Evaluation of the nonalcoholic fat liver disease fibrosis score for patients undergoing bariatric surgery

Accuracy of prognostic serological biomarkers in predicting liver fibrosis severity in people with metabolic dysfunction-associated steatotic liver disease: a meta-analysis of over 40,000 participants

Introduction

A prognostic model to predict liver severity in people with metabolic dysfunction-associated steatotic liver disease (MASLD) is very important, but the accuracy of the most commonly used tools is not yet well established.

Objective

The meta-analysis aimed to assess the accuracy of different prognostic serological biomarkers in predicting liver fibrosis severity in people with MASLD.

Methods

Adults ≥18 years of age with MASLD were included, with the following: liver biopsy and aspartate aminotransferase-to-platelet ratio (APRI), fibrosis index-4 (FIB-4), non-alcoholic fatty liver disease fibrosis score (NFS), body mass index, aspartate aminotransferase/alanine aminotransferase ratio, diabetes score (BARD score), FibroMeter, FibroTest, enhanced liver fibrosis (ELF), Forns score, and Hepascore. Meta-analyses were performed using a random effects model based on the DerSimonian and Laird methods. The study's risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2.

Results

In total, 138 articles were included, of which 86 studies with 46,514 participants met the criteria for the meta-analysis. The results for the summary area under the receiver operating characteristic (sAUROC) curve, according to the prognostic models, were as follows: APRI: advanced fibrosis (AF): 0.78, any fibrosis (AnF): 0.76, significant fibrosis (SF): 0.76, cirrhosis: 0.72; FIB-4: cirrhosis: 0.83, AF: 0.81, AnF: 0.77, SF: 0.75; NFS: SF: 0.81, AF: 0.81, AnF: 0.71, cirrhosis: 0.69; BARD score: SF: 0.77, AF: 0.73; FibroMeter: SF: 0.88, AF: 0.84; FibroTest: SF: 0.86, AF: 0.78; and ELF: AF: 0.87.

Conclusion

The results of this meta-analysis suggest that, when comparing the scores of serological biomarkers with liver biopsies, the following models showed better diagnostic accuracy in predicting liver fibrosis severity in people with MASLD: FIB-4 for any fibrosis, FibroMeter for significant fibrosis, ELF for advanced fibrosis, and FIB-4 for cirrhosis.Clinical trial registration: [https://clinicaltrials.gov/], identifier [CRD 42020180525].

The Use of Noninvasive Scores in Predicting NAFLD Progression After Bariatric Surgery

BACKGROUND

Bariatric surgery has been postulated to impact liver function resulting in favorable effects on nonalcoholic fatty liver disease (NAFLD). We aimed to analyze the long-term impact of bariatric surgery on noninvasive scores predicting the progression of liver fibrosis in a bariatric population.

METHODS

We retrospectively reviewed the records of patients without pre-existing liver disease who underwent sleeve gastrectomy or Roux-en-Y gastric bypass (RYGB) at our center between 2010 and 2018. Four predictive scores for liver fibrosis (AST/ALT, APRI, Fib-4, and BARD) were calculated preoperatively, 6 months post-operatively, and annually up to 5 years. Correlations were analyzed with Pearson R. Subgroup and sensitivity analyses were performed to identify populations at increased risk.

RESULTS

A total of 2769 patients were included. The mean age was 40 years, and the majority was females (88.5%) and of Hispanic ethnicity (59.2%). There was a steady post-operative increase in the percentage of patients at increased risk of progression of liver fibrosis. The Fib-4 score showed the largest increase in the population at risk for liver fibrosis (11.3% preoperatively to 28.9% at 5 years). Patients with diabetes and those who underwent a sleeve gastrectomy continued to display a higher risk for liver fibrosis than did patients without diabetes and those who underwent RYGB, respectively.

CONCLUSION

There was an overall trend to increased liver fibrosis scores over the 5-year post-operative follow-up, but this increase remained lower than that reported in previous literature. Bariatric surgery offers NAFLD risk reduction in a high-risk population.

