Updated thresholds for serum alanine aminotransferase level in a large-scale population study composed of 34 346 subjects

Aminotransferase levels in clinical practice - what is normal?

PURPOSE OF REVIEW

No universal consensus exists as to what the upper limit of normal for alanine aminotransferase (ALT) should be. The purpose of this review is to provide insight on the wide variation in the upper limit of normal for ALT, and to highlight key elements resulting in these differences. We also wish to point to potential solutions for standardizing the upper limit of normal.

RECENT FINDINGS

There are considerable differences in the values for what constitutes a 'normal' ALT serum concentration set by laboratories, and reference values may vary two-fold between different institutions (from 30 to 60 U/l). Key reasons for this include using markedly different reference populations to establish the bounds of normal, and differences in analyzers and assays used to quantify ALT levels. A number of studies have attempted to re-evaluate the upper limit of normal and propose new cut-offs that would allow better detection of liver disease.

SUMMARY

The upper limit of normal for ALT continues to vary from one laboratory to another. Despite ongoing efforts, there is still an unmet demand to standardize ALT reference ranges, which is critical for clinical practice. More rigorous inclusion criteria for reference population studies and harmonization in analyzer differences is required to standardize ALT reference ranges universally.

Potential Hepatic Lipid Markers Associated with Nonalcoholic Steatohepatitis and Fibrosis in Morbid Obesity Patients

This study investigated differences in lipidomic profile features in nonalcoholic steatohepatitis (NASH) between mild and significant liver fibrosis cases among patients with morbid obesity. Wedge liver biopsy was performed during sleeve gastrectomy and significant liver fibrosis was defined as a fibrosis score ≥ 2. We selected patients with NASH with non/mild fibrosis (stage F0-F1; n = 30) and NASH with significant fibrosis (stage F2-F4; n = 30). The results of the liver tissue lipidomic analysis revealed that the fold changes of triglyceride (TG) (52:6); cholesterol ester (CE) (20:1); phosphatidylcholine (PC) (38:0) and (50:8); phosphatidic acid (PA) (40:4); phosphatidylinositol (PI) (49:4); phosphatidylglycerol (PG) (40:2); and sphingomyelin (SM) (35:0) and (37:0) were significantly lower in patients with NASH with F2-F4 than those with NASH with F0-F1 (p < 0.05). However, the fold changes of PC (42:4) were relatively higher in patients with NASH with stage 2-4 fibrosis (p < 0.05). Moreover, predictive models incorporating serum markers levels, ultrasonographic studies, and levels of specific lipid components [PC (42:4) and PG (40:2)] yielded the highest area under receiver operating curve (0.941), suggesting a potential correlation between NASH fibrosis stages and liver lipid accumulation among specific lipid species subclasses. This study demonstrated that the concentrations of particular lipid species in the liver correlate with NASH fibrosis stages and may indicate hepatic steatosis regression or progression in patients with morbid obesity.

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.

Updated upper limits of normal serum alanine aminotrasferase levels for screening metabolic dysfunction-associated fatty liver disease in obese children

BACKGROUND/PURPOSE

Alanine aminotransferase (ALT) is a cost-effective screening test for asymptomatic liver diseases. The aims of this study are to redefine the ULNs of ALT using the 2010-2012 Nutrition and Health Survey in Taiwan (NAHSIT) database and to determine whether the updated ULNs can better screen for metabolic dysfunction-associated fatty liver disease (MAFLD) in obese children.

METHODS

Reference data were obtained from 2895 NAHSIT participants (1442 boys, 1453 girls) aged 6-18 years. Participants with any of MAFLD-related metabolic risk factors, including overweight/obesity, elevated triglyceride, low high-density lipoprotein cholesterol and high fasting glucose, were excluded. This study compared the sensitivities of different ULNs of ALT for detecting MAFLD in our previously established cohort of obese children.

RESULTS

The ULNs of ALT defined as the 95th percentile in metabolically healthy NAHSIT participants were 23 IU/L for boys and 18 IU/L for girls. When using the updated ULNs, the percentages of elevated ALT levels were 13.0% in boys and 7.8% in girls of all NAHSIT participants. When using the updated ULNs of ALT to detect MAFLD in obese children, the sensitivity was 84.0% in boys and 74.3% in girls. In contrast, when using the conventional ALT cutoff (>40 IU/L), the sensitivity decreased to 61.4% in boys and 36.4% in girls.

CONCLUSION

After taking into account MAFLD-related metabolic risk factors, the ULNs of ALT are 23 IU/L for boys and 18 IU/L for girls in Taiwan. The updated ULNs may be better cutoffs for screening MAFLD in obese children.

Updated upper limit of normal for serum alanine aminotransferase value in Vietnamese population

BACKGROUND

Alanine aminotransferase (ALT) is a marker of hepatic damage and its range can be affected by viral hepatitis, alcoholic hepatitis and non-alcoholic fatty liver diseases. We aimed to study the factors associated with higher ALT level and update the upper limit of normal (ULN) in the Vietnamese population.

METHODS

This cross-sectional study enrolled 8383 adults, aged 18 years and older who visited the Medical Center at Ho Chi Minh City for a health check-up. Following the exclusion criteria, 6677 subjects were included in the analysis.

RESULTS

Age ≤40 years, male gender, body mass index >23 kg/m2, diastolic blood pressure >85 mm Hg, cholesterol >5.2 mmol/L, triglyceride >1.7 mmol/L, positivity, anti-hepatitis C virus positivity and fatty liver (p<0.05) were associated with higher ALT level (>40 U/L). Without considering age and gender, healthy group is defined after exclusion of participants with one of the mentioned contributing factors. The median ALT level in the healthy group was 18 in men and 13 in women. The ULN at the 95th percentile of the healthy group was 40 U/L in men and 28 U/L in women.

CONCLUSION

The ULN for ALT in healthy women was lower than in healthy men. Updated ULN for ALT level can promote the identification of unhealthy subjects. More studies that involve ethnicity and lifestyle factors are needed to confirm the new ULN in the Vietnamese population.

High Aspartate Aminotransferase/Alanine Aminotransferase Ratio May Be Associated with All-Cause Mortality in the Elderly: A Retrospective Cohort Study Using Artificial Intelligence and Conventional Analysis

Low serum alanine aminotransferase (ALT) activity and high aspartate aminotransferase (AST)/ALT ratio may be associated with high mortality in the elderly. We aimed to confirm this in an 8-year retrospective cohort study. Clinical data for 5958 people living in a city aged 67−104 years were analyzed for their relationships with all-cause mortality using artificial intelligence (AI) and conventional statistical analysis. In total, 1413 (23.7%) participants died during the study. Auto-AI analysis with five rounds of cross-validation showed that AST/ALT ratio was the third-largest contributor to mortality, following age and sex. Serum albumin concentration and body mass index were the fourth- and fifth-largest contributors. However, when serum ALT and AST were individually considered in the same model, the individual serum ALT and AST activities were the seventh- and tenth-largest contributors. Conventional survival analysis showed that ALT, AST, and AST/ALT ratio as continuous variables were all associated with mortality (adjusted hazard ratios (95% confidence intervals): 0.98 (0.97−0.99), 1.02 (1.02−1.03), and 1.46 (1.32−1.62), respectively; all p < 0.0001). In conclusion, both AI and conventional analysis suggest that of the conventional biochemical markers, high AST/ALT ratio is most closely associated with all-cause mortality in the elderly.

