Impact of the New Definition of Metabolic Associated Fatty Liver Disease on the Epidemiology of the Disease

BACKGROUND & AIMS

Recently, a group of hepatologists proposed to rename non-alcoholic fatty liver disease (NAFLD) as metabolic associated fatty liver disease (MAFLD) with modified diagnostic criteria. We aimed to study the impact of the new definition on the epidemiology of fatty liver disease.

METHODS

We randomly selected 1013 adults from the Hong Kong census database for clinical assessment, proton-magnetic resonance spectroscopy, and transient elastography. Five hundred sixty-five subjects without fatty liver at baseline underwent follow-up assessment. MAFLD was diagnosed as intrahepatic triglyceride content (IHTG) ≥5% and the presence of overweight/obesity, diabetes, or two other metabolic risk factors, with and without concomitant liver diseases. The diagnosis of NAFLD required the exclusion of concomitant liver diseases; metabolic factors were not considered.

RESULTS

The population prevalence of MAFLD and NAFLD was 25.9% (95% CI 23.2-28.7%) and 25.7% (95% CI 23.1-28.5%), respectively. Among 277 subjects with IHTG ≥5%, 247 (89.2%) fulfilled both the definitions of MAFLD and NAFLD. Fourteen subjects (5.1%) had IHTG ≥5% but did not meet the metabolic criteria of MAFLD. The incidence of MAFLD was 2.8 per 100 person-years at a median interval of 47 months (range 34-60 months). Among 78 subjects with incident NAFLD, 59 (75.6%) met the criteria of MAFLD; only one of the latter, a regular drinker, had liver stiffness ≥10 kPa.

CONCLUSIONS

The new definition of MAFLD does not significantly change the prevalence compared with NAFLD, but it may reduce the incidence by 25%. People with hepatic steatosis but not fulfilling the definition of MAFLD unlikely have significant liver disease.

Serial Transient Elastography Examinations to Monitor Patients With Type 2 Diabetes: A Prospective Cohort Study

BACKGROUND AND AIMS

Type 2 diabetes is an important risk factor for nonalcoholic fatty liver disease (NAFLD) and advanced fibrosis. Current international guidelines recommend the use of noninvasive tests as initial assessments for NAFLD, but the role of noninvasive tests as monitoring tools has not been established. We aimed to study the role of transient elastography as a monitoring tool in patients with type 2 diabetes.

APPROACH AND RESULTS

We recruited patients with type 2 diabetes without viral hepatitis or excessive alcohol intake from a complication screening facility in Hong Kong in 2013-2014 and repeated the assessments in 2016-2018. The primary endpoint was an increase of liver stiffness measurement (LSM) to ≥10 kPa. The secondary endpoint was the change in the controlled attenuation parameter (CAP). A total of 611 patients with type 2 diabetes and a valid LSM (mean age, 57.7 ± 10.9 years; 342 men [56.0%]) were included in this study (568 also had a valid CAP). Overall, there was moderate correlation between the baseline and follow-up LSM (r = 0.689, P < 0.001). Among 487 patients with a baseline LSM <10 kPa, 21 (4.3%) had a follow-up LSM ≥10 kPa. Baseline body mass index, alanine aminotransferase (ALT), and ∆ALT were independent factors associated with LSM increase. Among 124 patients with a baseline LSM ≥10 kPa, 70 (56.5%) had a follow-up LSM <10 kPa. Among 198 patients with a CAP <248 dB/m at baseline, 103 (52.0%) had a CAP increased to ≥248 dB/m.

CONCLUSIONS

The prevalence and incidence of NAFLD in patients with type 2 diabetes are high. Although advanced fibrosis is common in this population, few patients progress to advanced fibrosis in 3 years. Future studies should define the optimal surveillance interval in patients with diabetes.

Modelling the economic and clinical burden of non-alcoholic steatohepatitis in East Asia: Data from Hong Kong

AIM

Non-alcoholic steatohepatitis (NASH) is the progressive form of non-alcoholic fatty liver disease (NAFLD) and prevalence is rising in Asia due to increasing rates of urbanization, sedentary lifestyles, and poor nutrition.