Obesity Modifies the Performance of Fibrosis Biomarkers in Nonalcoholic Fatty Liver Disease

CONTEXT

Guidelines recommend blood-based fibrosis biomarkers to identify advanced nonalcoholic fatty liver disease (NAFLD), which is particularly prevalent in patients with obesity.

OBJECTIVE

To study whether the degree of obesity affects the performance of liver fibrosis biomarkers in NAFLD.

DESIGN

Cross-sectional cohort study comparing simple fibrosis scores [Fibrosis-4 Index (FIB-4); NAFLD Fibrosis Score (NFS); aspartate aminotransferase to platelet ratio index; BARD (body mass index, aspartate-to-alanine aminotransferase ratio, diabetes); Hepamet Fibrosis Score (HFS)] and newer scores incorporating neo-epitope biomarkers PRO-C3 (ADAPT, FIBC3) or cytokeratin 18 (MACK-3).

SETTING

Tertiary referral center.

PATIENTS

We recruited overweight/obese patients from endocrinology (n = 307) and hepatology (n = 71) clinics undergoing a liver biopsy [median body mass index (BMI) 40.3 (interquartile range 36.0-44.7) kg/m2]. Additionally, we studied 859 less obese patients with biopsy-proven NAFLD to derive BMI-adjusted cutoffs for NFS.

MAIN OUTCOME MEASURES

Biomarker area under the receiver operating characteristic (AUROC), sensitivity, specificity, and predictive values to identify histological stage ≥F3 fibrosis or nonalcoholic steatohepatitis with ≥F2 fibrosis [fibrotic nonalcoholic steatohepatitis (NASH)].

RESULTS

The scores with an AUROC ≥0.85 to identify ≥F3 fibrosis were ADAPT, FIB-4, FIBC3, and HFS. For fibrotic NASH, the best predictors were MACK-3 and ADAPT. The specificities of NFS, BARD, and FIBC3 deteriorated as a function of BMI. We derived and validated new cutoffs for NFS to rule in/out ≥F3 fibrosis in groups with BMIs <30.0, 30.0 to 39.9, and ≥40.0 kg/m2. This optimized its performance at all levels of BMI. Sequentially combining FIB-4 with ADAPT or FIBC3 increased specificity to diagnose ≥F3 fibrosis.

CONCLUSIONS

In obese patients, the best-performing fibrosis biomarkers are ADAPT and the inexpensive FIB-4, which are unaffected by BMI. The widely used NFS loses specificity in obese individuals, which may be corrected with BMI-adjusted cutoffs.

TGF-β1 signaling can worsen NAFLD with liver fibrosis backdrop

Non-Alcoholic Fatty Liver Disease (NAFLD) is characterized by the accumulation of fats in the liver. Relatively benign NAFLD often progresses to fibrosis, cirrhosis, and liver malignancies. Although NAFLD precedes fibrosis, continuous lipid overload keeps fueling fibrosis and the process of disease progression remains unhindered. It is well known that TGF-β1 plays its part in liver fibrosis, yet its effects on liver lipid overload remain unknown. As TGF-β1 signaling has been increasingly attempted to manage liver fibrosis, its actions on the primary suspect (NAFLD) are easily ignored. The complex interaction of inflammatory stress and lipid accumulation aided by mediators scuh as pro-inflammatory interleukins and TGF-β1 forms the basis of NAFLD progression. Anticipatorily, the inhibition of TGF-β1 signaling during anti-fibrotic treatment should reverse the NAFLD though the data remain scattered on this subject to date. TGF-β1 signaling pathway is an important drug target in liver fibrosis and abundant literature is available on it, but its direct effects on NAFLD are rarely studied. This review aims to cover the pathogenesis of NAFLD focusing on the role of the TGF-β1 in the disease progression, especially in the backdrop of liver fibrosis.

Bariatric surgery improves metabolic and nonalcoholic fatty liver disease markers in metabolically healthy patients with morbid obesity at 5 years

BACKGROUND

No studies have evaluated the effect of metabolic and bariatric surgery (MBS) on nonalcoholic fatty liver disease (NAFLD) and cardiometabolic markers in metabolically healthy patients with morbid obesity (MHMO) at midterm.

