New Algorithm for the Integration of Ultrasound Into Cystic Fibrosis Liver Disease Screening

Cystic fibrosis hepatobiliary involvement: an update on imaging in diagnosis and monitoring

Analysis of the liver using imaging for persons with cystic fibrosis (CF) continues to evolve as new medical therapies are developed improving and extending life. In the 2010s, therapies targeted at modulating protein folding became available to those with CF. Therapeutic options have continued to expand, now providing both correction of protein folding and stabilization for most gene mutations that code for the CF transmembrane receptor protein (CFTR). Today, approximately 80% of persons with CF are eligible for highly effective modulator therapy. With these advancements, the impact of CF on the liver has become more complex, adding metabolism of CFTR modulators to intrinsic CF hepatobiliary involvement (CFHBI) and adding not previously appreciated vascular changes within the liver due to increased longevity in persons with CF. A combination of serum biomarkers and imaging is needed to add clarity to the diagnosis and monitoring of the severity of liver disease. A substantial portion of persons with CF will develop at least CFHBI and a subset will develop advanced cystic fibrosis-associated liver disease (aCFLD); therefore, diagnosis and monitoring need to begin in childhood. In this review, we cover the use of and need for imaging, including elastography, ultrasound, and magnetic resonance imaging (MRI), in diagnosing and monitoring CFHBI and its associated complications.

Cystic fibrosis screening, evaluation, and management of hepatobiliary disease consensus recommendations

Cystic fibrosis (CF) may cause a spectrum of hepatobiliary complications, including portal hypertension, multilobular cirrhosis, and liver failure. Current guidelines on the detection and monitoring of hepatobiliary complications in CF were published in 1999. The CF Foundation assembled a committee to evaluate research advances and formulate revised guidelines for CF-associated liver disease. A committee of hepatologists, gastroenterologists, pulmonologists, pharmacists, nurses, dietitians, individuals with CF, and the parents of a child with CF devised "population, intervention, comparison, and outcome" questions regarding hepatobiliary disease in CF. PubMed literature searches were performed for each population, intervention, comparison, and outcome question. Recommendations were voted on with 80% agreement required to approve a recommendation. Public comment on initial recommendations was solicited prior to the formulation of final recommendations. Thirty-one population, intervention, comparison, and outcome questions were assembled, 6401 manuscripts were title screened for relevance, with 1053 manuscripts undergoing detailed full-text review. Seven recommendations were approved for screening, 13 for monitoring of existing disease, and 14 for treatment of CF-associated hepatobiliary involvement or advanced liver disease. One recommendation on liver biopsy did not meet the 80% threshold. One recommendation on screening ultrasound was revised and re-voted on. Through a multidisciplinary committee and public engagement, we have assembled updated recommendations and guidance on screening, monitoring, and treatment of CF-associated hepatobiliary involvement and advanced liver disease. While research gaps remain, we anticipate that these recommendations will lead to improvements in CF outcomes through earlier detection and increased evidence-based approaches to monitoring and treatment.

Towards a Standardized Classification of the Hepatobiliary Manifestations in Cystic Fibrosis (CFHBI): A Joint ESPGHAN/NASPGHAN Position Paper

The broad spectrum of hepatobiliary involvement in cystic fibrosis (CF) has been commonly referred to as cystic fibrosis liver disease (CFLD). However, differences in the definitions of CFLD have led to variations in reported prevalence, incidence rates, and standardized recommendations for diagnosis and therapies. Harmonizing the description of the spectrum of hepatobiliary involvement in all people with CF (pwCF) is deemed essential for providing a reliable account of the natural history, which in turn supports the development of meaningful clinical outcomes in patient care and research. Recognizing this necessity, The European Society for Paediatric Gastroenterology Hepatology and Nutrition (ESPGHAN) and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) commissioned and tasked a committee to develop and propose a systematic classification of the CF hepatobiliary manifestations to increase uniformity, accuracy, and comparability for clinical, registry, and research purposes. This report describes the committee's combined expert position statement on hepatobiliary involvement in CF, which has been endorsed by NASPGHAN and ESPGHAN. We recommend using CFHBI (Cystic Fibrosis Hepato-Biliary Involvement) as the updated term to describe and classify all hepatobiliary manifestations in all pwCF. CFHBI encompasses the current extensive spectrum of phenotypical, clinical, or diagnostic expressions of liver involvement observed in pwCF. We present a schematic categorization of CFHBI, which may also be used to track and classify the changes and development of CFHBI in pwCF over time. The proposed classification for CFHBI is based on expert consensus and has not been validated for clinical practice and research purposes. Achieving validation should be an important aim for future research.