Age Dependence of Liver Enzymes: An Analysis of Over 1,300,000 Consecutive Blood Samples

BACKGROUND & AIMS

Upper levels of normal for alanine aminotransferase (ALT), aspartate aminotransferase (AST), and γ-glutamyltransferase (GGT) generally take sex into account, but not age. This simplification may lead to misclassification and burden the patient and health system unnecessarily.

METHODS

Consecutive blood samples were analyzed from a German laboratory. Subcohorts included samples from a prescribed routine check-up and a healthy cohort, defined as patients without increased GGT, triglyceride, cholesterol, glycated hemoglobin, or glucose levels, and without known hepatitis B.

RESULTS

A total of 1,369,180 blood samples were analyzed from 601,779 participants (50.8% female; mean age, 58.5 y; SD, 18.0 y). There is an extreme age dependence in ALT values for men: increased values were seen in 20.0% (95% CI, 19.5%-20.4%) of patients in the age group of 25 to 34 years, but only 6.7% (95% CI, 6.4%-7.0%) for the ages of 65 to 74 years. The 95th percentile reaches values greater than 80 U/L instead of 50 U/L at the age of 35, and decrease to less than 50 U/L by the age of 75. Similar qualitative results were found in the healthy and prescribed routine check-up subcohorts. The age dependence is much weaker for ALT in women. The proportion of women with an increased AST level increases from approximately 6% to 12% at approximately age 50. The 95th percentile for GGT increases up to the age of 60 in men, and throughout life in women.

CONCLUSIONS

Current guidelines and reference values for ALT imply that subsequent diagnostics are needed for a large proportion of young men. Our data strongly suggest that age adaptation should be considered.

Combined evaluation of aminotransferases improves risk stratification for overall and cause-specific mortality in older patients

BACKGROUND

Recent studies identified low levels of alanine aminotransferase (ALT) as strong predictors of mortality in older people.

AIMS

Here we verified if the combined evaluation of aminotransferases may improve risk stratification for adverse outcomes in older patients.

METHODS

Data are from 761 participants aged more than 65 years from a prospective population-based database (InCHIANTI study), without known baseline chronic liver disease or malignancies. Associations between aminotransferase levels and the risk of all-cause, cardiovascular- and cancer-death were assessed by Cox-models with time-dependent covariates.

RESULTS

The association of ALT and aspartate aminotransferase (AST) with mortality was non-linear, mirroring a J- and a U-shaped curve, respectively. Based on quintiles of transaminase activities and on their association with overall mortality, low, intermediate (reference group) and high levels were defined. Having at least one transaminase in the low range [aHR 1.76 (1.31-2.36), p < 0.001], mainly if both [(aHR 2.39 (1.81-3.15), p < 0.001], increased the risk of overall mortality, as well as having both enzymes in the high range [aHR 2.14 (1.46-3.15), p < 0.001]. While similar trends were confirmed with respect to cardiovascular mortality, subjects with the highest risk of cancer mortality were those with both enzymes in the high range [aHR 3.48 (1.43-8.44), p = 0.006]. Low levels of transaminases were associated with frailty, sarcopenia and disability, while high levels did not capture any known proxy of adverse outcome. Conclusions and discussion The prognostic information is maximized by the combination of the 2 liver enzymes. While both aminotransferases in low range are characteristically found in the most fragile phenotype, both enzymes in high range are more likely to identify new-onset vascular/infiltrative diseases with adverse outcome.

The liver in COVID-19: prevalence, patterns, predictors, and impact on outcomes of liver test abnormalities

BACKGROUND

Coronavirus disease 2019 (COVID-19) has caused a global pandemic unprecedented in over a century, with ≈35 million cases, and more than 1 million deaths globally. Though predominantly a lower respiratory illness, other organ injuries are well-recognized. Among these, liver injury is of major interest.

OBJECTIVE

To define prevalence, pattern, predictors, and impact of liver injury among patients hospitalized with COVID-19.

METHODS

Demographic, clinical, and biochemical data were collected retrospectively among patients admitted to St. Luke's University Hospital with COVID-19 between 1 March and 18 April 2020. Association of liver tests (LTs) with mortality and need for mechanical ventilation, adjusted for demographic, clinical and biochemical predictors, was examined.

RESULTS

Data were available on 551 patients. Prevalence of any or ≥3 × upper limit of normal transaminase elevation on was 61.2 and 9.4% on admission, and 72.1 and 22.4% at peak. Bilirubin and alkaline phosphatase elevations were less common on admission (11.4 and 12.6%, respectively), and at peak (17.7 and 22%, respectively). All liver test (LT) elevations were consistently predicted by inflammatory markers. Hyperbilirubinemia predicted mortality on admission and at peak. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) had opposite impact on mortality with AST positively, and ALT negatively associated with mortality. Hence, besides hyperbilirubinemia, AST:ALT ratio emerged as the best marker for mortality among the LTs.

CONCLUSION

LT elevations among patients presenting with COVID-19 are very common, though majority are mild. Admission and peak bilirubin ≥1 mg/dl, as well as admission and peak AST:ALT ratio were significant predictors of mortality, along with age, myocardial injury, and chronic medical illness.

Transaminase Concentrations Cannot Separate Non-Alcoholic Fatty Liver and Non-Alcoholic Steatohepatitis in Morbidly Obese Patients Irrespective of Histological Algorithm

BACKGROUND

In current general practice, elevated serum concentrations of liver enzymes are still regarded as an indicator of non-alcoholic fatty liver disease (NAFLD) or non-alcoholic steatohepatitis (NASH). In this study, we analyzed if an adjustment of the upper limit of normal (ULN) for serum liver enzymes can improve their diagnostic accuracy.

METHODS

Data from 363 morbidly obese patients (42.5 ± 10.3 years old; mean BMI: 52 ± 8.5 kg/m2), who underwent bariatric surgery, was retrospectively analyzed. NAFL and NASH were defined histologically according to non-alcoholic fatty liver activity score (NAS) and according to steatosis activity fibrosis (SAF) score for 2 separate analyses, respectively.

RESULTS

In 121 women (45%) and 45 men (46%), elevated values for at least one serum parameter (ALT, AST, γGT) were present. The serum concentrations of ALT (p < 0.0001), AST (p < 0.0001) and γGT (p = 0.0023) differed significantly between NAFL and NASH, irrespective of the applied histological classification method. Concentrations of all 3 serum parameters correlated significantly positively with the NAS and the SAF score, with correlation coefficients between 0.33 (ALT/NAS) and 0.40 (γGT/SAF). The area under the curves to separate NAFL and NASH by liver enzymes achieved a maximum of 0.70 (ALT applied to NAS-based classification). For 95% specificity, the ULN for ALT would be 47.5 U/L; for 95% sensitivity, the ULN for ALT would be 17.5 U/L, resulting in 62% uncategorized patients.

CONCLUSION

ALT, AST, and γGT are unsuitable for non-invasive screening or diagnosis of NAFL or NASH. Utilizing liver enzymes as an indicator for NAFLD or NASH should generally be questioned.

Fibroscan-Based Score to Predict Significant Liver Fibrosis in Morbidly Obese Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND

The prevalence rate of nonalcoholic fatty liver disease (NAFLD) has been reported in 74 to 90% of morbidly obese patients. This study aims to develop a scoring system that predicts significant liver fibrosis in morbidly obese patients.

