-grade albuminuria in parous women gradually increased with parity number. Compared with women with one childbirth, those with more than two childbirths were independently associated with a higher prevalent low-grade albuminuria (odds ratios [ORs] 1.41, 95% confidence interval [CI], 1.09–1.81) after multiple adjustments. In subgroup analysis after multiple adjustments, significant relation between parity number and prevalent low-grade albuminuria was detected in subjects age 55 years or older.

Conclusion

Number of parity is associated with prevalent low-grade albuminuria in middle-aged and elderly Chinese women without micro- or macro-albuminuria.

Association between serum gamma-glutamyl transferase and serum uric acid levels in Chinese females: A cross-sectional study

OBJECTIVE

To investigate the association between serum gamma-glutamyl transferase (GGT) levels and serum uric acid levels in middle-aged and elderly Chinese females.

METHODS

A cross-sectional population survey was performed in Luzhou, China (2014). Questionnaires, physical examinations and biochemical tests were conducted. Finally, we included 2486 females who were > 40 years old as participants. Multiple linear regression analysis was used to estimate the association of serum acid levels and other variables. Serum GGT levels were divided into four groups using the 25th, 50th and 75th percentiles as cut-off points. Finally, binary logistic regression analysis was used to investigate the association of different serum GGT quartiles with the risk of hyperuricemia.

RESULTS

The prevalence of hyperuricemia was 25.1% in the studied population and gradually increased across the serum GGT quartiles (P < 0.05). Binary logistic regression analysis showed that compared with subjects in the lowest quartile of serum GGT levels, the adjusted odds ratio (ORs) for uric acid in the highest quartile was 2.34 (95% confidence interval (CI), 1.68-3.28, P < 0.001),after corrections for TG, TC, HDL-C, LDL-C, creatinine (CR), GGT, AST, ALT, fasting plasma glucose (FPG), postprandial 2-h plasma glucose, hemoglobin A1c(HbA1c), age, BMI, SBP, DBP, waist-to-hip ratio and neck circumference (NC).

CONCLUSIONS

The serum GGT level is associated with hyperuricemia in middle-aged and elderly Chinese females.

A new plasma biomarker enhance the clinical prediction of postoperative acute kidney injury in patients with hepatocellular carcinoma

BACKGROUND

The ratio of serum γ-glutamyl transferase (GGT) to alanine aminotransferase (ALT) (GGT/ALT) is a marker for evaluating effects to antivirotic treatment and a helpful predictive factor for the prognosis of Child-Pugh A hepatocellular carcinoma (HCC) patients after surgery. The relationship between the incidence of postoperative acute kidney injury (AKI) and preoperative GGT/ALT is studied in hepatectomized hepatitis B- or C- associated HCC patients.

METHODS

A total of 253 hepatitis B or C virus-related HCC patients undergoing hepatectomy between September 2012 and August 2016 at our hospital were included in the retrospective study. Serum ALT and GGT value were recorded, and the GGT/ALT was computed. AKI was defined that based on the "Kidney Disease Improving Global Outcomes (KDIGO) criteria".

RESULTS

AKI was observed in 22 (8.7%) patients. Mean GGT/ALT of patients with AKI was significantly higher than in those without it (6.0 vs 2.1, P<0.001). Multivariate analysis revealed an increase in GGT/ALT as an independent risk factor for AKI in hepatitis B- or C- associated HCC patients, particularly in patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A staged HCC (odds ratio (OR) 1.400, P<0.001). Multivariate analysis showed that ALT (OR 0.966, P=0.044) was somewhat inversely associated with the incidence of AKI in hepatitis B- or C- associated HCC patients. The best cutoff point of GGT/ALT was 2.92. Multivariate analysis showed that preoperative GGT/ALT ≥2.92 predicted poor prognosis of postoperative AKI in patients with HCC after hepatectomy (odds ratio 17.697, P<0.001). After propensity score matching, preoperative GGT/ALT ≥2.92 remained an independent risk factor for AKI in HCC patients (OR 13.947, P=0.003).