Heterogeneous liver on research ultrasound identifies children with cystic fibrosis at high risk of advanced liver disease

BACKGROUND

This study examines whether heterogeneous (HTG) pattern on liver ultrasound (US) identifies children at risk for advanced cystic fibrosis liver disease (aCFLD).

METHODS

Prospective 6-year multicenter case-controlled cohort study. Children with pancreatic insufficient cystic fibrosis (CF) aged 3-12 years without known cirrhosis underwent screening US. Participants with HTG were matched (by age, Pseudomonas infection status and center) 1:2 with participants with normal (NL) US pattern. Clinical status and laboratory data were obtained annually and US bi-annually for 6 years. Primary endpoint was development of nodular (NOD) US pattern consistent with aCFLD.

RESULTS

722 participants underwent screening US, with 65 HTG and 592 NL. Final cohort included 55 HTG and 116 NL with ≥ 1 follow-up US. ALT, AST, GGTP, FIB-4, GPR and APRI were higher, and platelets were lower in HTG compared to NL. HTG had a 9.5-fold increased incidence (95% confidence interval [CI]:3.4, 26.7, p<0.0001, 32.7% vs 3.4%) of NOD versus NL. HTG had a sensitivity of 82% and specificity of 75% for subsequent NOD. Negative predictive value of a NL US for subsequent NOD was 96%. Multivariate logistic prediction model that included baseline US, age, and log(GPR) improved the C-index to 0.90 compared to only baseline US (C-index 0.78). Based on survival analysis, 50% of HTG develop NOD after 8 years.

CONCLUSIONS

Research US finding of HTG identifies children with CF with a 30-50% risk for aCFLD. A score based on US pattern, age and GPR may refine the identification of individuals at high risk for aCFLD.

CLINICAL TRIAL REGISTRATION

Prospective Study of Ultrasound to Predict Hepatic Cirrhosis in CF: NCT 01,144,507 (observational study, no consort checklist).

Risk factors for more rapid progression of severe liver fibrosis in children with cystic fibrosis-related liver disease: A multi-center study validated by liver biopsy

BACKGROUND AND AIMS

Early identification of risk factors for the development of severe fibrosis in children with cystic fibrosis-related liver disease (CFLD) is crucial as promising therapies emerge.

METHODS

This multi-center cohort study of children with a priori defined CFLD from 1999 to 2016, was designed to evaluate the clinical utility of CF-specific characteristics and liver biomarkers assessed years prior to liver biopsy-proven CFLD to predict risk of developing severe fibrosis (F3-4) over time. Fibrosis was staged by Metavir classification.

RESULTS

The overall study cohort of 42 patients (F0-2 (n = 22) and F3-4 (n = 20)) was 57% male (n = 24) with median age of 7.6 years at baseline visit versus 10.3 years at biopsy. Median FEV₁ % predicted was lower in F3-4 participants at baseline versus F0-2 (59% vs. 85%; p = .002), while baseline FIB-4, APRI and GGT were higher in F3-4. Median splits for FIB-4 (≥.13), APRI (≥.36), GPR (≥.09), GGT (≥25.5), and FEV₁ % (<64%) were associated with more rapid progression to F3-4 (p < .01 for all). Using a combination of change/year in FIB-4, APRI, and GPR to predict F3-4, the AUROC was .81 (95% CI, .66, .96; p < .0001). For up to 5.8 years prior, thresholds for GPR were met 6.5-fold more rapidly, and those for APRI and FIB-4 were met 2.5-fold more rapidly, in those who progressed to F3-4 than those that did not.