METHODS

We built a Markov model with 20-year horizon to estimate the burden of NASH in Hong Kong. Cohort size was determined by population size, prevalence of NAFLD, and incidence of NASH in 2017. Health states include hepatic steatosis, fibrosis stages 0-3, compensated and decompensated cirrhosis, hepatocellular carcinoma, post-liver transplant, and liver-related, cardiovascular, and background mortality. Transition probabilities were estimated from published reports and we converted 2017 Gazette price from the Hospital Authority of Hong Kong to US dollars. We discounted costs by 3% annually. Health utilities were assumed to be the same as in the USA.

RESULTS

Non-alcoholic steatohepatitis will cost $1.32 billion and 124 liver transplants over 20 years, with average cost per person-year of $257. Sensitivity analyses show our model is robust in predicting costs for the prevalent population but likely overestimates costs for the incident population.

CONCLUSIONS

Non-alcoholic steatohepatitis will contribute to a significant clinical and economic burden in Hong Kong over the next two decades. Due to the limited number of donors and small number of liver transplants undertaken annually, patients with advanced liver disease due to NASH in Hong Kong are more likely to die from NASH than their counterparts in North America and Europe. Thus, rising prevalence of metabolic syndrome in elderly adults in Hong Kong make NASH an important consideration for clinicians and policy makers.

Quantifying and monitoring fibrosis in non-alcoholic fatty liver disease using dual-photon microscopy

OBJECTIVE

Fibrosis stage is strongly associated with liver-related outcomes and is a key surrogate endpoint in drug trials for non-alcoholic steatohepatitis. Dual-photon microscopy allows automated quantification of fibrosis-related parameters (q-FPs) and may facilitate large-scale histological studies. We aim to validate the performance of q-FPs in a large histological cohort.

DESIGN

344 patients with non-alcoholic fatty liver disease (NAFLD) underwent 428 liver biopsies (240 had paired transient elastography examination). Fibrosis stage was scored using the NASH Clinical Research Network system, and q-FPs were measured by dual-photon microscopy using unstained slides. Patients were randomly assigned to the training and validation cohorts to test the performance of individual q-FPs and derive optimal cut-offs.

RESULTS

Over 25 q-FPs had area under the receiver-operating characteristics curves >0.90 for different fibrosis stages. Among them, the perimeter of collagen fibres and number of long collagen fibres had the highest accuracy. At the best cut-offs, the two q-FPs had 88.3%-96.2% sensitivity and 78.1%-91.1% specificity for different fibrosis stages in the validation cohort. q-FPs and histological scoring had nearly identical correlations with liver stiffness measurement, suggesting that the accuracy of q-FPs approached that of histological assessment. Among patients with paired liver biopsies, changes in the same q-FPs were associated with changes in fibrosis stage. At a median follow-up of 5.6 years, baseline q-FPs predicted liver-related events.

CONCLUSION

q-FP is highly accurate in the assessment of fibrosis in NAFLD patients. This automated platform can be used in future studies as objective and reliable evaluation of histological fibrosis.

Liver stiffness measurement predicts long-term survival and complications in non-alcoholic fatty liver disease

BACKGROUND AND AIMS

In non-alcoholic fatty liver disease (NAFLD), fibrosis is the strongest prognostic factor and can be assessed by non-invasive methods. We evaluated the ability of liver stiffness measurement (LSM) to predict overall survival and liver, cardiovascular and oncologic complications.

METHODS

We prospectively collected data on 2251 consecutive NAFLD patients (mean age 59 years, male 53%, mean body mass index 28 kg/m² ) in two centres. At inclusion, all patients had LSM, clinical and biological evaluation. During follow-up, we recorded cardiovascular events, cancers, liver complications, liver transplantation and death. The primary endpoint was overall survival. Survival curves according to LSM were first performed using Kaplan-Meier method for the primary endpoint, and Aalen-Johansen method for secondary outcomes to take into account competitive risks. In a second step, a Cox proportional hazard model analysis was done to identify independent predictors of overall survival.