CONCLUSIONS

The GGT/ALT of patients with AKI was significantly higher than those without it. Evaluation of GGT/ALT before surgery can be a helpful predictive tool for postoperative AKI in hepatitis B- or C- associated HCC patients undergoing hepatectomy, particularly in patients with BCLC stage 0 or A staged HCC. Hepatitis B- or C- associated HCC patients with low ALT especially within the normal range may have a high risk of AKI. However, the reason remains to be elucidated.

Gamma-glutamyltransferase and risk of chronic kidney disease: A prospective cohort study

BACKGROUND

Elevated serum gamma-glutamyltransferase (GGT) activity has been linked with an increased risk of chronic kidney disease (CKD) in Asian populations. We aimed to assess the prospective association of serum GGT with risk of CKD in a Caucasian population.

MATERIALS AND METHODS

We related GGT activity to the incidence of CKD in 2338 men aged 42-61years of the Kuopio Ischemic Heart Disease study with normal kidney function at baseline. Repeat measurements of GGT were used to correct for within-person variability.

RESULTS

During a median follow-up of 25.6years, 221 men developed new-onset CKD. The age-adjusted regression dilution ratio of log_e GGT was 0.70 (95% CI: 0.64-0.75). Gamma-glutamyltransferase was log-linearly associated with risk of CKD in age-adjusted analysis. In Cox regression analysis adjusted for age, the hazard ratio (95% CIs) for CKD per standard deviation increase in log_e baseline GGT was 1.25 (1.09-1.43) which was attenuated to 1.01 (0.86-1.19) on further adjustment for several confounders.

CONCLUSION

Contrary to previous evidence of an independent association between elevated GGT and increased risk of CKD in Asian populations, initial evidence of an association between GGT and CKD in Caucasian men was confounded by body mass index, lifestyle factors, and lipids.

Glycated Hemoglobin is Independently Associated with Albuminuria in Young Nondiabetic People with Obesity: A Cross-Sectional Study

Background

The aim of this study was to explore the association between glycated hemoglobin (HbA1c) level and albuminuria in young nondiabetic people with obesity.

Material/Methods

A total of 537 young nondiabetic people with obesity were enrolled in this cross-sectional study, which was approved by the Rui-jin Hospital Ethics Committee. Albuminuria was defined as a urinary albumin-to-creatinine ratio (ACR) ≥30 mg/g. Multivariate logistic regression was used to analyze the association between HbA1c level and albuminuria.

Results

Urinary ACR progressively increased across the tertiles of HbA1c level (P for trend <0.05). HbA1c levels were positively associated with the risk of albuminuria in the logistic regression analysis after adjustment for confounding factors. The adjusted odds ratio (OR) for albuminuria was 3.72 (95% confidence interval [CI], 1.25–11.00; P=0.017) when comparing between the highest (≥5.7%) and lowest tertiles of HbA1c level (≤5.3%). Moreover, an increment of 1 SD in HbA1c level increased the risk of albuminuria in a fully adjusted model (OR, 1.73; 95% CI, 1.25–2.46).

Conclusions

These data suggest that HbA1c level was independently associated with albuminuria in young nondiabetic people with obesity.

Sex difference in the association between habitual daytime napping and prevalence of diabetes: a population-based study

Our objective was to evaluate the associations between habitual daytime napping and diabetes and whether it varies by sex, menopause, and sleep quality. We conducted a population-based cross-sectional study in 8621 eligible individuals aged 40 years or older. Information on daytime napping hours, night-time sleep duration, history of menstruation, and sleep quality was self-reported. Diabetes was diagnosed according to the 1999 World Health Organization diagnostic criteria. The prevalence of diabetes was 19.4 % in men and 15.6 % in women. Increased daytime napping hours were positively associated with parameters of glycometabolism in women, such as fasting plasma glucose, oral glucose tolerance test (OGTT) 2-h plasma glucose, and Hemoglobin A1c (HbA1c, all P for trend <0.05). In women, the prevalence of diabetes in no-habitual daytime napping group, 0-1-h daytime napping group, and more than 1-h daytime napping group were 14.5, 15.6, and 20.8 %, respectively (P for trend = 0.0004). A similar trend was detected in postmenopausal women (P for trend = 0.002). In multivariate logistic regression analysis, compared with no-habitual daytime napping postmenopausal women, those with daytime napping more than 1 h had higher prevalent diabetes (odds ratios 1.36, 95 % confidence interval, 1.04-1.77). In subgroup analysis of postmenopausal women, associations of daytime napping levels and prevalent diabetes were detected in older, overweight participants with good sleep quality who have not retired from work. In conclusion, our study suggests that habitual daytime napping is associated with prevalence of diabetes in postmenopausal women.

