Revising the upper limit of normal for levels of serum alanine aminotransferase in a Middle Eastern population with normal liver histology

Association of De Ritis Ratio with Prognosis in Patients with Coronary Artery Disease and Aminotransferase Activity within and outside the Healthy Values of Reference Range

BACKGROUND

The aspartate aminotransferase (AST) to alanine aminotransferase (ALT) ratio (De Ritis ratio), obtained from AST and ALT activities in the healthy range, has not been studied in association with mortality.

METHODS

This study included 3392 patients with stable coronary heart disease and aminotransferase activity in the reference range. Patients are categorized into two groups: a group with AST and ALT activity in the healthy range (n = 1697), and a group with AST and/or ALT activity outside the healthy range but in the reference range (n = 1695). The primary endpoint was all-cause mortality at three years.

RESULTS

The De Ritis ratio (median 5th-95th percentile] was 0.94 [0.61-1.41] in patients with AST and ALT in the healthy range and 0.93 [0.45-1.96] in patients with AST and/or ALT outside the healthy range (p = 0.700). At three years, there were 86 deaths in patients with AST and ALT in the healthy range: 27 deaths (3.9%) in patients with a De Ritis ratio ≤median, and 59 deaths (8.2%) in patients with the De Ritis ratio >median (adjusted hazard ratio [HR] = 1.16, 95% confidence interval [CI] 0.94 to 1.42; p = 0.159); in patients with AST and/or ALT outside the healthy range, there were 148 deaths: 49 deaths (6.6%) in patients with a De Ritis ratio ≤median, and 99 deaths (14.1%) in patients with De Ritis ratio >median (adjusted HR = 1.27 [1.09-1.48], p = 0.002), with both HRs calculated per unit higher values of the De Ritis ratio.

CONCLUSIONS

The De Ritis ratio obtained from AST and ALT activity in the healthy range was not independently associated with higher risk of mortality. The De Ritis ratio obtained from aminotransferase activity outside the healthy range (but still in the reference range) was independently associated with the risk of mortality.

Liver stiffness is associated with disease severity and worse clinical scenarios in coronavirus disease 2019: A prospective transient elastography study

BACKGROUND

Pre-existing chronic liver disease is currently considered a poor prognostic factor for coronavirus disease 2019 (COVID-19). The present study aimed to investigate the association of liver stiffness measurement (LSM) with disease severity and clinical course of COVID-19.

METHODS

We prospectively recruited consecutive hospitalised adult patients with COVID-19 in a 3-month period. Demographic, laboratory, clinical and vibration-controlled transient elastography (VCTE) features were recorded at entry, and all patients were prospectively followed-up. Severe liver fibrosis was defined as an LSM value higher than 9.6 kPA. Multivariate logistic regression analysis was performed to reveal factors associated with disease severity and outcomes.

RESULTS

Out of 98 eligible patients with COVID-19, 12 (12.2%) had severe liver fibrosis. Patients with severe liver fibrosis had higher baseline disease severity (P = .022), more commonly required oxygen treatment at entry (P = .010), and had intensive-care unit (ICU) requirements during the 6 (1-39)-day median follow-up time (P = .017). The presence of severe liver fibrosis was independently associated with disease severity (odds ratio (OR): 7.685, 95% confidence interval (CI): 1.435-41.162, P = .017) and ICU requirement (OR: 46.656, 95% CI: 2.144-1015.090, P = .014). LSM was correlated with alanine aminotransferase levels (P = .005, r: 0.283), but not with other markers of acute hepatic injury or inflammation.

CONCLUSION

Initial VCTE application might help physicians identify patients who are more likely to have severe illness or worse clinical outcomes, in addition to other well-established clinical and laboratory factors. Further multicentre prospective studies are warranted to validate our results.

Influence of Large Grafts Weighing ≥ 1000 g on Outcome of Pure Laparoscopic Donor Right Hepatectomy

BACKGROUND

Depending on a transplant center's level of experience, utilization of pure laparoscopic donor right hepatectomy (PLDRH) may be limited due to graft size or anatomical variations. Here, we aimed to evaluate the influence of large hepatic grafts (≥ 1000 g) when performing PLDRH in both donors and recipients of such grafts.