METHODS

This prospective cohort study involved 123 morbidly obese patients who underwent metabolic surgery at Taipei Medical University Hospital between October 2016 and June 2018. Wedge liver biopsy was performed during surgery, and significant liver fibrosis was defined as a fibrosis score ≧ 2. Ultrasonography and transient elastography were performed prior to surgery to assess the risk factors associated with significant liver fibrosis.

RESULTS

Mean patient age was 35.5 years, mean body mass index (BMI) was 40.6 kg/m2, and 87 (70.7%) were female. Fibrosis staging revealed 28 (22.8%) at stage 2, 14 (11.4%) at stage 3, and 2 (1.6%) at stage 4. Patients were then separated into training (n = 73) and validation (n = 50) cohorts. Multivariate analysis revealed a liver stiffness measurement (LSM) > 7 kPa and aspartate aminotransferase/platelet ratio index (APRI) > 0.40 as independent factors associated with significant liver fibrosis among the training cohort. Fibroscan-base score weighted sum of (1 for presence of APRI > 0.40) + (2 for presence of LSM > 7 kPa) yielded the highest area under receiver operating curve (0.854, P = 0.0001; 0.785, P = 0.0002) compared with other non-invasive markers in the training and validation cohorts, respectively.

CONCLUSION

We developed a simple, clinical scoring system incorporating Fibroscan and APRI to predict significant liver fibrosis in morbidly obese patients.

Interleukin-2 receptor alpha as a biomarker for nonalcoholic fatty liver disease diagnosis

BACKGROUND

Two recent studies in the adult and pediatric Nonalcoholic Steatohepatitis-Clinical Research Network (NASH-CRN) cohorts have shown that soluble interleukin-2 receptor alpha (IL2RA) levels increased with fibrosis severity. However, no hepatic study has been conducted in Asian morbidly obese patients who underwent bariatric surgery. In this study, we proposed IL2RA as a biomarker for nonalcoholic fatty liver disease (NAFLD) diagnosis and performed immunohistochemistry (IHC) staining of IL2RA.

METHODS

This prospective cohort study enrolled 123 morbidly obese patients who underwent bariatric surgery at Taipei Medical University Hospital from October 2016 to June 2018. During bariatric surgery, all patients underwent a wedge liver biopsy under laparoscopic guidance. The diagnoses of NASH and liver fibrosis were made histologically. In IHC of IL2RA, the number of lymphocytes with IL2RA immunoreactivity was counted in five high-power fields (×400, total: 1.19 mm2).

RESULTS

Among the 123 patients, the mean age was 35.5 years, mean body mass index (BMI) was 40.6 kg/m2, 87 (70.7%) were female, 25 (20.7%) had diabetes mellitus, and 57 (46.3%; 11 with non-NAFLD and 46 with steatosis) and 66 (53.7%) were included in the non-NASH and NASH groups, respectively. The NASH group had higher IHC of IL2RA than the non-NASH group. In multivariate analysis, IHC of IL2RA (odds ratio, 1.025; 95% confidence interval, 1.006-1.045; p = 0.011) and alanine aminotransferase (ALT; odds ratio, 1.045; 95% confidence interval, 1.018-1.073; p = 0.001) were the independent factors associated with NASH. The area under the receiver operating curve of IL2RA IHC for NASH was 0.627 at the cutoff value of 82 (p = 0.0113).

CONCLUSION

IL2RA is significantly associated with NASH in morbidly obese patients and would be a useful biomarker for NASH diagnosis.

A male-ABCD algorithm for hepatocellular carcinoma risk prediction in HBsAg carriers

Objective

Hepatocellular carcinoma (HCC) development among hepatitis B surface antigen (HBsAg) carriers shows gender disparity, influenced by underlying liver diseases that display variations in laboratory tests. We aimed to construct a risk-stratified HCC prediction model for HBsAg-positive male adults.

Methods

HBsAg-positive males of 35−69 years old (N=6,153) were included from a multi-center population-based liver cancer screening study. Randomly, three centers were set as training, the other three centers as validation. Within 2 years since initiation, we administrated at least two rounds of HCC screening using B-ultrasonography and α-fetoprotein (AFP). We used logistic regression models to determine potential risk factors, built and examined the operating characteristics of a point-based algorithm for HCC risk prediction.

Results

With 2 years of follow-up, 302 HCC cases were diagnosed. A male-ABCD algorithm was constructed including participant’s age, blood levels of GGT (γ-glutamyl-transpeptidase), counts of platelets, white cells, concentration of DCP (des-γ-carboxy-prothrombin) and AFP, with scores ranging from 0 to 18.3. The area under receiver operating characteristic was 0.91 (0.90−0.93), larger than existing models. At 1.5 points of risk score, 26.10% of the participants in training cohort and 14.94% in validation cohort were recognized at low risk, with sensitivity of identifying HCC remained 100%. At 2.5 points, 46.51% of the participants in training cohort and 33.68% in validation cohort were recognized at low risk with 99.06% and 97.78% of sensitivity, respectively. At 4.5 points, only 20.86% of participants in training cohort and 23.73% in validation cohort were recognized at high risk, with positive prediction value of 22.85% and 12.35%, respectively.

Conclusions

Male-ABCD algorithm identified individual’s risk for HCC occurrence within short term for their HCC precision surveillance.

African Americans Demonstrate Significantly Lower Serum Alanine Aminotransferase Compared to Non-African Americans

BACKGROUND AND AIMS

Normal ranges of serum alanine aminotransferase (ALT) may vary by race. However, results from research studies are contradictory, and many of these studies have included only small numbers of African Americans. We investigated ALT values in patients without evidence of liver disease to determine whether normal ranges differ across race groups. We also evaluated whether a race- and sex-dependent upper limit of normal (ULN) would improve the ability of ALT to predict liver disease compared to the sex-dependent ULN currently in use.

METHODS

We identified ICD9 codes for liver conditions and diabetes in medical records from a sample of 6719 patients. Analysis of variance (ANOVA) was used to assess differences in ALT log-transformed distributions by race. Logistic regression was used to evaluate whether the addition of race to the current sex-dependent ULN improves the ability of ALT to predict liver disease (assessed by area under the receiver operating characteristic curve (AUROC)).

RESULTS

Among 1200 patients with BMI 18.5 < 25 and no evidence of liver disease or type 2 diabetes in their medical record, African Americans demonstrated significantly lower ALT (23.47 IU/L; 95% CL 22.87-24.10) than a combined group of Asian American/White/Other patients (25.71 IU/L; 95% CL 24.69-26.77). This difference remained across BMI categories. The race- and sex-dependent model demonstrated significantly better predictive ability than the sex-dependent model (AUROC = 66.6% versus 59.6%, respectively; p < 0.0001).

CONCLUSIONS

In a large, racially diverse sample, African Americans demonstrated significantly lower ALT compared to non-African Americans; this difference remained as BMI increased. The establishment of race-specific normal ranges for ALT could contribute to better screening and care for African American patients.