Gamma-Glutamyltransferase: A Predictive Biomarker of Cellular Antioxidant Inadequacy and Disease Risk

Gamma-glutamyltransferase (GGT) is a well-established serum marker for alcohol-related liver disease. However, GGT's predictive utility applies well beyond liver disease: elevated GGT is linked to increased risk to a multitude of diseases and conditions, including cardiovascular disease, diabetes, metabolic syndrome (MetS), and all-cause mortality. The literature from multiple population groups worldwide consistently shows strong predictive power for GGT, even across different gender and ethnic categories. Here, we examine the relationship of GGT to other serum markers such as serum ferritin (SF) levels, and we suggest a link to exposure to environmental and endogenous toxins, resulting in oxidative and nitrosative stress. We observe a general upward trend in population levels of GGT over time, particularly in the US and Korea. Since the late 1970s, both GGT and incident MetS and its related disorders have risen in virtual lockstep. GGT is an early predictive marker for atherosclerosis, heart failure, arterial stiffness and plaque, gestational diabetes, and various liver diseases, including viral hepatitis, other infectious diseases, and several life-threatening cancers. We review literature both from the medical sciences and from life insurance industries demonstrating that serum GGT is a superior marker for future disease risk, when compared against multiple other known mortality risk factors.

Predictive Value of Gamma-Glutamyl Transferase Levels for Contrast-Induced Nephropathy in Patients With ST-Segment Elevation Myocardial Infarction Who Underwent Primary Percutaneous Coronary Intervention

Contrast-induced nephropathy (CIN) after primary percutaneous coronary intervention (PPCI) is associated with adverse short- and long-term outcomes. The aim of this study was to evaluate the predictive value of gamma-glutamyl transferase (GGT) for risk of CIN in patients with ST-segment elevation myocardial infarction who underwent PPCI. A total of 473 patients were enrolled in the study. A relative increase in serum creatinine ≥25%, or an absolute increase ≥0.5 mg/dl, from the baseline within 72 hours of contrast exposure was defined as CIN. Patients were divided into 3 groups according to GGT tertiles (tertile 1, GGT <19 U/L; tertile 2, GGT 19 to 33 U/L; and tertile 3, GGT >33 U/L) on admission. Demographics, clinical risk factors, laboratory parameters, CIN incidence, and other inhospital clinical outcomes were compared among GGT tertiles. CIN incidence was significantly higher in tertile 3 (29%) compared with tertiles 1 (11%) and 2 (11%, p <0.001). Inhospital death incidence was significantly increased across tertiles (from tertile 1 to tertiles 2 and 3, 1%, 4%, and 5%, respectively, p <0.05). In receiver operating characteristic analysis, a threshold value of GGT >26.5 U/L had 70% sensitivity and 60% specificity for CIN. After including variables found significant in univariate analysis, the presence of diabetes mellitus (odds ratio [OR] 1.71, 95% confidence interval [CI] 1.22 to 2.31, p <0.001), C-reactive protein (for each 1 mg/L increase; OR 1.01, 95% CI 1.00 to 1.02, p = 0.007), contrast volume (for each 1-ml increase; OR 1.01, 95% CI 1.00 to 1.02, p = 0.012), and GGT >26.5 U/L (OR 2.59, 95% CI 1.48 to 4.53, p <0.001) were found as independent associates of CIN in multivariate regression analysis. Each 1 U/L increase in GGT was also associated with CIN risk (OR 1.04, 95% CI 1.03 to 1.06, p <0.001). In conclusion, GGT on admission was a significant and independent predictor of CIN after PPCI in patients with ST-segment elevation myocardial infarction.