OBJECTIVES

To assess the effect of MBS on NAFLD and cardiometabolic markers in MHMO patients and ascertain whether metabolically unhealthy patients with morbid obesity (MUMO) remain metabolically healthy at 5 years after MBS.

SETTING

University hospital.

METHODS

A total of 191 patients with a body mass index >40 kg/m² and at least 5 years of follow-up were retrospectively analyzed. Lost to follow-up were 37.6% (151 of 401 patients). Patients were classified as MHMO if 1 or 0 of the cardiometabolic markers were present using the Wildman criteria. The degree of liver fibrosis was assessed using the NAFLD fibrosis score (NFS).

RESULTS

Forty-one patients (21.5%) fulfilled the criteria for MHMO. They showed significant improvements in blood pressure (from 135.1 ± 22.1 and 84.2 ± 14.3 mm Hg to 117.7 ± 19.2 and 73.0 ± 10.9 mm Hg), plasma glucose (from 91.0 ± 5.6 mg/dL to 87.2 ± 5.2 mg/dL), homeostatic model assessment for insulin resistance (from 2.2 ± .9 to 1.0 ± .8), triglycerides (from 88.0 [range, 79.5-103.5] mg/dL to 61.0 [range, 2.0-76.5] mg/dL), alanine aminotransferase, gamma-glutamyl transpeptidase NFS (from -1.0 ± 1.0 to -1.9 ± 1.2), and high-density lipoprotein cholesterol (from 56.9 ± 10.5 mg/dL to 77.9 ± 17.4 mg/dL) at 5 years after surgery. A total of 108 MUMO patients (84.4%) who became metabolically healthy after 1 year stayed healthy at 5 years.

CONCLUSIONS

MBS induced a midterm improvement in cardiometabolic and NAFLD markers in MHMO patients. Seventy-six percent of MUMO patients became metabolically healthy at 5 years after MBS.

Differential Outcomes and Clinical Challenges of NAFLD With Extreme Obesity

Nonalcoholic fatty liver disease (NAFLD) is closely associated with obesity. The prevalence of extreme obesity, defined as body mass index (BMI) of 50 kg/m² or higher, is rising more rapidly than overall obesity. We aimed to compare the clinical outcomes and performance of noninvasive fibrosis assessment tools in NAFLD with or without extreme obesity. A retrospective analysis was performed in 304 patients with NAFLD with extreme obesity and compared them to patients with NAFLD with BMI of 40 kg/m² or less, matched for age, gender, race, and liver fibrosis stage. The mean age of the NAFLD with extreme obesity cohort was 55.9 years, BMI 55 kg/m², and 49.7% had cirrhosis at initial evaluation. Baseline cirrhosis and coronary artery disease were associated with increased risk of death, and dyslipidemia with decreased risk of mortality. Age, insulin use, hypertension, albumin and platelet count were associated with cirrhosis. Fifteen percent of patients had weight‐loss surgery, but this was not associated with survival or risk of cirrhosis. Of the 850 abdominal ultrasound scans performed in 255 patients, 24.1% were deemed suboptimal for hepatocellular carcinoma screening. The mean NAFLD fibrosis score (NFS) in the extreme obesity cohort, versus a propensity‐matched cohort with BMI of 40 kg/m² or less, was significantly different for both low fibrosis (F0‐F2) (0.222 vs. −1.682, P < 0.0001) and high fibrosis (F3‐F4) (2.216 vs. 0.557, P < 0.001). Conclusion: NAFLD with extreme obesity is associated with increased risk of liver‐related and overall mortality. Accurate noninvasive assessment of liver fibrosis, low rates of weight loss surgery, and high failure rate of ultrasound were identified as clinical challenges in this population.

Improvement in Non-alcoholic Fatty Liver Disease Score Correlates with Weight Loss in Obese Patients Undergoing Laparoscopic Sleeve Gastrectomy: a Two-Centre Study from an Asian Cohort

PURPOSE

Incidence of non-alcoholic fatty liver disease (NAFLD) is on the rise and is one of the most common causes of chronic liver disease worldwide. Obesity and metabolic syndrome are considered the most significant risk factors. Bariatric surgery is the only treatment modality in morbid obesity which allows long-term weight loss with improvement in associated co-morbid conditions. However, the effects of bariatric surgery on NAFLD are not well established. NAFLD fibrosis score (NFS) is a validated non-invasive scoring system used to assess advanced fibrosis. We used the NFS to analyse the impact of weight loss on NAFLD following sleeve gastrectomy.

