Intermethod calibration of alanine aminotransferase (ALT) and γ-glutamyltransferase (GGT) results: application to Fibrotest® and Actitest® scores

Higher gamma-glutamyl transferase levels are associated with an increased risk of incident systemic sclerosis: a nationwide population-based study

Gamma-glutamyl transferase (GGT) is known to promote oxidative stress. As oxidative stress is a key component in the pathogenesis of systemic sclerosis (SSc), we investigated whether GGT levels are associated with the risk of incident SSc. A cohort of individuals without SSc who underwent national health examination in 2009 were extracted from the Korean National Health Insurance Service database. The incidence rate of SSc during the observation period, between 2009 and 2019, was estimated. GGT levels measured in 2009 were categorized into quartiles (Q1 [lowest], Q2, Q3, and Q4 [highest]). Multivariable Cox proportional hazard models were used to estimate the risk of incident SSc according to the quartiles of GGT, using Q1 as the reference. A total of 6,091,788 individuals were included. Incidence rate of SSc was 1.16 per 100,000 person-years over a mean observation period of 9.2 years. After adjusting for age, sex, body mass index, economic income, smoking status, alcohol consumption, physical activity, hypertension, type 2 diabetes, dyslipidemia, and chronic kidney disease, higher quartiles of GGT levels were significantly associated with a higher risk of incident SSc (Q4: adjusted hazard ratio [aHR] 1.807, 95% confidence interval CI 1.446-2.259; Q3: aHR 1.221, 95% CI 0.971-1.536; and Q2: aHR 1.034, 95% CI 0.807-1.324; p for trend < 0.001). Higher GGT levels were associated with a higher risk of incident SSc. These findings could lead to a closer monitoring for high risk individuals and an earlier diagnosis and treatment.

Correlation between plasma miR-122 expression and liver injury induced by hepatectomy

OBJECTIVE

This study aimed to define the correlation between microRNA-122 (miR-122) expression and hepatectomy-induced liver injury in patients with hepatocellular carcinoma (HCC).

METHODS

Plasma miR-122 expression in patients with HCC and healthy age-matched controls was determined, and correlated with plasma alanine transaminase activity (ALT) and bilirubin levels preoperatively and on days 1 and 7 postoperation. Correlations between plasma miR-122 and clinicopathological characteristics at 1 day postoperation were also determined.

RESULTS

This study included 80 patients with HCC and 80 controls. Baseline expression of miR-122 mRNA and ALT in patients with HCC was significantly higher than in controls. MiR-122 expression correlated with ALT and bilirubin levels preoperatively and on days 1 and 7 postoperatively. In patients with HCC who received a block of the first hepatic portal during surgery and those with excised tumour size >5 cm, plasma miR-122 expression was significantly increased on day 1 postoperatively, compared with expression levels in those who did not receive a block and those with smaller tumours.

CONCLUSIONS

Plasma miR-122 expression is correlated with hepatectomy-induced liver injury in patients with HCC. Increase in miR-122 expression could be used as an index of such injury before and after hepatectomy in these patients.

What are the best reference values for a normal serum alanine transaminase activity (ALT)? Impact on the presumed prevalence of drug induced liver injury (DILI)

BACKGROUND

In clinical research, the definition of the upper limit of normal (ULN) is rarely detailed. For alanine transaminase (ALT), there are several definitions of ULN-ALT but no recognized global reference. Furthermore the inter-laboratory variability of results expressed using ULN-ALT is higher than using the actual value of ULN expressed in IU/L. Regulatory agencies still use ULN-ALT for the definition of drug adverse events such as drug induced liver disease (DILI).

METHODS

We applied two extreme definitions of ULN-ALT (26 and 66 IU/L) in two populations with different liver disease risk: 7463 consecutive volunteers representative a low risk population, and 6865 consecutive patients hospitalized in a tertiary referral center. The same assay technique was used for both populations on fresh plasma in the same laboratory.

RESULTS

In the low risk population the liver disease estimates ranged from 0% to 1.99% according to ULN-ALT definition and gender; prevalence of liver disease as defined by Temple's criteria (3×ULN) decreased significantly with increased ULN-ALT threshold and prevalence of liver disease was lower in females compared to males (all P<0.001). In the high risk population the estimates of liver disease prevalence ranged from 0.78% to 15.85%; disease prevalence using both Temple's corollary and Hy's law criteria (3×ULN-ALT and bilirubin >34 μmol/L) decreased significantly with increased ULN-ALT threshold and females compared to males. In the low risk population the two major factors associated with ULN variability were gender and BMI.

CONCLUSION

Artificial statistical modifications of the procedures chosen for the ULN-ALT definition change dramatically the prevalence of DILI estimates. A consensus in liver disease definitions seems mandatory for DILI studies in order to prevent misleading conclusions.

Applicability and precautions of use of liver injury biomarker FibroTest. A reappraisal at 7 years of age

BACKGROUND

FibroTest (FT) is a validated biomarker of fibrosis. To assess the applicability rate and to reduce the risk of false positives/negatives (RFPN), security algorithms were developed. The aims were to estimate the prevalence of RFPN and of proven failures, and to identify factors associated with their occurrences.