METHODS

Medical records of living donors who underwent either PLDRH from November 2015 to August 2019 or open conventional donor right hepatectomy (CDRH) from January 2010 to August 2019 and those of the graft recipients were retrospectively reviewed. Donors were separated into three groups: PLDRH graft ≥ 1000 g (n = 10; study group), PLDRH graft < 1000 g (n = 280; control-I group), and CDRH graft ≥ 1000 g (n = 24; control-II group).

RESULTS

Total operative duration (P = 0.017) and warm ischemia time (P < 0.001) were significantly longer in the study than in the control-I and control-II groups, respectively. ΔAlanine aminotransferase% was significantly lower in the study than in the control-I group (P = 0.001). There was no significant difference in minor complication incidence between the study and control-I (P = 0.068) and control-II (P = 0.618) donors. There were no major complications in the study and control-II donors, whereas six control-I donors (2.1%) experienced a major complication (P = 1.000). Length of hospitalization was significantly shorter in the study than in the control-II group (P < 0.001). There was no significant difference in early and late major complication incidence for recipients between the study and control-I and control-II groups.

CONCLUSIONS

PLDRH for grafts weighing ≥ 1000 g appears to be safe and feasible when performed by experienced surgeons in a well-equipped center.

Clinical and Metabolic Characteristics of Non-Alcoholic Fatty Liver Disease Patients in Saudi Arabia: Data from the Systematic Observatory Liver Disease (SOLID) Registry

BACKGROUND AND AIMS

The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing in Saudi Arabia (SA), but descriptions of the clinical and metabolic characteristics of these patients are limited. The present study aims to fill this gap.

METHODS

Demographic, clinical, and laboratory data of all NAFLD patients from 2009 to 2019 were retrieved from the Systematic Observatory Liver Disease Registry (SOLID) [n=832 (337 males; 495 females); mean (± standard deviation, SD) age was 42.6±13.6 years; mean body mass index (BMI) was 35.0±9.3kg/m²]. Non-invasive surrogate scores of fibrosis (eg AST to Platelet Ratio Index (APRI), Fibrosis-4 (FIB-4), and NAFLD fibrosis (NFS) scores) were calculated and analyzed. In addition, data from NAFLD patients with normal and high alanine aminotransferase (ALT) were compared using two different methods: the standard laboratory reference range which defines normal as ALT<61 IU/L, and the range proposed by a recent national study which sets upper limits of normal ALT at 33 IU/l for men and 22 IU/l for women.

RESULTS

Hyperlipidemia was the most common comorbidity (41.7%), followed by type 2 diabetes mellitus (T2DM) (35.3%) and hypertension (28.4%). Prevalence of advanced fibrosis varied widely across definitions [FIB-4, N=19 (2.5%); APRI, N=21 (2.8%); NFS, N=62 (8.6%)] and exhibited sexual dimorphism with males having worse metabolic characteristics. NAFLD patients with normal ALT were more likely to be older, female, have a lower BMI, and have a higher prevalence of cirrhosis, DM, hypertension, hyperlipidemia, and renal dysfunction.

CONCLUSION

Patients with NAFLD have metabolic characteristics associated with several comorbidities, including NAFLD patients with normal ALT. Mechanistic studies are needed to examine and analyze complex, interactive effects between sex, age, and other factors that may accelerate NAFLD disease progression.

Upper Normal Limits of Serum Alanine Aminotransferase in Healthy Population: A Systematic Review

BACKGROUND

Measuring serum alanine aminotransferase (ALT) enzyme is a routine clinical test commonly used to evaluate abnormalities in the body in general, and in the liver function in particular. Higher ALT levels are associated with some metabolic disorders. The upper limit normal (ULN) is considered as a reliable threshold for the definition of high ALT.

OBJECTIVES:

To assess the existing evidence on the ULN for ALT in the general population.