RESULTS

Median follow-up was 27 months [IQR: 25-38]. Fifty-five patients died and three patients had liver transplantation. Overall survival significantly decreased as baseline LSM increased. Twenty-one patients (0.9%) had a liver event, 142 (6.3%) developed cancer (excluding HCC) and 151 (6.7%) had a cardiovascular event during follow-up. By multivariable analysis, independent predictors of overall survival were as follows: baseline LSM (adjusted HR (aHR) = 2.85 [1.65-4.92], P = .0002), age (aHR = 1.11 [1.08-1.13], P < .0001) and male sex (aHR = 2.05 [1.17-3.57], P = .012). Patients with elevated LSM were also more likely to develop cardiovascular, and liver events but not other cancers.

CONCLUSION

LSM can be used to predict survival, cardiovascular and liver complications in NAFLD patients.

Unified interpretation of liver stiffness measurement by M and XL probes in non-alcoholic fatty liver disease

OBJECTIVE

The latest model of vibration-controlled transient elastography (VCTE) automatically selects M or XL probe according to patients' body built. We aim to test the application of a unified interpretation of VCTE results with probes appropriate for the body mass index (BMI) and hypothesise that this approach is not affected by hepatic steatosis.

DESIGN

We prospectively recruited 496 patients with non-alcoholic fatty liver disease who underwent VCTE by both M and XL probes within 1 week before liver biopsy.

RESULTS

391 (78.8%) and 433 (87.3%) patients had reliable liver stiffness measurement (LSM) (10 successful acquisitions and IQR:median ratio ≤0.30) by M and XL probes, respectively (p<0.001). The area under the receiver operating characteristic curves was similar between the two probes (0.75-0.88 for F2-4, 0.83-0.91 for F4). When used in the same patient, LSM by XL probe was lower than that by M probe (mean difference 2.3 kPa). In contrast, patients with BMI ≥30 kg/m² had higher LSM regardless of the probe used. When M and XL probes were used in patients with BMI <30 and ≥30 kg/m², respectively, they yielded nearly identical median LSM at each fibrosis stage and similar diagnostic performance. Severe steatosis did not increase LSM or the rate of false-positive diagnosis by XL probe.

CONCLUSION

High BMI but not severe steatosis increases LSM. The same LSM cut-offs can be used without further adjustment for steatosis when M and XL probes are used according to the appropriate BMI.

Repeating measurements by transient elastography in non-alcoholic fatty liver disease patients with high liver stiffness

BACKGROUND AND AIM

The Baveno VI Consensus recommends repeating examination in patients with high liver stiffness measurement (LSM) by transient elastography to reduce false-positive diagnosis of advanced liver disease. We tested whether repeating transient elastography can increase the overall diagnostic accuracy.

METHODS

Ninety-seven patients with non-alcoholic fatty liver disease who underwent two FibroScan examinations within 6 months prior to liver biopsy were evaluated. An LSM cut-off of 7.9 kPa was used to exclude F3-4 fibrosis.

RESULTS

Seventy-eight patients had high LSM at baseline, among whom 27 had low LSM on repeated testing; only four had F3 and none had cirrhosis. In contrast, 31 of 51 patients with high LSM at both examinations had F3-4. Nineteen patients had low LSM at baseline; none of them had F3-4 regardless of the second LSM results. If we took LSM <7.9 kPa at either examination as sufficient to exclude F3-4, the negative predictive value remained high at 91%. The positive predictive value for F3-4 increased from 45% in patients with high LSM at baseline to 61% in those with high LSM at both examinations. Sensitivity analysis using different cut-offs yielded similar results, with 76% of patients with LSM >12 kPa at both examinations having F3-4.

CONCLUSIONS

Transient elastography is a highly sensitive screening test to exclude F3-4 fibrosis in non-alcoholic fatty liver disease patients. One-third of patients with high LSM may have normal results on repeated examination. By repeating examination in cases with high LSM, one may spare patients from unnecessary liver biopsy.