ALT Levels for Asians With Metabolic Diseases: A Meta-analysis of 86 Studies With Individual Patient Data Validation

The current alanine aminotransferase (ALT) upper limit of normal was defined using selected healthy Caucasian blood donors. Given the global rise in obesity and different body habitus in Asians, we aimed to perform a systematic review and meta-analysis combined with bootstrap modeling and individual patient data validation to estimate the ALT upper threshold for Asians, including the overweight and diabetics. We included studies from PubMed, Embase, and Cochrane database searches that identified individuals without known liver diseases (i.e., viral hepatitis, alcohol, and ultrasound-detected nonalcoholic fatty liver disease). The mean ALT (U/L) was estimated using a random-effects mixed model and upper threshold (95th-percentile value, U/L) via a bootstrap model with 10,000 resamples. We screened 4,995 studies and identified 86 studies that reported ALT values for 526,641 individuals without excessive alcohol intake or known liver diseases, yielding a mean ALT of 19 and ALT upper threshold of 32. The ALT upper threshold was 37 in males versus 31 in females, 39 in overweight versus 28 in normal-weight individuals, and 36 for diabetics versus 33 for nondiabetics. We validated our study level data with individual patient level data in 6,058 individuals from five study centers in Japan. Consistent with our study-level data, we found that the ALT upper threshold in our individual patient data analysis was indeed higher in overweight versus normal-weight individuals (39 vs. 32) and in diabetics versus nondiabetics (42 vs. 33). Conclusion: We provide validated reference ranges for ALT upper threshold derived from Asians without known liver disease, including individuals with ultrasound-detected nonalcoholic fatty liver disease who are normal weight, overweight, nondiabetic, and diabetic, to inform practice.

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.

Low Alanine Aminotransferase Cut-Off for Predicting Liver Outcomes; A Nationwide Population-Based Longitudinal Cohort Study

BACKGROUND AND AIM

Recent practice guidelines suggest healthy normal alanine aminotransferase (ALT) levels should be less than 30 U/L for males and 19 U/L for females. We tried to validate the prediction power of the "low cut off" for liver related outcomes in the general population.

METHODS

A total of 426,013 subjects were followed up for 10 years using the National Health Screening Cohort database. Prediction ability of long term mortality and liver related outcomes between conventional (<40 U/L in men and women) and low (<30 U/L in men and <19 U/L in women) ALT cut-off values were compared.

RESULTS

Both conventional and low ALT cut-offs predicted liver related unfavorable outcomes in Kaplan-Meier analysis. Following adjustment for age, body mass index, smoking, exercise, alcohol consumption, fasting blood glucose, and cholesterol via multivariate Cox regression, abnormal ALT using new 'low ALT cut off' was a significant independent predictor for liver-related mortality, HCC, and decompensated liver events. When the low cut-off criteria were added to the prediction model, the ability to predetect liver-related hard outcomes significantly increased in both men and women (p-values < 0.0001). The C-index values for predicting liver-related adverse events were the same in both ALT cut-offs, after adjusting confounding factors (C index value: 0.73~0.88).

CONCLUSIONS

New low ALT cut-off showed good prediction power for liver related unfavorable outcomes.

Low Alanine Aminotransferase Levels in the Elderly Population: Frailty, Disability, Sarcopenia, and Reduced Survival

Background

Although low alanine aminotransferase (ALT) levels have been associated with poor outcomes in the elderly population, the determinants subtending this association have been poorly explored. To gain insight into this topic, we analyzed data from a prospective population-based database (InCHIANTI study) in which frailty, disability, sarcopenia, and pyridoxine levels were systematically assessed.

Methods

Data are from 765 participants aged more than 65 years (mean age 75.3 years, women 61.8%), without chronic liver disease, malignancies, or alcohol abuse. Frailty was defined according to Fried criteria, sarcopenia through peripheral Quantitative-Computed-Tomography (lowest gender-specific tertile of the residuals of a linear regression of muscle mass from height and fat mass), and disability as self-reported need for help in at least one basic daily living activity. Associations of ALT with overall and cardiovascular mortality were assessed by Cox-models with time-dependent covariates.

Results

ALT activity was inversely associated with frailty, sarcopenia, disability, and pyridoxine deficiency; however, higher ALT was confirmed to be protective with respect of overall and cardiovascular mortality even in multiple-adjusted models including all these covariates (overall: hazard ratio [HR] 0.98 [0.96-1], p = .02; cardiovascular: 0.94 [0.9-0.98], p < .01). The association between ALT activity and mortality was nonlinear (J-shaped), and subjects in the lower quintiles of ALT levels showed a sharply increased overall and cardiovascular mortality.

Conclusions

These results suggest that reduced ALT levels in older individuals can be considered as a marker of frailty, disability, and sarcopenia, and as an independent predictor of adverse outcomes. The possible relationship between reduced ALT and impaired hepatic metabolic functions should be explored.

The correlation between fatty liver disease and chronic kidney disease

BACKGROUND/PURPOSE

The impact of non-alcoholic fatty liver disease (NAFLD) on the prevalence of chronic kidney disease (CKD) is not fully elucidated. We aimed to assess the correlation between NAFLD and CKD in a large population study.

METHODS

We included consecutive subjects who had received health check-up service at Taipei Veterans General Hospital from 2002 to 2009. NAFLD was diagnosed with abdominal ultrasound, and advanced liver fibrosis was determined with NAFLD fibrosis score (NAFLD-FS). CKD was defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m².

RESULTS

Among the 29,797 subjects enrolled in this study, NAFLD and CKD were diagnosed in 44.5% and 20.2% of the population, respectively. Subjects with NAFLD had a higher proportion of CKD compared to those without NAFLD (24.1% vs. 17.1%, p < 0.001). However, NAFLD was not related to CKD with an odds ratio (OR) of 1.015 (95% confidence interval [CI] 0.954-1.081, p = 0.630) after multivariate analyses. Nevertheless, further analyses revealed that among patients with NAFLD, those with advanced fibrosis were more likely to have CKD after adjusting for confounding factors (OR 2.284, 95% CI 1.513-3.448, p < 0.001).

CONCLUSION

NAFLD per se was not a risk factor for CKD, but NAFLD patients with advanced fibrosis faced a higher possibility of CKD. Hence, patients with NAFLD and advanced fibrosis should be screened for CKD and prompted to receive treatment if the diagnosis was made.

Eight weeks of Paritaprevir/r/Ombitasvir + Dasabuvir in HCV genotype 1b with mild-moderate fibrosis: Results from a real-world cohort

BACKGROUND & AIMS

The interferon-free regimen paritaprevir/ritonavir, ombitasvir + dasabuvir (PTV/r/OBV/DSV) has shown high efficacy in patients with hepatitis C virus (HCV) genotype 1b infection when administered for 8 or 12 weeks, but data regarding the 8-week treatment are scarce. The aim of our study was to assess the efficacy and safety of the 8-week administration of PTV/r/OBV/DSV in a real-world cohort.

METHODS

We performed a multicentre observational study from Spanish Hepa-C database including patients receiving 8 weeks of PTV/r/OBV/DSV (October 2016-November 2017). Those with advanced fibrosis, with non-genotype 1b or who were treatment-experienced were excluded.

RESULTS

A total of 211 patients were registered from 23 Spanish centres; eleven were excluded. At baseline, 42.5% (n = 85) were male, median (range) age was 57 (23-86), ALT was 45 (11-494) IU/mL, viral load was 6.1 (3.3-8.2) log10 IU/mL, and 74.5% had mild liver fibrosis (F0-F1) and 25.5% moderate fibrosis (F2). At the end of treatment (EOT), HCV viral load was undetectable in 100% (200/200). Seven patients relapsed after treatment discontinuation. Sustained virological response (SVR12) rates by intention-to-treat analysis were 96% (192/200). Regarding treatment safety, 2 patients developed ALT elevation >5x ULN, but there were no treatment discontinuations. One patient died 7 weeks after EOT.