DATA SOURCE:

PubMed (Medline), EMBASE, Scopus, and Web of Science (ISI) were searched using a specified search strategy.

ELIGIBILITY CRITERIA:

We collected documents published from 1980 to 2018 in the English language, focusing on human samples at the population level and extracted the data after qualitative evaluation.

METHODS

We conducted this study in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. We used specific search terms and their combinations to find documents from relevant databases. We used a snowballing approach to find documents not captured in the main phase of the search. Two authors separately conducted the search, screened the articles, and selected documents that were qualified for data extraction based on the defined inclusion criteria. Finally, data extraction was conducted by two authors using PRISMA checklist. Reported ULNs for ALT and 95% confidence intervals (CIs) were documented in previously developed datasheets.

RESULTS

Out of 15242 studies, 47 articles were included for data extraction and analysis. Data were sparse and lacked the consistency to precisely estimate ULN for serum ALT. The ULN of ALT was significantly diverse across various geographical locations and sexes. The lowest value of ULN for ALT was 19 IU/L in Chinese children (age range: 7 to < 10 years), and the highest value of ULN for ALT was 55 IU/L in children from Ghana aged < 5 years.

LIMITATIONS:

The main limitation of the current systematic review was the scarcity of the reported measures for ULN of ALT.

CONCLUSION

Based on the results of the current systematic review, it is suggested that the normal range of ALT be redefined, but this redefinition should be done according to the localized data. In order to redefine the ULN for ALT, regional differences, methods used in ALT measurements, and ULN determination should be considered.

Endothelial dysfunction in nonalcoholic steatohepatitis with low cardiac disease risk

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide. We prospectively evaluated endothelial function by assessing flow-mediated dilatation (FMD) of the brachial artery in patients with biopsy-proven NAFLD. This prospective study included 139 patients (50 healthy controls, 47 patients with steatosis and 42 patients with steatohepatitis), all of whom were nondiabetic. Patients with long-standing or uncontrolled hypertension, smokers, and morbidly obese patients were excluded. The medians (ranges) for vascular FMD in the steatohepatitis, steatosis, and control groups were 6% (0–37.5%), 10.8% (0–40%) and 13.6% (0–50%), respectively. The control group had a higher average FMD than the NAFLD group (15.13% vs 10.46%), and statistical significance was reached when the control and steatohepatitis groups were compared (13.6% vs 6%, p = 0.027). Average alanine aminotransferase was significantly higher in the steatohepatitis group than in the steatosis and control groups (54 (U/L) vs 31 (U/L), p = 0.008). Cholesterol levels were similar between all groups. In the multivariate analysis, FMD (OR = 0.85, p = 0.035) and high triglycerides (OR = 76.4, p = 0.009) were significant predictors of steatohepatitis. In the absence of major cardiac risk factors, we demonstrated better endothelial function in healthy controls, evidenced by a higher FMD of the brachial artery than that of patients with steatohepatitis.

Redefining the Normal Values of Serum Aminotransferases in Healthy Indian Males

BACKGROUND

The normal range for Aspartate and Alanine Aminotransferases (AST and ALT) levels (<40 IU/L) were set in 1950s. Recent data from certain countries suggest lower levels of AST and ALT. Aim of the study was to redefine the normal values of aminotransferases in healthy Indian adults.

METHODOLOGY

In a cross sectional prospective study, 1002 blood donors were evaluated to isolate a healthy cohort. Four and 9 subjects positive for HBsAg and anti-Hepatitis C Virus (HCV) respectively and three females were excluded. 986 male subjects were evaluated for levels of serum aminotransferases.