CONCLUSIONS

This study suggests mild-moderate pulmonary dysfunction and higher liver biomarker indices at baseline may be associated with faster progression of CFLD.

Effects of CFTR modulators on serum biomarkers of liver fibrosis in children with cystic fibrosis

The cystic fibrosis (CF) transmembrane conductance regulator corrector/potentiator combinations lumacaftor/ivacaftor and elexacaftor/tezacaftor/ivacaftor improve sweat chloride, pulmonary function, and nutrition. Yet it is unclear whether they may also impact the progression of liver fibrosis, which is a substantial source of morbidity and mortality for patients with CF. We conducted a retrospective, single-center analysis of children and adolescents with CF treated with lumacaftor/ivacaftor and/or elexacaftor/tezacaftor/ivacaftor therapy, focusing on alterations in liver function tests and fibrosis indices using previously-established thresholds that corresponded with increased liver elastography. In pairwise comparisons of before and during treatment timepoints, we found that those with CF-associated liver involvement experienced significant decreases in gamma-glutamyl transferase, aspartate aminotransferase-to-platelet index, and gamma-glutamyl transferase-to-platelet ratio while on lumacaftor/ivacaftor. These differences were not observed in patients treated with elexacaftor/tezacaftor/ivacaftor, nor were they observed in patients without underlying CF-associated liver disease. These results provide the first evidence that lumacaftor/ivacaftor may improve liver fibrosis in children and adolescents with CF and suggest it may be beneficial in the treatment of CF-associated liver disease.

The Usefulness of Combining Noninvasive Methods for Early Identification and Potential Prevention of Cystic Fibrosis-Associated Liver Disease

Cystic fibrosis-associated liver disease is the third leading cause of morbidity and mortality in patients with cystic fibrosis (CF). Liver damage in the course of CF ranges from biochemical abnormalities to full-blown cirrhosis and may involve complicated processes like inflammation, fibrogenesis, remodeling, apoptosis, and cholestasis. Despite robust research in the field of CF, its complex pathogenesis is not fully understood. Because of the unknown pathogenesis, it is difficult to develop a highly sensitive and specific test or technology that is standardized, acceptable, and available at most pediatric institutions. The Cystic Fibrosis Foundation (CFF) recommends annual blood tests to screen for liver pathology, which often fails to identify early-onset liver disease. In this review article, we present the use of different liver indices and imaging modalities that can help identify liver disease at the onset and may help in its prevention. Although the disease is commonly diagnosed in the pediatric population, due to increased life expectancy, there is increasing evidence of liver disease in adults too. We believe that the tools we present in this review will help in the prevention of liver disease and thereby reduce the associated morbidity and mortality.

Long-term follow-up and liver outcomes in children with cystic fibrosis and nodular liver on ultrasound in a multi-center study

BACKGROUND

Nodular liver (NOD) in cystic fibrosis (CF) suggests advanced CF liver disease (aCFLD); little is known about progression of liver disease (LD) after detection of sonographic NOD.

METHODS

Clinical, laboratory, and ultrasound (US) data from Prediction by Ultrasound of the Risk of Hepatic Cirrhosis in CFLD Study participants with NOD at screening or follow-up were compared with normal (NL). Linear mixed effects models were used for risk factors for LD progression and Kaplan-Meier estimator for time-to-event.