MATERIALS AND METHODS

174 patients who underwent bariatric surgery between 2010 and 2016 were retrospectively reviewed. Multivariate analysis was performed using pre-operative patient characteristics, biochemical markers and TANITA body analysis measurements to determine significant risk factors for NFS > 0.675. Additionally, the NFS was calculated at 6 months, 1 year and 2 years post-operatively to determine correlation with weight loss.

RESULTS

Pre-operatively, 13.8% of our patients had significant fibrosis by NFS. Mean change in NFS was - 0.46 ± 1.02, - 0.55 ± 0.98 and - 0.55 ± 1.12 at 6 months, 1 year and 2 years respectively. This was significantly correlated with percent of total weight loss with R coefficients of 0.253, 0.292 and 0.274 respectively (P < 0.05). 79.2% of patients with NFS > 0.675 achieved resolution by 2 years post-operatively.

CONCLUSION

Based on our study, we conclude that sleeve gastrectomy may be a viable treatment option for management of NAFLD in the obese.

Performance of noninvasive scores for the diagnosis of advanced liver fibrosis in morbidly obese with nonalcoholic fatty liver disease

OBJECTIVES

Liver fibrosis is one of the most important predictors of mortality related to nonalcoholic fatty liver disease (NAFLD). The use of noninvasive markers has the advantage of a simple and low-cost evaluation. The aim of this study was to evaluate the performance of six noninvasive scores for the diagnosis of advanced liver fibrosis in morbidly obese patients.

MATERIAL AND METHODS

A retrospective study validation included 323 morbidly obese patients undergoing bariatric surgery. Advance fibrosis was defined as stage 3 and 4 (septal fibrosis or cirrhosis). Accuracy, sensitivity, specificity, positive (PPV) or negative (NPV) predictive value, and positive (PLR) or negative (NLR) likelihood ratio test of the following noninvasive liver fibrosis scores were evaluated: aspartate aminotransferase (AST)/alanine aminotransferase (ALT) ratio (AAR); AST to platelet ratio index (APRI); BARD; FIB4, NAFLD fibrosis score (NFS) and BAAT, which were compared with the histological findings of the intraoperative liver biopsy. The cutoff points established in the validation studies were used: AAR  >  1; APRL  >  0.98; BARD  ≥  2; FIB4  >  2.67; NFS  >  0.676 and BAAT  >  1.

RESULTS

Twenty-nine patients (8.97%) presented advanced fibrosis. APRI presented the higher specificity (99.61%), PPV (85.71%), PLR (62.5) and accuracy (0.93). FIB4 was the second test in accuracy (0.9) and in PLR (10.53). BAAT presented the highest sensitivity (73.08%) and NPV (94.78%); NFS the lowest sensitivity (12,5%), and BARD the lowest accuracy (0.44).

CONCLUSION

APRI and FIB-4 were the tests with best performance to predict advanced fibrosis.

Systematic review and meta-analysis: non-invasive detection of non-alcoholic fatty liver disease related fibrosis in the obese

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) is a significant disease burden in obesity. Liver fibrosis is an important prognostic factor in NAFLD, and detection is vital. The pathophysiological changes of obesity can alter the accuracy of non-invasive NAFLD tests. We aimed to review current evidence for common non-invasive tests for NAFLD-related fibrosis in obesity.

METHODS

We systematically searched for studies assessing the diagnostic accuracy of 11 biomarker panels and elastography techniques for NAFLD-related fibrosis in obesity. Meta-analyses were performed where possible.