RESULTS

Of total 986 subjects (Group I), 543 (55.1%) had fatty liver on ultrasound [15 (1.5%) alcoholic fatty liver and 528 (53.5%) Nonalcoholic Fatty Liver Disease (NAFLD)]. Median AST and ALT in total group (Group I) were 27.69 (Interquartile Range (IQR) 22.33-37.04) and 34.19 IU/L (IQR 23.12-54.87) and in NAFLD (Group II) were 35.67 (IQR -27.49-47.43) and 50.36 (IQR 37.70-76.58) IU/L. Of remaining 443 subjects without fatty liver, 288 had one or more components of metabolic syndrome. Out of 155 patients with no fatty liver and no component of metabolic syndrome (Group III), 103 subjects had normal Body Mass Index (BMI) and normal cholesterol and Low Density Lipoprotein (LDL) (Group III_B). Median AST and ALT in Group III_B were 22.56 (IQR 20.23-26.91) and 21.36 (IQR 17.49-27.21) U/L respectively with a 95th percentile of 34.28 and 36.57 U/L for AST and ALT, respectively.

CONCLUSION

Levels of AST and ALT in healthy men are lower than the conventional values in India.

Liver enzyme trends in patients taking uninterrupted metformin before and after coronary surgery

Background

Metformin is an oral antidiabetic agent belonging to the biguanide class of antidiabetics. Possible novel applications for metformin in cardiovascular disease might exist. The aim of this study was to verify a possible association between pre-operative metformin administration and protection against ischemia-induced liver injury in diabetic patients undergoing coronary artery bypass grafting (CABG) surgery.

Methods

A retrospective case-control series was conducted at a single center. Two hundred consecutive diabetic patients underwent isolated on-pump CABG during a 12-month span (July 2015 - July 2016). Metformin was uninterrupted in patients who took this drug prior to CABG; 68 patients were metformin users (34%) while 132 patients were taking other antidiabetic agents (66%). Liver enzymes and other organ markers were consecutively recorded daily for 7 days after surgery and expressed as medians with interquartile range (IQR).

Results

Both the metformin and non-metformin group of patients had similar pre-operative demographic characteristics. The median (IQR) post-operative cardiac enzyme creatinine kinase (CK) MB fraction was significantly lower in the metformin group [46.4 U/L (35.8-66.5) vs. 66.5 U/L (44-94.5), P=0.005]. Total bilirubin [0.58 (0.48-0.82) mg/dL vs. 0.67 (0.56-0.95) mg/dL, P=0.021], the transaminase aspartate aminotransferase (AST) [32.5 U/L (25.0-42.0) vs. 37.5 U/L (28.5-56), P=0.011], the transaminases alanine aminotransferase (ALT) [48.5 U/L (40.0-64.0) vs. 57.0 U/L (44.0-77.0), P=0.040] and lactate dehydrogenase (LDH) [320.0 U/L (273.5-367.2) vs. 356.5 U/L (289.5-427), P=0.014] were significantly lower in the metformin group. No differences were noted in clinical outcomes.

Conclusions

In this limited retrospective study, the diabetic patients who took metformin before and after undergoing CABG appeared to have a reduced post-operative surge in the total bilirubin and transaminase liver enzymes. Metformin's role in mitigating oxidative stress in liver cells might explain this observation. Further experimental studies are warranted to verify this possible effect.

Association of serum transaminases with short- and long-term outcomes in patients with ST-elevation myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

Alanine transaminase (ALT) and aspartate aminotransferase (AST) are referred to as liver transaminases. Although used routinely in clinical practice for decades, their role as predictors of mortality has not been examined until recently. We studied the predictive value of these serum transaminases in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

METHODS

We analyzed records of 2417 consecutive STEMI patients with no preexisting liver disease who were treated with primary PCI at the Cardiovascular Center in the First Hospital of Jilin University. The outcomes measured were all-cause mortality at the first month and at 2 years. The relationship between the baseline serum transaminase levels and primary outcome was determined.