CONCLUSION

Treatment with PTV/r/OBV/DSV in genotype 1b-infected treatment-naive patients with mild-moderate fibrosis shows excellent efficacy and safety in real life, similarly to clinical trials. Clinicaltrials.gov, number: NCT03122132.

Factors associated with reverse change of serum ALT activity in patients with chronic hepatitis B

AIM

To investigate the factors associated with the reverse change of serum alanine aminotransferase (ALT) activity in patients with chronic hepatitis B.

METHODS

The clinical information of 516 patients with chronic hepatitis B treated from September 2010 to September 2015 was collected. The patients with serum ALT activity ≤ 40 IU/L were divided into a study group, while those with serum ALT activity > 40 IU/L was assigned to a control group.

RESULTS

The reverse change rate of ALT activity was 25.78% (133/516) in chronic hepatitis B patients. The reverse change rate of ALT activity was 51.18% (65/127) in the population with combined cirrhosis, significantly higher than that of patients without cirrhosis (17.48%, P < 0.05). Compared to the control group, serum albumin, direct bilirubin, indirect bilirubin, total bile acids, potassium, sodium, calcium, and triglycerides in the study group were significantly lower, while serum globulin and uric acid were significantly higher (P < 0.05). Multivariate unconditional logistic regression analysis showed that cirrhosis and serum uric acid were positively associated with the reverse change of ALT activity (P < 0.05), while serum albumin, total bile acids, potassium, calcium, and chloride were negatively correlated with the reverse change of ALT activity (P < 0.05).

CONCLUSION

Combined liver cirrhosis, increased serum globulin and uric acid, and declined serum albumin, direct bilirubin, indirect bilirubin, total bile acid, potassium, calcium, triglyceride, and chloride may be factors influencing the reverse change of serum ALT activity. When serum ALT activity is not consistent with clinical symptoms of chronic hepatitis B, attention should be paid to these factors as well.

Nonalcoholic fatty liver disease: current concepts, epidemiology and management strategies

Nonalcoholic fatty liver disease (NAFLD) is now the most prevalent liver disease in the world. It involves a spectrum of conditions from hepatic steatosis to nonalcoholic steatohepatitis and liver fibrosis, and is a major cause of cirrhosis and hepatocellular carcinoma. It is defined by presence of steatosis in 5% of hepatocytes or more in the absence of other causes of fatty liver. The metabolic syndrome is the major known risk factor for NAFLD. Dietary contributors such as high fructose intake and coffee consumption appear to increase and decrease the risk of disease respectively, but these links are unclear. Genetic associations have also been identified. The estimated prevalence of the disease varies according to diagnostic method and population demographics. It appears to be a major issue in Europe with population studies showing up to 50% of the individuals are affected while in the USA one in three adults are estimated to have NAFLD. Laboratory investigations and ultrasound are typically first-line investigations. Fibrosis may be assessed noninvasively through transient elastography and biomarkers but liver biopsy remains the gold standard to quantify hepatic damage. Associated comorbidities include cardiovascular disease and chronic kidney disease. Weight loss, dietary changes and exercise are recommended in management. Medications should be considered to manage underlying risk factors including insulin resistance. Surgical options include bariatric procedures and liver transplantation. The combination of rising prevalence and significant potential complications warrant further research into NAFLD, particularly in areas with research gaps including Eastern Europe.

Nonalcoholic fatty liver disease with elevated alanine aminotransferase levels is negatively associated with bone mineral density: Cross-sectional study in U.S. adults

Background

Nonalcoholic fatty liver disease (NAFLD) has been reported to have a negative effect on bone mineral density (BMD) in Asian populations. Whether such an association exists in Western populations is less clear.

Methods

This cross-sectional analysis of data from NHANES III, a United States national health survey conducted from 1988 to 1994, included 6089 participants aged 40–75 years, selected after excluding people with hepatitis virus serology, elevated alcohol consumption, decreased renal function, or steroid use, and pregnant females. The main outcome, BMD at the femoral neck, was measured using dual-energy X-ray absorptiometry. The primary exposure, NAFLD, was defined as moderate or severe hepatic steatosis diagnosed using abdominal ultrasonography.

Result

After controlling for gender and menopausal status, race/ethnicity, age and body mass index, NAFLD was not significantly associated with BMD (beta coefficient: −0.006, 95%CI: −0.016, 0.003). A secondary analysis categorized participants with NAFLD according to their serum alanine aminotransferase (ALT) levels into high and normal ALT NAFLD groups, and compared these with the non-NAFLD group. NAFLD with higher levels of ALT was associated with lower levels of BMD (beta coefficient: −0.023, 95% CI: −0.044, −0.002).

Conclusion

This study showed a relationship between NAFLD with high ALT and lower BMD in the general U.S. population.

Duration-response association between exercise and HDL in both male and female Taiwanese adults aged 40 years and above

BACKGROUND

Exercise is an important cardiovascular risk reducing therapy.

OBJECTIVE

The aim of this study was to assess the relationship between weekly exercise duration and high-density lipoprotein cholesterol (HDL-c) in Taiwanese men and women.

METHODS

Data were retrieved from the dataset of the national adult preventive medical services which is recorded under the Health Promotion Administration (HPA). The lipid profiles of 194528 eligible participants aged 40 years and above who completed a questionnaire on recent health behavior including smoking, drinking, exercise and other factors in 2014 were determined. Weekly exercise durations of 0.0, <2.5 and ≥2.5 hours were classified as no, below recommended and recommended, respectively. The relationship between exercise and HDL-c was determined using linear regression.

RESULTS

After multivariate adjustments, a duration-response association existed between exercise and HDL-c (P-trend <0.0001) in both sexes. Weekly exercise durations of <2.5 and ≥2.5 hours were both positively associated with HDL-c (P <0.0001) in both sexes. However, the associations were stronger in males than females in both exercise groups. Smoking (P <0.05) and BMI (P <0.0001) were negatively associated while drinking was positively associated with HDL-c in both sexes.

CONCLUSION

This study demonstrated a duration-response association between exercise and HDL-c. Exercise at durations below the minimum weekly recommendation of 2.5 hours was positively associated with HDL-c.

Diagnostic accuracy of serum alanine aminotransferase as biomarker for nonalcoholic fatty liver disease and insulin resistance in healthy subjects, using 3T MR spectroscopy

Recognition of the close relationship of nonalcoholic fatty liver disease (NAFLD) with diabetes mellitus 2, obesity, metabolic syndrome, and cardiovascular disease has stimulated growing interest in NAFLD as a public health problem. Serum alanine aminotransferase (ALT) has been proposed as a marker of NAFLD, but levels are within the range currently considered "normal" in a large proportion of NAFLD subjects.The aim of the study was to determine the diagnostic accuracy of serum ALT for identifying individuals with NAFLD, using 3-Tesla (T) magnetic resonance spectroscopy (H-MRS).A cross-sectional study was conducted in 129 healthy subjects. Liver triglyceride content was quantified by H-MRS. NAFLD was defined as liver triglyceride content greater than 5.56%.Liver triglyceride content was >5.56% in 79 participants (NAFLD) and lower in the remaining 50 (normal). Serum ALT levels correlated positively with liver triglyceride content (r = 0.58, P < .001), Homeostatic Model Assessment for Insulin Resistance (r = 0.32, P < .01), and fasting insulin (r = 0.31, P < .01), and inversely correlated with adiponectin (r = 0.35, P < .01) and high-density lipoprotein cholesterol (r = 0.32, P < .01). Regression analysis showed that serum ALT was the best predictor of NAFLD (P < .01). Optimal serum ALT cut-off to predict NAFLD was 23 IU/L (area under receiver-operating characteristic curve: 0.93; sensitivity: 0.94; specificity: 0.72).This study shows that serum ALT is a sensitive and accurate biomarker of NAFLD if the "normal" ALT value is revised and established at a lower level. An ALT threshold of 23 IU/L identified 94% of individuals with NAFLD in the present series, using 3-T H-MRS for liver triglyceride quantification.