Advanced liver fibrosis but not steatosis is independently associated with albuminuria in Chinese patients with type 2 diabetes

BACKGROUND & AIMS

Increasing evidence suggests that non-alcoholic fatty liver disease (NAFLD) may be an independent risk factor for chronic kidney disease (CKD). Given the high prevalence of NAFLD among patients with diabetes who are also at risk of CKD, we aimed to investigate the association between NAFLD and albuminuria, a marker commonly found in diabetic nephropathy.

METHODS

This study included a cohort of Chinese patients with type 2 diabetes from the Hong Kong Diabetes Registry recruited between March 2013 and May 2014. Liver stiffness measurement (LSM), with probe-specific cut-offs, was used to detect advanced liver fibrosis. While controlled attenuation parameter (CAP) was used to assess liver steatosis using transient elastography.

RESULTS

A total of 1,763 Chinese patients with type 2 diabetes were recruited in this analysis. The mean (standard deviation) age and duration of diabetes were 60.7 (11.5) years and 10.8 (8.5) years, respectively. The prevalence of albuminuria was higher in diabetic patients with liver steatosis and those with advanced fibrosis (no NAFLD vs. liver steatosis vs. advanced fibrosis: 41.4% vs. 46.2% vs. 64.2%, p <0.001). After adjustment for potential confounders including glycated hemoglobin, hypertension and body mass index, advanced fibrosis, but not liver steatosis, was associated with increased risk of albuminuria (odds ratio [OR] 1.52; 95% confidence interval [CI] 1.02-2.28; p = 0.039) in patients with eGFR ≥60 ml/min/1.73 m2. The odds of albuminuria increased with greater severity of liver fibrosis in a dose dependent manner, with the highest odds observed in patients with LSM scores ≥11.5 kPa assessed by M probe or ≥11.0 kPa assessed by XL probe (adjusted OR 1.53; 95% CI 1.07-2.20; p = 0.021).

CONCLUSIONS

Advanced liver fibrosis, but not steatosis, is independently associated with albuminuria in Chinese patients with type 2 diabetes. Attention should be paid to liver fibrosis in patients with obesity and type 2 diabetes complicated with albuminuria.

LAY SUMMARY

In this study, we assessed the link between non-alcoholic fatty liver disease (NAFLD) and albuminuria in a cohort of 1,763 Chinese patients with type 2 diabetes. This study shows that advanced liver fibrosis, a severe form of NAFLD, was independently associated with increased risk of albuminuria. The risk of albuminuria increased with greater severity of liver fibrosis.

Application of the combined FibroMeter vibration-controlled transient elastography algorithm in Chinese patients with non-alcoholic fatty liver disease

BACKGROUND AND AIM

The FibroMeter vibration-controlled transient elastography (FM VCTE) is a new formula combining the serum test FM and liver stiffness measurement (LSM) by VCTE. We tested the accuracy and utility of FM VCTE for fibrosis staging in patients with non-alcoholic fatty liver disease (NAFLD).

METHODS

Two hundred fifteen NAFLD patients with LSM, FM NAFLD, FM VCTE, and other serum tests (aspartate aminotransferase-to-platelet ratio index, fibrosis-4 index, BARD score, NAFLD fibrosis score, and aspartate aminotransferase-to-alanine aminotransferase ratio) performed 1 day before liver biopsy were evaluated.

RESULTS

Sixty-nine (32.1%) and 43 (20.0%) patients had F2-4 and F3-4, respectively. LSM had higher diagnostic accuracy (area under receiver-operating characteristics curves [AUROC] 0.851 for F2-4, 0.940 for F3-4; Obuchowski index 0.937 ± 0.007) than all evaluated serum tests, while FM NAFLD was the most accurate serum test (AUROC 0.775 and 0.774; Obuchowski index 0.891 ± 0.013). FM VCTE had similar accuracy to LSM (AUROC 0.855 and 0.901; Obuchowski index 0.927 ± 0.009). LSM had excellent negative predictive values of 92.4% and 99.2% to exclude F2-4 and F3-4, but the positive predictive values (PPV) were only 71.4% and 61.0%, respectively. In patients with high LSM, the use of FM VCTE improved the PPV from 71.4% to 84.4% for F2-4 and from 61.0% to 88.9% for F3-4. Liver biopsy could be spared in around 50-65% of patients.