RESULTS

We found a significant correlation between elevated liver transaminases and the Killip classification (P < 0.001 for ALT; P < 0.001 for AST), cardiac troponin I (P = 0.002 for ALT; P < 0.001 for AST), infarct-related coronary artery (P = 0.036 for ALT; P = 0.011 for AST), and pre-thrombolysis-in-myocardial-infarction (pre-TIMI) flow (P < 0.001 for ALT and AST). The serum level of ALT and AST were high along with the increasing of the grade of Killip classification. The primary infarct-related coronary artery in patients with ALT ≥95th percentage was left anterior descending artery (56%), followed by right coronary artery (36%). The OR for all-cause mortality at 2 years for participants with ALT ≥95th percentage was 5.370 (95% CI: 2.899-9.948), 7.034 (95% CI: 3.718-13.307) after adjustment for age and gender and 1.051 (95% CI: 0.302-3.652) after adjustment for all covariables. The OR for all-cause mortality at 2 years for participants with AST ≥95th percentage was 5.370 (95% CI 2.899-9.948) and 5.699 (95% CI 3.030-10.718) after adjustment for age and gender and 1.796 (95% CI: 0.588-5.481) after adjustment for all covariables. ALT (HR 1.004, 95% CI 1.001-1.006, P = 0.010) and AST (HR 0.999, 95% CI 0.998-1.000, P = 0.030) were associated with early all-cause mortality in patients with STEMI treated with PCI but not at 2 years post-procedure, unless for AST and ALT levels ≥95th percentage. Moreover, short- and long-term outcomes were significantly worse when both AST and ALT levels ≥95th percentage (P < 0.001).

CONCLUSIONS

Serum transaminases ≥95th percentage were associated with a significantly increased incidence of short- and long-term all-cause mortality.

TRIAL REGISTRATION

Registration number: ChiCTR-EPC-16008199 , 31 March 2016.

Transplantation of Deceased Donor Livers With Elevated Levels of Serum Transaminases at Shiraz Transplant Center

BACKGROUND

The current organ shortage has prompted the use of marginal organs. We conducted this retrospective study to present our experience with transplanting deceased donor livers with elevated levels of serum transaminases and to explain whether elevated levels of serum transaminases in donors affect allograft function and survival of the recipients.

METHODS

Data of deceased donor livers and patients, who underwent liver transplantation from March 2013 to March 2015 at Shiraz center for organ transplantation, was reviewed. Liver donors with aspartate aminotransferase (AST) and/or alanine aminotransferase (ALT) level of more than 500 IU/l and their related recipients were considered as the case group (n = 24) and the others were considered as the control group (n = 834).

RESULTS

In the case group, the medians of levels of serum AST and ALT of donors were 834 ± 425 IU/L (range: 250 - 2285) and 507 ± 367 IU/L (range: 100 - 1600), respectively. Recipients were followed for a median of 13.6 ± 9 months (range: 7 - 28.4). Post-transplant complications were acute rejection (n = 5), infection (n = 3), portal vein thrombosis (n = 3), bile duct stricture (n = 1), and hepatic artery stenosis (n = 1). The one-year survival rate of the patients was 91.7%. Demographics, post-transplant complications and one-year survival rates were not significantly different between the two study groups.

CONCLUSIONS

Transplanting deceased donor livers with markedly elevated liver enzymes may be an acceptable choice for expanding the donor pool.

Normal liver enzymes are correlated with severity of metabolic syndrome in a large population based cohort

Key features of the metabolic syndrome are insulin resistance and diabetes. The liver as central metabolic organ is not only affected by the metabolic syndrome as non-alcoholic fatty liver disease (NAFLD), but may contribute to insulin resistance and metabolic alterations. We aimed to identify potential associations between liver injury markers and diabetes in the population-based Heinz Nixdorf RECALL Study. Demographic and laboratory data were analyzed in participants (n = 4814, age 45 to 75y). ALT and AST values were significantly higher in males than in females. Mean BMI was 27.9 kg/m² and type-2-diabetes (known and unkown) was present in 656 participants (13.7%). Adiponectin and vitamin D both correlated inversely with BMI. ALT, AST, and GGT correlated with BMI, CRP and HbA1c and inversely correlated with adiponectin levels. Logistic regression models using HbA1c and adiponectin or HbA1c and BMI were able to predict diabetes with high accuracy. Transaminase levels within normal ranges were closely associated with the BMI and diabetes risk. Transaminase levels and adiponectin were inversely associated. Re-assessment of current normal range limits should be considered, to provide a more exact indicator for chronic metabolic liver injury, in particular to reflect the situation in diabetic or obese individuals.