RESULTS

Thirty-eight studies were identified assessing the selected tests in obese populations. Simple biomarker panels (e.g. NAFLD fibrosis score) were the most validated. Evidence showed better accuracy of complex biomarker panels (NAFLD fibrosis score: summary receiver operator characteristic [SROC] 0.795-0.813 vs. enhanced liver fibrosis: SROC 0.962); however, these were poorly validated in obesity. Elastography techniques were better studied and had high diagnostic accuracy (transient elastography: SROC 0.859; magnetic resonance elastography: SROC 0.965) but were limited by BMI-dependent failure. Limited evidence was found to validate the accuracy of any test in exclusively obese populations.

CONCLUSION

In obese subjects, complex biomarker panels and elastography have been reasonable to good accuracy for NAFLD-related fibrosis; however, these methods have not been well validated. Further study in this high-risk population is needed.

COMPARISON OF HEPATIC PROFILE IN PRE AND POSTOPERATIVE OF BARIATRIC SURGERY: PRIVATE VS PUBLIC NETWORK

Background:

Obesity is associated to several comorbidities, including nonalcoholic fatty liver disease, which implicates in isolated steatosis to steatohepatitis. The latter may progress to severe manifestations such as liver fibrosis, cirrhosis and hepatocellular carcinoma.

Aim:

To compare the presence of advanced liver fibrosis before and after bariatric surgery in patients of private and public health system.

Methods:

Patients from public and privative networks were studied before and after bariatric surgery. The presence or absence of advanced hepatic fibrosis was evaluated by NAFLD Fibrosis Score, a non-invasive method that uses age, BMI, AST/ALT ratio, albumin, platelet count and the presence or absence of hyperglycemia or diabetes. The characteristics of the two groups were compared. The established statistical significance criterion was p<0.05.

Results:

Were analyzed 40 patients with a mean age of 34.6±9.5 years for private network and 40.6± 10.2 years for public. The study sample, 35% were treated at private health system and 65% in the public ones, 38% male and 62% female. Preoperatively in the private network one (7.1%) patient had advanced liver fibrosis and developed to the absence of liver fibrosis after surgery. In the public eight (30.8%) patients had advanced liver fibrosis preoperatively, and at one year after the proportion fell to six (23%).

Conclusion:

The non-alcoholic fatty liver disease in its advanced form is more prevalent in obese patients treated in the public network than in the treated at the private network and bariatric surgery may be important therapeutic option in both populations.

Role of the gastroenterologist in the management of the obese patient

Obesity is a highly prevalent disease worldwide, and one in which gastroenterologists can play an important role. Some digestive diseases are more common in obese patients, and preoperative evaluation may be required in some cases. Additionally, bariatric surgery can lead to digestive complications in the short and long term that require intervention, and endoscopic treatment can be an important factor in weight loss. The aim of this review is to highlight the role of the gastroenterologist in the management of obese patients who are either scheduled for or have undergone surgical or endoscopic treatment for obesity.

Influence of type 2 diabetes mellitus on liver histology among morbidly obese individuals. A cross-sectional study

CONTEXT AND OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) has become a public health concern. It encompasses a wide spectrum of histological abnormalities and has close relationships with insulin resistance and type 2 diabetes mellitus (T2DM). This study sought to compare the histological alterations observed in morbidly obese individuals with and without T2DM who underwent Roux-en-Y gastric bypass.

DESIGN AND SETTING

Cross-sectional study in a tertiary-level public hospital.

METHODS

This was a cross-sectional study on 197 individuals who underwent gastric bypass surgery between 2011 and 2013. NAFLD was assessed through liver biopsies. T2DM was diagnosed through the International Diabetes Federation criteria.

RESULTS

Non-diabetics presented significantly more biopsies without any histological abnormalities, regarding steatosis (42.6% versus 25.5%; P = 0.0400), fibrosis (60.6% versus 36.2%; P = 0.0042) and steatohepatitis (27.3% versus 12.8%; P = 0.0495), while diabetics presented significantly higher frequency of moderate forms of steatosis (36.2% versus 20%; P = 0.0307) and fibrosis (23.4% versus 4%; P = 0.0002).

DISCUSSION

T2DM was associated with more advanced forms of NAFLD within the population studied. NAFLD has previously been correlated with severe forms of heart disease.