Fatty Liver Index and Lipid Accumulation Product Can Predict Metabolic Syndrome in Subjects without Fatty Liver Disease

Background. Fatty liver index (FLI) and lipid accumulation product (LAP) are indexes originally designed to assess the risk of fatty liver and cardiovascular disease, respectively. Both indexes have been proven to be reliable markers of subsequent metabolic syndrome; however, their ability to predict metabolic syndrome in subjects without fatty liver disease has not been clarified. Methods. We enrolled consecutive subjects who received health check-up services at Taipei Veterans General Hospital from 2002 to 2009. Fatty liver disease was diagnosed by abdominal ultrasonography. The ability of the FLI and LAP to predict metabolic syndrome was assessed by analyzing the area under the receiver operating characteristic (AUROC) curve. Results. Male sex was strongly associated with metabolic syndrome, and the LAP and FLI were better than other variables to predict metabolic syndrome among the 29,797 subjects. Both indexes were also better than other variables to detect metabolic syndrome in subjects without fatty liver disease (AUROC: 0.871 and 0.879, resp.), and the predictive power was greater among women. Conclusion. Metabolic syndrome increases the cardiovascular disease risk. The FLI and LAP could be used to recognize the syndrome in both subjects with and without fatty liver disease who require lifestyle modifications and counseling.

Dose-Response Relationship between Alanine Aminotransferase Levels within the Reference Interval and Metabolic Syndrome in Chinese Adults

PURPOSE

Elevation in serum alanine aminotransferase (ALT) levels is a biomarker for metabolic syndrome (MS); however, the relationship has not been fully investigated within the reference interval of ALT levels. Our objective was to explore the relationship between serum ALT levels within the reference interval and MS in Chinese adults.

MATERIALS AND METHODS

This cross-sectional study included 16028 adults, who attended routine health check-ups at Shengli Oilfield Central Hospital from January 2006 to March 2012. The reference interval of serum ALT level was defined as less than 40 U/L. Logistic regression models and restricted cubic spline were used to evaluate the association of ALT with MS.

RESULTS

The prevalence of MS in the total population was 13.7% (6.4% for females and 18.4% for males). Multiple logistic regression showed that ALT levels were positively associated with MS after adjustment for potential confounding factors. The odds ratio of MS in the top quartile was 4.830 [95% confidence interval (CI): 2.980-7.829] in females and 3.168 (95% CI: 2.649-3.790) in males, compared with the ALT levels in the bottom quartile. The restricted cubic spline models revealed a positive non-linear dose-response relationship between ALT levels and the risk of MS in women (p for nonlinearity was 0.0327), but a positive linear dose-response relationship in men (p for nonlinearity was 0.0659).

CONCLUSION

Serum ALT levels within the reference interval are positively associated with MS in a dose-response manner. Elevated ALT levels, even within the reference interval, may reflect early dysmetabolic changes.

The intersection of nonalcoholic fatty liver disease and obesity

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide and recently emerged as the most rapidly increasing indication for liver transplant. Although obesity is a risk factor for NAFLD, overlap between these two entities is incompletely understood. We highlight recent insights into the pathogenesis of human NAFLD in relation to obesity and discuss advances in the diagnosis and treatment of NAFLD.

Shenfu decoction as adjuvant therapy for improving quality of life and hepatic dysfunction in patients with symptomatic chronic heart failure

ETHNOPHARMACOLOGICAL RELEVANCE

Shenfu decoction (SFD) is a water extract of the dried root or root stalk of Panax ginseng C. A. Mey (Asian ginseng) and the lateral root of Aconitum carmichaeli Debx (prepared by Fuzi, Heishunpian in Chinese). It has been used to treat heart failure for over a thousand years. The main active components of SFD, ginsenosides and higenamine, enhance heart contractility, increase the coronary blood supply, improve ischemic myocardial metabolism, scavenge free radicals and protect myocardial ultrastructure.

AIM OF THE STUDY

To investigate the effect of SFD on quality of life (QOL) and hepatic function in symptomatic chronic heart failure (CHF) patients.

MATERIALS AND METHODS

Forty patients enrolled in the study were randomized into two groups: an SFD group (18 cases) and a control group (22 cases). All the patients received standard heart failure therapy, and the SFD group patients were also treated with Shenfu granules for 14 days as an adjunctive therapy. The effects of SFD on QOL, plasma alanine aminotransferase (ALT) level, cardiac function, left ventricular ejection fraction (LVEF) and tumor necrosis factor-α (TNF-α) level were studied. ALT threshold in hepatic injury are 21U/L for men and 17U/L for women.

RESULTS

Minnesota Living with Heart Failure Questionnaire (MLHFQ) scores were improved by 35.27±10.72 vs. 23.87±11.96 in the SFD and control groups respectively (p<0.01). Subgroup analysis of the MLHFQ results demonstrated that both physical and emotional scores were significantly higher in the SFD group (21.00±5.66 vs. 16.75±6.25, p<0.05; 4.64±4.84 vs. 1.13±2.85, p<0.05). Circulating ALT was significantly decreased by SFD (13.3IU/L vs. 0.6IU/L, p<0.01). The grading of cardiac function and LVEF were increased by 1.6±0.5 vs. 1.1±0.3 and 18%±13% vs. 8%±8% in the SFD and control groups respectively (p<0.05 and p<0.05). The level of TNF-α declined more in SFD than control group (64.8±5.0 to 57.6±4.1, p<0.05; vs. 61.6±5.9 vs. 57.7±3.2. p>0.05).

CONCLUSION

Compared with standard heart failure treatment, oral SFD as an adjuvant therapy significantly improved QOL and hepatic injury in CHF patients.

Changing hepatitis D virus epidemiology in a hepatitis B virus endemic area with a national vaccination program

The emergence of hepatitis D virus (HDV) infection in the era of widespread HBV vaccination has not been described before. We aimed to investigate the changing epidemiology of HDV infection among high- and low-risk populations after an outbreak of human immunodeficiency virus (HIV) infection among injection drug users (IDUs) in Taiwan. A prospective, multicenter, cohort study of 2,562 hepatitis B surface antigen (HBsAg)-positive individuals was conducted to determine the prevalence, genotype, and risk factors of HDV infection from 2001 through 2012. The prevalence rates of HDV infection were 74.9%, 43.9%, 11.4%, 11.1%, and 4.4% among HIV-infected IDUs, HIV-uninfected IDUs, HIV-infected men who have sex with men, HIV-infected heterosexuals, and the general population of HBsAg-positive subjects, respectively. A significant increase in the trend of HDV prevalence from 38.5% to 89.8% was observed in HIV-infected IDUs (odds ratio = 3.06; 95% confidence interval: 1.68-5.56; P = 0.0002). In multivariate analysis, injection drug use, hepatitis C virus infection, HIV infection, serum HBsAg level ≧250 IU/mL, duration of drug use, and older age were significant factors associated with HDV infection. HDV genotype IV (72.2%) was the prevalent genotype circulating among IDUs, whereas genotype II was predominant in the non-IDU populations (73.3%). In the HIV cohort born after 1987 who were HBsAg negative, over half (52.9%) had antibody to hepatitis B surface antigen antibody levels of <10 mIU/mL and there was a significantly higher HBsAg seroprevalence in the HIV cohort, compared to the control group (8.1% vs. 0.0%; P = 0.02).