Estimation of normal values of serum transaminases based on liver histology in healthy Asian Indians

BACKGROUND AND AIM

Liver biopsy-based studies have shown that serum levels of aminotransferases are lower than conventional cut-off of 40 IU/mL in persons with normal histology. There is no such study in Indian population based on liver histology. This study aims to estimate normal values of serum aminotransferases in healthy Indian population with normal liver histology.

METHODS

This retrospective study includes all liver donors who underwent liver donation at our centre and had a preoperative liver biopsy done for various reasons. All the donors had negative viral markers. Nonalcoholic fatty liver (NAFL) was defined as > 5% hepatocytes having steatosis and no changes of steatohepatitis.

RESULTS

The study included 331 donors (147 males) with the ages of 35.7 ± 10.2 years. NAFL was present in 167 donors (50.4%). In comparison with male donors with normal histology (n = 67), donors with NAFL (n = 80) had significantly higher age, body mass index, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase, gamma-glutamyl transpeptidase, total cholesterol, low-density lipoprotein, and fasting blood sugar. In comparison with female donors with normal histology, donors with NAFL had significantly higher body mass index, ALT, and triglycerides; however, there was no significant difference regarding other parameters. Of the AST and ALT in normal histology donors, 95th percentile were 33.8 IU/L and 38.6 IU/L for males and 31 IU/L and 35.2 IU/L for females. Twenty-five donors had lean NAFL (body mass index < 23 kg/m2).

CONCLUSION

Serum aminotransferase values in healthy Asian Indian population with normal histology are provided. Histological NAFL is present in half of apparently normal donors, and it has different clinical and biochemical associations in males and females.

Liver enzymes and risk of all-cause mortality in general populations: a systematic review and meta-analysis

BACKGROUND

Gamma glutamyltransferase (GGT), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP), commonly used as markers of liver dysfunction, have been implicated with risk of all-cause mortality. The prospective evidence on the associations in general populations has not been reliably quantified.

METHODS

We conducted a systematic review and meta-analysis of published prospective cohort studies evaluating the associations of baseline levels of these enzymes with all-cause mortality in general populations. Relevant studies were identified in a literature search of MEDLINE, EMBASE and Web of Science up to March 2013. Authors of unpublished studies provided data on request.

RESULTS

Nineteen unique cohort studies with aggregate data on over 9.24 million participants and 242 953 all-cause mortality outcomes were included. In a comparison of extreme thirds of baseline GGT and ALP levels, relative risks (RRs) (95% confidence intervals) for all-cause mortality were 1.60 (1.42-1.80) and 1.38 (1.17-1.63), respectively. The corresponding RRs for ALT were 0.82 (0.78-0.86) and 1.43 (1.08-1.90) in North American and Asian populations, respectively. There was no strong evidence of an association of AST with all-cause mortality: RR 1.23 (0.80-1.88). The pooled RRs per 5 U/l increment in GGT and ALP levels were 1.07 (1.04-1.10) and 1.03 (1.01-1.06), respectively.

CONCLUSIONS

Available data indicate positive independent associations of baseline levels of GGT and ALP with all-cause mortality, consistent with linear dose-response relationships. There were geographical variations in the association of ALT with all-cause mortality which require further investigation. The potential incremental prognostic values of GGT and ALP in mortality risk assessment need evaluation.

Alanine aminotransferase and risk of the metabolic syndrome: a linear dose-response relationship

BACKGROUND

Elevated baseline circulating alanine aminotransferase (ALT) level has been demonstrated to be associated with an increased risk of the metabolic syndrome (MetS), but the nature of the dose-response relationship is uncertain.