METHODS

Four populations were studied: 954 blood donors (P1), 7,494 healthy volunteers (P2), 345,695 consecutive worldwide sera (P3), including 24,872 sera analyzed in a tertiary care centre (GHPS) (P4). Analytical procedures of laboratories with RFPN > 5% and charts of P4 patients in with RFPN were reviewed.

RESULTS

The prevalence of RFPN was 0.52% (5/954; 95%CI 0.17-1.22) in P1, 0.51% (38/7494; 0.36-0.70) in P2, and 0.97% (3349/345695; 0.94-1.00) in P3. Three a priori high-risk populations were confirmed: 1.97% in P4, 1.77% in HIV centre and 2.61% in Sub-Saharan origin subjects. RFPN was mostly associated with low haptoglobin (0.46%), and high apolipoproteinA1 (0.21%). A traceability study of a P3 laboratory with RFPFN > 5% permitted to correct analytical procedures.

CONCLUSION

The mean applicability rate of Fibrotest was 99.03%. Independent factors associated with the high risk of false positives/negatives were HIV center, subSaharan origin, and a tertiary care reference centre, although the applicability rate remained above 97%.

ActiTest accuracy for the assessment of histological activity grades in patients with chronic hepatitis C, an overview using Obuchowski measure

BACKGROUND

ActiTest (AT) is a biomarker of liver necro-inflammatory histological activity validated in patients with chronic hepatitis C (HCV).

AIM

The aim was to assess the accuracy of AT in comparison with alanine aminotransferase (ALT) the standard of care.

METHODS

Methods used an integrated database of individual data and the new recommended Obuchowski measures. An updated "classical" meta-analysis of AT validation studies was also performed. The main end points were the area under the ROC curves (AUROCs) for the diagnosis of each histological activity grade defined using METAVIR scoring system. To avoid repeated tests and the spectrum effect of activity grades prevalence, the comparison of AT and ALT accuracies used the Obuchowski method.

RESULTS

For the individual analysis, a total of 1250 patients were included and for the meta-analysis six studies (2017 patients) were included. The overall accuracy of AT for the diagnosis of any activity grade (Obuchowski measure=0.850) was significantly higher than the accuracy of ALT (Obuchowski measure=0.837; P=0.009). The updated standard meta-analysis confirmed the accuracy of AT (p<0.0001) both in independent AUROC=0.79 (95% CI, 0.73-0.85) and in non independent studies AUROC=0.74 (95% CI, 0.67-0.81).

CONCLUSIONS

The accuracy of AT for grading the necro-inflammatory activity of patients with HCV was significantly higher than ALT serum activity alone, the standard biomarker.

Biomarkers of liver fibrosis

Liver biopsy, due to its limitations and risks, is an imperfect gold standard for assessing the severity of the most frequent chronic liver diseases. This chapter summarized the advantages and the limits of the available biomarkers of liver fibrosis. Among a total of 2237 references, a total of 14 validated biomarkers have been identified between 1991 and 2007. Nine were not patented and five were patented. FibroTest (FT) was the most studied test with 33 different populations including 6549 patients and 925 controls. The mean diagnostic value for the diagnosis of advanced fibrosis assessed using standardized area under the receiver operating characteristics (ROC) curves was 0.84 [95% confidence interval (CI), 0.83-0.86], without significant difference between the causes of liver disease, hepatitis C, hepatitis B, alcoholic or nonalcoholic fatty liver disease. High-risk profiles of false negative/positive of FT are present in 3% of populations, mainly Gilbert syndrome, hemolysis, and acute inflammation. FT has higher accuracy than aspartate aminotransferase/platelets ratio index (APRI), the most used nonpatented test. No significant difference has been observed between the five patented tests. A quality score has been assessed in order to compare the quality of fibrosis biomarkers. Neither biomarkers nor biopsy are sufficient alone to take definitive decision in a given patient and all the clinical and biological data must be taken into account. Due to the evidence-based data, health authorities in some countries have already approved validated biomarkers as first-line procedure for the staging of liver fibrosis. This overview of evidence-based data suggests that biomarkers could be used as an alternative to liver biopsy for the assessment of fibrosis stage in the four more common chronic liver diseases: C virus (HCV), hepatitis B virus (HBV), hepatitis nonalcoholic fatty liver disease (NAFLD), and alcoholic liver disease (ALD). Neither biomarkers nor biopsy are sufficient alone to take definitive decision in a given patient and all the clinical and biological data must be taken into account.

An accurate definition of the status of inactive hepatitis B virus carrier by a combination of biomarkers (FibroTest-ActiTest) and viral load

BACKGROUND

The combination of transaminases (ALT), biopsy, HBeAg and viral load have classically defined the inactive status of carriers of chronic hepatitis B. The use of FibroTest (FT) and ActiTest (AT), biomarkers of fibrosis and necroinflammatory activity, has been previously validated as alternatives to biopsy. We compared the 4-year prognostic value of combining FT-AT and viral load for a better definition of the inactive carrier status.