CONCLUSION

Screening for and early detecting of NAFLD in high-risk populations are important for avoiding further development of severe forms and the need for liver transplantation.

Effect of Roux-en-Y gastric bypass on nonalcoholic fatty liver disease evaluated through NAFLD fibrosis score: a prospective study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is common among subjects who undergo bariatric surgery and its postsurgical improvement has been reported. This study aimed to determine the evolution of liver disease evaluated through NAFLD fibrosis score 12 months after surgery.

METHODS

It is a prospective cohort study which evaluated patients immediately before and 12 months following Roux-en-Y gastric bypass (RYGB).

RESULTS

Mean score decreased from 1.142 to 0.066; surgery led to a resolution rate of advanced fibrosis of 55 %. Resolution was statistically associated with female gender, percentage of excess weight loss, postsurgical body mass index, postsurgical platelet count, and diabetes resolution.

CONCLUSIONS

As previously reported by studies in which postsurgical biopsies were performed, RYGB leads to a great resolution rate of liver fibrosis. Since postsurgical biopsy is not widely available and has a significant risk, calculation of NAFLD fibrosis score is a simple tool to evaluate this evolution through a noninvasive approach.

Cost-effectiveness of non-invasive methods for assessment and monitoring of liver fibrosis and cirrhosis in patients with chronic liver disease: systematic review and economic evaluation

BACKGROUND

Liver biopsy is the reference standard for diagnosing the extent of fibrosis in chronic liver disease; however, it is invasive, with the potential for serious complications. Alternatives to biopsy include non-invasive liver tests (NILTs); however, the cost-effectiveness of these needs to be established.

OBJECTIVE

To assess the diagnostic accuracy and cost-effectiveness of NILTs in patients with chronic liver disease.

DATA SOURCES

We searched various databases from 1998 to April 2012, recent conference proceedings and reference lists.

METHODS

We included studies that assessed the diagnostic accuracy of NILTs using liver biopsy as the reference standard. Diagnostic studies were assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Meta-analysis was conducted using the bivariate random-effects model with correlation between sensitivity and specificity (whenever possible). Decision models were used to evaluate the cost-effectiveness of the NILTs. Expected costs were estimated using a NHS perspective and health outcomes were measured as quality-adjusted life-years (QALYs). Markov models were developed to estimate long-term costs and QALYs following testing, and antiviral treatment where indicated, for chronic hepatitis B (HBV) and chronic hepatitis C (HCV). NILTs were compared with each other, sequential testing strategies, biopsy and strategies including no testing. For alcoholic liver disease (ALD), we assessed the cost-effectiveness of NILTs in the context of potentially increasing abstinence from alcohol. Owing to a lack of data and treatments specifically for fibrosis in patients with non-alcoholic fatty liver disease (NAFLD), the analysis was limited to an incremental cost per correct diagnosis. An analysis of NILTs to identify patients with cirrhosis for increased monitoring was also conducted.

RESULTS

Given a cost-effectiveness threshold of £20,000 per QALY, treating everyone with HCV without prior testing was cost-effective with an incremental cost-effectiveness ratio (ICER) of £9204. This was robust in most sensitivity analyses but sensitive to the extent of treatment benefit for patients with mild fibrosis. For HBV [hepatitis B e antigen (HBeAg)-negative)] this strategy had an ICER of £28,137, which was cost-effective only if the upper bound of the standard UK cost-effectiveness threshold range (£30,000) is acceptable. For HBeAg-positive disease, two NILTs applied sequentially (hyaluronic acid and magnetic resonance elastography) were cost-effective at a £20,000 threshold (ICER: £19,612); however, the results were highly uncertain, with several test strategies having similar expected outcomes and costs. For patients with ALD, liver biopsy was the cost-effective strategy, with an ICER of £822.

LIMITATIONS

A substantial number of tests had only one study from which diagnostic accuracy was derived; therefore, there is a high risk of bias. Most NILTs did not have validated cut-offs for diagnosis of specific fibrosis stages. The findings of the ALD model were dependent on assuptions about abstinence rates assumptions and the modelling approach for NAFLD was hindered by the lack of evidence on clinically effective treatments.