METHODS

We performed a systematic review and meta-analysis of published prospective cohort studies to characterize in detail the nature of the dose-response relationship between baseline ALT level and risk of incident MetS in the general population. Relevant studies were identified in a literature search of MEDLINE, EMBASE, and Web of Science up to December 2013. Prospective studies in which investigators reported relative risks (RRs) of MetS for 3 or more categories of ALT levels were eligible. A potential nonlinear relationship between ALT levels and MetS was examined using restricted cubic splines.

RESULTS

Of the 489 studies reviewed, relevant data were available on 29,815 non-overlapping participants comprising 2,125 incident MetS events from five prospective cohort studies. There was evidence of a linear association (P for nonlinearity=0.38) between ALT level and risk of MetS, characterised by a graded increase in MetS risk at ALT levels 6-40 U/L. The risk of MetS increased by 14% for every 5 U/L increment in circulating ALT level (95% CI: 12-17%). Evidence was lacking of heterogeneity and publication bias among the contributing studies.

CONCLUSIONS

Baseline ALT level is associated with risk of the MetS in a linear dose-response manner. Studies are needed to determine whether the association represents a causal relationship.

Complex association between alanine aminotransferase activity and mortality in general population: a systematic review and meta-analysis of prospective studies

Objective

Controversy exists in using alanine aminotransferase (ALT) activity for predicting long-term survival. Therefore, this research study investigated the association between ALT activity and mortality through a systematic review and meta-analysis of previous prospective studies.

Methods

Electronic literature databases, including PubMed, Embase, and the Institute for Scientific Information (ISI), were searched for relevant prospective observational studies (published before Dec 30, 2013) on the association between baseline ALT activity and ensuing all-cause/disease-specific mortality. Information on nationality, sample size, participant characteristics, follow-up duration, comparison, outcome assessment, hazard ratios (HRs) and adjusted covariates was extracted. Pooled HRs and corresponding 95% confidence intervals (CIs) were separately calculated for categorical risk estimates (highest vs. lowest ALT categories) and continuous risk estimates (per 5 U/l of ALT increment) in subgroups separated by age (<70/≥70 years).

Results

A total of twelve prospective cohort studies, totaling 206,678 participants and 16,249 deaths, were identified and analyzed. In the younger age group, the pooled HR for mortality related to liver-disease was about 1.24 (95% CI: 1.23–1.25) per 5 U/l of ALT increment. The dose-response HRs of all-cause mortality, cardiovascular (CV) disease-related mortality, and cancer-related mortality were 0.91 (0.88–0.94), 0.91 (0.85–0.96), 0.92 (0.86–0.98) respectively per 5 U/l of ALT elevation, with insignificant heterogeneity in the older population. There was an approximate decrease of 4‰ observed on HRs of all-cause, CV-related, and cancer-related mortality followed with one year's increment through meta-regression (all P<0.05).

Conclusions

The ALT-mortality association was inconsistent and seems particularly susceptible to age after synthesizing the previous prospective studies. In terms of the age, ALT activity was more valuable in predicting mortality in the older population; extremely low ALT levels indicated a higher all-cause, CV-related, and cancer-related mortality. ALT activity may therefore be a useful biomarker when predicting the long-term survival of elderly patients.

Alanine aminotransferase-old biomarker and new concept: a review

Measurement of serum alanine aminotransferase (ALT) is a common, readily available, and inexpensive laboratory assay in clinical practice. ALT activity is not only measured to detect liver disease, but also to monitor overall health. ALT activity is influenced by various factors, including viral hepatitis, alcohol consumption, and medication. Recently, the impact of metabolic abnormalities on ALT variation has raised concern due to the worldwide obesity epidemic. The normal ranges for ALT have been updated and validated considering the metabolic covariates in the various ethnic districts. The interaction between metabolic and demographic factors on ALT variation has also been discussed in previous studies. In addition, an extremely low ALT value might reflect the process of aging, and frailty in older adults has been raised as another clinically significant feature of this enzyme, to be followed with additional epidemiologic investigation. Timely updated, comprehensive, and systematic introduction of ALT activity is necessary to aid clinicians make better use of this enzyme.