CONCLUSION

In the era of HBV vaccination, IDUs and HIV-infected individuals have emerged as high-risk groups and a reservoir for HDV infection. Effective strategies are needed to curb the reemerging epidemic of HDV infection in these high-risk groups.

Redefining the alanine aminotransferase upper limit of normal improves the prediction of metabolic syndrome risk

BACKGROUND

Multiple studies have recently proposed the lowering of upper limit of normal (ULN) for alanine aminotransferase (ALT) to improve the diagnostic sensitivity for viral hepatitides and metabolic syndrome (MS). We have tried to validate some of the proposed ULNs in the diagnosis of MS.

METHODS

We used data from the HepaMeta Study conducted in 2011 in Slovakia, which explored the prevalence of MS in eastern Slovakia. Patients were tested for the criteria of MS and ALT. Different, previously published, ALT cutoffs were then used to calculate odds' ratios, sensitivity, specificity, and accuracy of MS and its components.

RESULTS

Manufacturers' recommended ULN used in our institution (0.8 µkat/l, 47 U/l for men and 0.6 µkat/l, 35 U/l for women) failed to predict any significant risk of MS. Lowered cutoff (72% of the original ULN) identified the patients with the highest age-adjusted probability of MS (odds ratio 3.194, 95% confidence interval 1.398-7.295). ALT was significantly associated with elevated levels of triacylglycerols, hyperglycemia, and obesity.

CONCLUSION

In patients with MS, one must consider liver involvement if the patient has ALT levels in the upper third of the reference range. There is the need for discussion about the feasibility of lower ALT ULN in clinical practice.

External validation of fatty liver index for identifying ultrasonographic fatty liver in a large-scale cross-sectional study in Taiwan

Background and Aims

The fatty liver index (FLI) is an algorithm involving the waist circumference, body mass index, and serum levels of triglyceride and gamma-glutamyl transferase to identify fatty liver. Although some studies have attempted to validate the FLI, few studies have been conducted for external validation among Asians. We attempted to validate FLI to predict ultrasonographic fatty liver in Taiwanese subjects.

Methods

We enrolled consecutive subjects who received health check-up services at the Taipei Veterans General Hospital from 2002 to 2009. Ultrasonography was applied to diagnose fatty liver. The ability of the FLI to detect ultrasonographic fatty liver was assessed by analyzing the area under the receiver operating characteristic (AUROC) curve.

Results

Among the 29,797 subjects enrolled in this study, fatty liver was diagnosed in 44.5% of the population. Subjects with ultrasonographic fatty liver had a significantly higher FLI than those without fatty liver by multivariate analysis (odds ratio 1.045; 95% confidence interval, CI 1.044–1.047, p< 0.001). Moreover, FLI had the best discriminative ability to identify patients with ultrasonographic fatty liver (AUROC: 0.827, 95% confidence interval, 0.822–0.831). An FLI < 25 (negative likelihood ratio (LR−) 0.32) for males and <10 (LR− 0.26) for females rule out ultrasonographic fatty liver. Moreover, an FLI ≥ 35 (positive likelihood ratio (LR+) 3.12) for males and ≥ 20 (LR+ 4.43) for females rule in ultrasonographic fatty liver.

Conclusions

FLI could accurately identify ultrasonographic fatty liver in a large-scale population in Taiwan but with lower cut-off value than the Western population. Meanwhile the cut-off value was lower in females than in males.

Factors associated with significant liver fibrosis assessed using transient elastography in general population

AIM: To investigate the prevalence of significant liver fibrosis assessed using transient elastography (TE) and its predictors in asymptomatic general population.

METHODS: A total of 159 subjects without chronic viral hepatitis who underwent comprehensive medical health check-up between January 2012 and July 2012 were prospectively recruited. Significant liver fibrosis was defined as liver stiffness value > 7.0 kPa.

RESULTS: The mean age and body mass index (BMI) of the study population (men 54.7%) was 56.0 years and 24.3 kg/m². Among the study subjects, 11 (6.9%) showed significant liver fibrosis. On univariate analysis, BMI, alanine aminotransferase (ALT), homeostasis model assessment of insulin resistance, carotid intimal media thickness (IMT), number of calcified plaques on carotid ultrasound, and visceral fat area on computed tomography were significantly higher in subjects with significant liver fibrosis than in those without (all P < 0.05). However, on multivariate analysis, BMI [odds ratio (OR) =1.487; P = 0.045], ALT (OR = 1.078; P = 0.014), carotid IMT (OR = 3.244; P = 0.027), and the number of calcified carotid plaques (OR = 1.787; P = 0.031) were independent predictors of significant liver fibrosis.

CONCLUSION: The prevalence of significant liver fibrosis assessed using TE was 6.9% in apparently healthy subjects. High BMI, high ALT, thicker carotid IMT, and higher numbers of calcified carotid plaques were independently associated with the presence of significant liver fibrosis.

Upper limit of normal serum alanine aminotransferase levels in Japanese subjects

AIM

Serum alanine aminotransferase (ALT) is important for screening, diagnosis and management of chronic liver diseases. The incidence of non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH), which is considered a hepatic manifestation of lifestyle-related diseases, is increasing worldwide. However, the upper limit of the normal ALT level has not yet been established because of not excluding many lifestyle-related diseases. The aim of this study was to evaluate the upper limit of normal serum ALT levels in Japanese subjects.

METHODS

We analyzed the serum ALT levels of 11 404 Japanese subjects negative for hepatitis B surface antigen and hepatitis C virus antibody, and who received health check-ups. Lifestyle factors related to ALT levels were determined by multivariate analysis. Subjects with all factors identified by multivariate analysis within the normal range were defined as "healthy" subjects. The 90th percentile of ALT levels in healthy subjects was defined as the upper limit of normal ALT.

RESULTS

Whereas alcohol intake was not a significant factor, the following were independently associated with ALT concentration by multivariate analysis: sex; age; body mass index; waist circumference; concentrations of total cholesterol, high-density lipoprotein cholesterol, triglycerides and fasting blood glucose; and fatty liver on ultrasonography. Healthy subjects consisted of 1462 (21.2%) men and 2046 (45.4%) women, and the 90th percentiles of the ALT levels in the two groups were 29 and 23 IU/L, respectively.

CONCLUSION

The upper limits of normal ALT when considering lifestyle factors in Japanese subjects were 29 IU/L in men and 23 IU/L in women.

Determinants of alanine aminotransferase levels in a large population from Southern Italy: relationship between alanine aminotransferase and age

BACKGROUND

Determinants of alanine aminotransferase levels have never been investigated in real-life settings. The relationship between alanine aminotransferase and age remains controversial. We evaluated epidemiological, anthropometric, and metabolic factors associated with alanine aminotransferase, focusing on the relationship between alanine aminotransferase and age.

METHODS

A 5-year retrospective analysis was performed on data recorded by 120 general practitioners from Naples (Italy), caring for 170,000 subjects. Exclusion criteria were age <18 years, diagnosis of chronic liver disease, positive markers for viral hepatitis, alcohol abuse, and alanine aminotransferase >100UI/L.