CONCLUSIONS

Liver stiffness measurement alone can confidently exclude significant and advanced fibrosis in NAFLD patients. Using FM VCTE in patients with high liver stiffness can increase the positive predictive value to rule in F2-4 and F3-4.

Histological severity and clinical outcomes of nonalcoholic fatty liver disease in nonobese patients

Although nonalcoholic fatty liver disease (NAFLD) is closely linked to obesity, around 10%-20% of nonobese Americans and Asians still develop NAFLD. Data on this special group are limited. We therefore studied the severity and clinical outcomes of nonobese NAFLD patients. Consecutive NAFLD patients who underwent liver biopsy were prospectively recruited. We used the NASH Clinical Research Network system to score the histology. The Asian body mass index cutoff of 25 kg/m² was used to define nonobese NAFLD. Among 307 recruited NAFLD patients, 72 (23.5%) were nonobese. Compared to obese patients, nonobese patients had lower NAFLD activity score (3.3 ± 1.3 vs. 3.8 ± 1.2; P = 0.019), mainly contributed by steatosis (1.7 ± 0.8 vs. 2.0 ± 0.8; P = 0.014) and presence of hepatocyte ballooning (60.9% vs. 73.4%; P = 0.045). Similarly, nonobese patients had lower fibrosis stage (1.3 ± 1.5 vs. 1.7 ± 1.4; P = 0.004), serum cytokeratin-18 fragments (283 vs. 404 U/L; P < 0.001) and liver stiffness measurement by transient elastography (6.3 vs. 8.6 kilopascals; P < 0.001). By multivariate analysis in nonobese patients, only elevated serum triglyceride level was independently associated with higher NAFLD activity score (adjusted odds ratio [OR], 1.644; P = 0.021), whereas elevated creatinine level was the only factor associated with advanced fibrosis (adjusted OR, 1.044; P = 0.025). After a median follow-up of 49 months, 6 patients died, 2 developed hepatocellular carcinoma, and 1 had liver failure, all of whom were in the obese group.

CONCLUSION

Nonobese NAFLD patients tend to have less-severe disease and may have a better prognosis than obese patients. Hypertriglyceridemia and higher creatinine are the key factors associated with advanced liver disease in nonobese patients. (Hepatology 2017;65:54-64).

Screening diabetic patients for non-alcoholic fatty liver disease with controlled attenuation parameter and liver stiffness measurements: a prospective cohort study

OBJECTIVE

Type 2 diabetes is an important risk factor for non-alcoholic fatty liver disease (NAFLD), but current guidelines provide conflicting recommendations on whether diabetic patients should be screened for NAFLD. We therefore studied the strategy of screening diabetic patients by FibroScan.

DESIGN

Liver fat and fibrosis were assessed by controlled attenuation parameter (CAP) and liver stiffness measurements (LSM) by FibroScan at a diabetic centre for patients from primary care and hospital clinics. Probe-specific LSM cut-offs were used to detect advanced fibrosis.

RESULTS

Of 1918 patients examined, 1799 (93.8%) had valid CAP and 1884 (98.2%) had reliable LSM (1770 with the M probe and 114 with the XL probe). The proportion of patients with increased CAP and LSM was 72.8% (95% CI 70.7% to 74.8%) and 17.7% (95% CI 16.0% to 19.5%), respectively. By multivariable analysis, female gender, higher body mass index, triglycerides, fasting plasma glucose and alanine aminotransferase (ALT) and non-insulin use were associated with increased CAP. Longer duration of diabetes, higher body mass index, increased ALT and spot urine albumin:creatinine ratio and lower high-density lipoprotein-cholesterol were associated with increased LSM. Ninety-four patients (80% had increased LSM) underwent liver biopsy: 56% had steatohepatitis and 50% had F3-4 disease.

CONCLUSIONS

Diabetic patients have a high prevalence of NAFLD and advanced fibrosis. Those with obesity and dyslipidaemia are at particularly high risk and may be the target for liver assessment. Our data support screening for NAFLD and/or advanced fibrosis in patients with type 2 diabetes.