CONCLUSIONS

Treating everyone without NILTs is cost-effective for patients with HCV, but only for HBeAg-negative if the higher cost-effectiveness threshold is appropriate. For HBeAg-positive, two NILTs applied sequentially were cost-effective but highly uncertain. Further evidence for treatment effectiveness is required for ALD and NAFLD.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42011001561.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Does a calculated "NAFLD fibrosis score" reliably negate the need for liver biopsy in patients undergoing bariatric surgery?

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) represents the most common cause of chronic liver disease in the USA. Biopsy has been the standard for determining fibrosis but is invasive, costly, and associated with risk. Previous studies report a calculated "NAFLD fibrosis scores" (cNFS) as a means to overcome the need for biopsy. We compared cNFS versus biopsy-pathological scoring for patients undergoing bariatric surgery.

METHODS

We retrospectively reviewed patients with available preoperative labs and patient information undergoing Roux-en-Y gastric bypass (RYGBP) surgery at a single institution over a 5.5-year period. Biopsy samples were blind scored by a single hepatopathologist and compared with scores calculated using a previously reported cNFS.

RESULTS

Of the 225 patients that met the inclusion criteria, the mean body mass index was 44.6 ± 5.4 kg/m(2) and 85 % were female. Using the cNFS, 39.6 % of patients were categorized into low fibrosis, 52 % indeterminate, and 8.4 % high fibrosis groups. Analysis of fibrosis by pathology scoring demonstrated 2 of 89 (2.2 %) and 7 of 110 (3.4 %) had significant fibrosis in the low and intermediate groups, respectively. Conversely, in the high fibrosis group calculated by cNFS, only 6 of 19 (31.6 %) exhibited significant fibrosis by pathology scoring.

CONCLUSIONS

No definitive model for accurately predicting presence of NAFLD and fibrosis currently exits. Furthermore, under no circumstances should a clinical "NAFLD fibrosis score" replace liver biopsy at this time for RYGBP patients.

Meta-analysis: natural history of non-alcoholic fatty liver disease (NAFLD) and diagnostic accuracy of non-invasive tests for liver disease severity

BACKGROUND. NAFLD ranges from simple steatosis (SS) to non-alcoholic steatohepatitis (NASH). The natural history of NAFLD and the optimal strategy to identify subjects with progressive liver disease are unclear. Objectives. To assess the evidence in: (1) natural history of NAFLD; and (2) non-invasive methods to differentiate NAFLD histological subtypes. DESIGN AND SETTING. Among 4185 articles published on MEDLINE, Cochrane Library, EMBASE, Pubmed, national and International meeting abstracts through July 2010, 40 articles assessing the natural history of NAFLD and 32 articles evaluating the diagnostic accuracy of non-invasive tests against liver biopsy (LB) were included. MEASUREMENTS. Two reviewers retrieved articles and evaluated study quality by appropriate scores. Main outcomes were pooled using random- or fixed-effects models. RESULTS. NAFLD has an increased overall mortality (OR: 1.57, 95% CI: 1.18-2.10), deriving from liver-related and cardiovascular disease, and a 2-fold risk of diabetes. Compared to SS, NASH has a higher liver-related (OR for NASH: 5.71, 2.31-14.13; OR for NASH with advanced fibrosis: 10.06, 4.35-23.25), but not cardiovascular mortality (OR: 0.91, 0.42-1.98). Three non-invasive methods received independent validation: pooled AUROC, sensitivity and specificity of cytokeratin-18 for NASH are 0.82 (0.78-0.88), 0.78 (0.64-0.92), 0.87 (0.77-0.98). For NASH with advanced fibrosis, pooled AUROC, sensitivity and specificity of NAFLD fibrosis score and Fibroscan are 0.85 (0.80-0.93), 0.90 (0.82-0.99), 0.97 (0.94-0.99) and 0.94 (0.90-0.99), 0.94 (0.88-0.99) and 0.95 (0.89-0.99). CONCLUSIONS. NAFLD warrants screening for cardio-metabolic risk and for progressive liver disease. The combination of three noninvasive tests with LB may optimally individuate patients with NASH, with or without advanced fibrosis.