RESULTS

44,232 subjects were enrolled (42.7% males, mean age 56±18 years). Alanine aminotransferase showed independent direct associations with body mass index, glycaemia, cholesterol, and triglycerides (p<0.001), and inverse associations with high-density lipoprotein cholesterol (p<0.001) and creatinine (p<0.01). The relationship between alanine aminotransferase and age was better expressed by polynomial regression (r=0.18, p<0.001), creating an inverted parabola. Mean alanine aminotransferase increased until the third decade in males and the fifth in females, with a subsequent progressive decrease in both genders. The inverse association between alanine aminotransferase and age in older subjects was independent from metabolic factors.

CONCLUSIONS

This real-life setting study, supports the concept that dysmetabolism is a strong determinant of liver injury. Based on our data, a reduction of the standard upper limit of normal alanine aminotransferase should be considered for older subjects.

Elevated levels of alanine transaminase and triglycerides within normal limits are associated with fatty liver

In the present study, the threshold values of laboratory data for the diagnosis of non-alcoholic fatty liver disease (NAFLD) were investigated. The study enrolled patients who had undergone abdominal ultrasound (US) between April 2013 and August 2013, and for whom laboratory data were available on the same day. NAFLD was diagnosed following observations of a bright liver or hepatorenal echo contrast on the abdominal US scans. Patients were excluded from the study if they had liver diseases or had been prescribed prednisolone or methotrexate. Receiver operating characteristic curves, the Wilcoxon signed-rank test and Fisher's exact probability test were used for data analysis. In total, 80 NAFLD and 94 non-NAFLD patients were enrolled in the study. The threshold levels of alanine aminotransferase (ALT) and triglyceride (TG) for the diagnosis of NAFLD were 19.0 IU/l and 101 mg/dl, respectively. Patients were divided into two groups according to the levels of ALT and TG. Those with ALT levels of >19 IU/l and TG levels of >101 mg/dl were defined as the positive group, while the remaining patients were classified as the negative group. The specificity and positive predictive value using the combined threshold levels of ALT >19 IU/l and TG >101 mg/dl were 80.9 and 75.0%, respectively. Therefore, the results indicated that ALT levels of >19 IU/l or TG levels of >101 mg/dl were useful markers for the screening of NAFLD. However, NAFLD was more strongly suspected in patients with ALT levels of >19 IU/l and TG levels of >101 mg/dl.

Characterizing severe obesity in children and youth referred for weight management

Background

Severe obesity (SO) in pediatrics has become increasing prevalent in recent decades.

The objective of our study was to examine differences in demographic, anthropometric, cardiometabolic, and lifestyle variables in children and youth with SO versus their less overweight/obese (OW/OB) peers.

Methods

A retrospective medical record review of 6-19 year old participants enrolled in an outpatient pediatric weight management clinic was conducted. SO (body mass index [BMI] ≥99^th percentile) and OW/OB (BMI ≥85^th and <99^th percentile) groups were created according to Centers for Disease Control and Prevention definitions. Demographic, anthropometric, cardiometabolic and lifestyle data reported at baseline (pre-intervention) were retrieved.

Results

Of the 345 participants, most were girls (56.2%), Caucasian (78.7%), and had family incomes > $50,000/year (65.7%). The SO group (n = 161) had lower HDL-cholesterol and higher liver enzymes, insulin resistance and blood pressure than the OW/OB group (n = 184; all p < 0.01). They also reported higher total energy intakes, fewer steps/day, less moderate-to-vigorous physical activity, and more leisure time screen time (all p < 0.02) than their leaner peers. Compared to the OW/OB group, a higher proportion of individuals in the SO group possessed cardiometabolic risk factors, including high triglycerides (45.8% vs 58.5%), alanine aminotransferase (55.4% vs 81.4%), insulin resistance (55.6% vs 82.1%), systolic blood pressure (11.5% vs 27.3%), diastolic blood pressure (17.8% vs 30.0%), and low HDL-cholesterol (44.6% vs 64.6%; all p < 0.02). Aside from the ~75% of participants (groups combined) who met the daily recommended intakes of grain and meat products, <50% of boys and girls met any of the remaining nutrition and physical activity-related recommendations. Compared to the OW/OB group, greater proportions of children and youth in the SO group failed to meet moderate-to-vigorous physical activity (48.4% vs 31.9%) and leisure-time-screen-time recommendations (43.4% vs 28.3%; both p < 0.05).

Conclusion

Children and youth with SO have a worse cardiometabolic profile and less favorable lifestyle habits than their OW/OB peers. These differences emphasize the heightened obesity-related health risks associated with SO in the pediatric years.

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.

From NAFLD in clinical practice to answers from guidelines

This review of the literature consists of three sections. First, papers concerning non-alcoholic fatty liver disease (NAFLD) awareness among the general population, general practitioners, and liver and non-liver specialists were retrieved and analyzed to highlight the perception of disease, verify knowledge of current recommendations, and identify the main difficulties experienced in clinical practice. Next, position papers and clinical practice guidelines issued by International and National Hepatological Scientific Societies were identified and critically assessed in order to pinpoint the areas of convergence/difference. Finally, practical suggestions on NAFLD diagnosis and management in daily practice are provided and the open questions highlighted.

Inverse association between hepatitis B virus infection and fatty liver disease: a large-scale study in populations seeking for check-up

Background

Although many studies have attempted to clarify the association between hepatitis B virus (HBV) infection and fatty liver disease, no prior studies have emphasized the relationship of HBV and fatty liver regarding different demographics of age and body mass index (BMI).

Aim

To investigate the correlation of HBV and fatty liver in the different demographics of age and BMI.

Methods

We enrolled consecutive subjects who had received health check-up services at the Taipei Veterans General Hospital from 2002 to 2009 and ultrasonography was used to diagnose fatty liver according to the practice guidelines of the American Gastroenterological Association.

Results

Among the 33,439 subjects enrolled in this study, fatty liver was diagnosed in 43.9% of the population and 38.9% of patients with chronic HBV infection. Multivariate analysis showed that BMI, age, waist circumference, systolic blood pressure, fasting glucose, cholesterol, alanine aminotransferase (ALT) levels, and platelet counts were positively associated, while hepatitis B surface antigen (HBsAg) positivity was inversely associated with fatty liver, especially for subjects with BMI>22.4 kg/m² and age>50 years. On the contrary, HBV infection was positively correlated with the presence of elevated serum ALT levels in subjects with fatty liver disease regardless of their age and BMI.

Conclusions

Metabolic factors are important determinants for the prevalence of fatty liver. Patients with HBV infection were inversely associated with fatty liver disease than the general population, especially in older and obese patients. Furthermore, metabolic factors and HBV infection were associated with elevated serum ALT levels in fatty liver disease.

Upper limit of normal for alanine aminotransferase: quo vadis?

Several studies suggest that a substantial number of patients with normal serum alanine aminotransferase (ALT) levels, defined by current thresholds, have ongoing hepatic necro-inflammation and fibrosis, and are at risk of liver disease progression. A major problem lies in the definition of normality. The current upper limit of normal (ULN) for ALT was established in the 1980s when reference populations were likely to include many persons with hepatitis C virus infection and nonalcoholic fatty liver disease. Because ALT may be influenced, not only by liver disease, but also by other medical conditions, changing lifestyle factors and demographic determinants, the current ALT ULN threshold has recently been challenged. This review not only highlights current evidence on why and how ALT ULN should be redefined, but also discusses the current concerns about updating the ULN threshold for ALT.