METHODS AND FINDINGS

1,300 consecutive CHB patients who had been prospectively followed since 2001 were pre-included. The main endpoint was the absence of liver-related complications, transplantation or death. We used the manufacturers' definitions of normal FT (< = 0.27), normal AT (< = 0.29) and 3 standard classes for viral load. The adjustment factors were age, sex, HBeAg, ethnic origin, alcohol consumption, HIV-Delta-HCV co-infections and treatment.

RESULTS

1,074 patients with baseline FT-AT and viral load were included: 41 years old, 47% African, 27% Asian, 26% Caucasian. At 4 years follow-up, 50 complications occurred (survival without complications 93.4%), 36 deaths occurred (survival 95.0%), including 27 related to HBV (survival 96.1%). The prognostic value of FT was higher than those of viral load or ALT when compared using area under the ROC curves [0.89 (95%CI 0.84-0.93) vs 0.64 (0.55-0.71) vs 0.53 (0.46-0.60) all P<0.001], survival curves and multivariate Cox model [regression coefficient 5.2 (3.5-6.9; P<0.001) vs 0.53 (0.15-0.92; P = 0.007) vs -0.001 (-0.003-0.000;P = 0.052)] respectively. A new definition of inactive carriers was proposed with an algorithm combining "zero" scores for FT-AT (F0 and A0) and viral load classes. This new algorithm provides a 100% negative predictive value for the prediction of liver related complications or death. Among the 275 patients with the classic definition of inactive carrier, 62 (23%) had fibrosis presumed with FT, and 3 died or had complications at 4 year.

CONCLUSION

In patients with chronic hepatitis B, a combination of FibroTest-ActiTest and viral load testing accurately defined the prognosis and the inactive carrier status.

FibroMAX: towards a new universal biomarker of liver disease?

Among the noninvasive alternatives to liver biopsy, several studies have demonstrated the predictive value and a better benefit-to-risk ratio than biopsy of five combinations of simple serum biochemical markers (the super combination being FibroMAX (BioPredictive, Paris, France) in patients at risk of chronic liver diseases: FibroTest (BioPredictive) for the quantitative assessment of fibrosis; SteatoTest (BioPredictive) for the quantitative assessment of steatosis; ActiTest (BioPredictive) for the quantitative assessment of necroinflammatory activity in chronic viral hepatitis C and B; NashTest (BioPredictive) for the categorical diagnosis of nonalcoholic steatohepatitis; and AshTest for the quantitative assessment of alcoholic steatohepatitis (also known in the USA as HCV-FibroSURE, HBV-FibroSURE, ASH-FibroSURE and NASH-FibroSURE; LabCorp, NC, USA). The possible causes of false-negative and false-positive results are also better identified. These tests, which are now available in 50 countries, can facilitate the screening and management of the most frequent liver diseases.

A prospective analysis of the prognostic value of biomarkers (FibroTest) in patients with chronic hepatitis C

BACKGROUND

FibroTest, a noninvasive method of measuring biomarkers of liver fibrosis, is an alternative to liver biopsy for determining the severity of chronic hepatitis C virus (HCV) infection. We compared the 5-year prognostic value of the FibroTest with biopsy staging for predicting cirrhosis decompensation and survival in patients with chronic HCV infection.

METHODS

Fibrosis stage was assessed on the same day by FibroTest and biopsy in a prospective cohort of 537 patients. Disease classification at baseline was 157 patients with severe fibrosis (FibroTest >0.58), 137 with moderate fibrosis (FibroTest 0.32-0.58), and 243 with no or minimal fibrosis (FibroTest <0.32).

RESULTS

In 64 untreated patients with severe fibrosis, survival without HCV complications was 73% [95% confidence interval (CI), 59%-086%; 13 complications], and survival without HCV-related death was 85% (95% CI, 73%-96%; 7 HCV deaths). Survival rates were higher in patients with moderate fibrosis, [99% (95% CI, 97%-100%; 1 complication; P <0.001) and 100% (no HCV death; P <0.001) for patients with and without HCV-related complications, respectively], and in patients with minimal fibrosis [100% (no complication; P <0.001 vs severe) and 100% (no HCV death; P <0.001 vs severe), respectively]. FibroTest was a better predictor than biopsy staging for HCV complications, with area under the ROC curves (AUROC) = 0.96 (95% CI, 0.93%-0.97%) vs 0.91 (95% CI, 0.85%-0.94%; P = 0.01), respectively; it was also a better predictor for HCV deaths: AUROC = 0.96 (95% CI, 0.93%-0.98%) vs 0.87 (95% CI, 0.70%-0.94%; P = 0.046), respectively. The prognostic value of FibroTest was still significant (P <0.001) in multivariate analyses after taking into account histology, treatment, alcohol consumption, and HIV coinfection.

CONCLUSION

The FibroTest measurement of HCV biomarkers has a 5-year prognostic value similar to that of liver biopsy.