RESULTS

54 children with NOD (22 screening, 32 follow-up) and 112 NL were evaluated. Baseline (BL) and trajectory of forced expiratory volume, forced vital capacity, height/BMI z-scores were similar in NOD vs NL. Platelets were lower in NOD at BL (250 vs 331×10³/microL; p < 0.001) and decreased by 8600/year vs 2500 in NL. Mean AST to Platelet Ratio Index (1.1 vs 0.4; p < 0.001), Fibrosis-4 Index (0.4 vs 0.2, p < 0.001), and spleen size z-score (SSZ) [1.5 vs 0.02; p < 0.001] were higher in NOD at BL; SSZ increased by 0.5 unit/year in NOD vs 0.1 unit/year in NL. Median liver stiffness (LSM) by transient elastography was higher in NOD (8.2 kPa, IQR 6-11.8) vs NL (5.3, 4.2-7, p < 0.0001). Over 6.3 years follow-up (1.3-10.3), 6 NOD had esophageal varices (cumulative incidence in 10 years: 20%; 95% CI: 0.0%, 40.0%), 2 had variceal bleeding, and 2 underwent liver transplantation; none had ascites or hepatic encephalopathy. No NL experienced liver-related events.

CONCLUSIONS

NOD developed clinically evident portal hypertension faster than NL without worse growth or lung disease.

Comparison of Transient Elastography, ShearWave Elastography, Magnetic Resonance Elastography and FibroTest as routine diagnostic markers for assessing liver fibrosis in children with Cystic Fibrosis

BACKGROUND AND OBJECTIVE

Reliable markers are needed for early diagnosis and follow-up of liver disease in Cystic Fibrosis (CF). The objective was to evaluate the diagnostic performance of Transient Elastography (TE), Real-Time ShearWave Ultrasound Elastography (SWE), Magnetic Resonance Elastography (MRE) and the FibroTest as markers of Cystic Fibrosis Liver Disease (CFLD).

METHODS

A monocentric prospective cross-modality comparison study was proposed to all children (6 to 18 years of age) attending the CF center. Based on liver ultrasound findings, participants were classified into 3 groups: multinodular liver or portal hypertension (Nodular US/PH, advanced CFLD), heterogeneous increased echogenicity (Heterogeneous US, CFLD) or neither (Normal/Homogeneous US, no CFLD). The 4 tests were performed on the same day. The primary outcome was the FibroTest value and liver stiffness measurements (LSM).

RESULTS

55 participants (mean age 12.6 ± 3.3 years; 25 girls) were included between 2015 and 2018: 23 in group Nodular US/PH, 8 in group Heterogeneous US and 24 in group Normal/Homogeneous US (including 4 with steatosis). LSM on TE, SWE and MRE were higher in participants with CFLD (groups Nodular US/PH and Heterogeneous US) compared to others (group Normal/Homogeneous US) (p<0.01), while FibroTest values did not differ (p = 0.09). The optimal cut-off values for predicting CFLD on TE, SWE and MRE were 8.7 (AUC=0.83, Se=0.71, Sp=0.96), 7.8 (AUC=0.85, Se=0.73, Sp=0.96) and 4.15 kPa (AUC=0.68, Se=0.73, Sp=0.64), respectively. LSM predicted the occurrence of major liver-related events at 3 years. TE and SWE were highly correlated (Spearman's ρ=0.9) and concordant in identifying advanced CFLD (Cohen's κ=0.84) while MRE was moderately correlated and concordant with TE (ρ=0.41; κ=36) and SWE (ρ=0.5; κ=0.50).

CONCLUSION

This study demonstrated excellent diagnostic performance of TE, SWE and MRE for the diagnosis of CFLD.

Recent advances in the early treatment of cystic fibrosis: Bridging the gap to highly effective modulator therapy

Highly effective modulator therapy (HEMT) for cystic fibrosis (CF) has been touted as one of the greatest advances to date in CF care. As these therapies are now available for many older children and adults with CF, marked improvement of their nutritional status, pulmonary and gastrointestinal symptoms has been observed. However, most infants and younger children are not current candidates for HEMT due to age and/or cystic fibrosis transmembrane conductance regulator (CFTR) mutation. For these young children, it is essential to provide rigorous monitoring and care to avoid potential disease sequelae while awaiting HEMT availability. The following article highlights recent advances in the care of infants and young children with CF with regard to surveillance and treatment of nutritional, pulmonary, and gastrointestinal disorders. Recent clinical trials in this population are also reviewed.

Gamma-glutamyl transpeptidase-to-platelet ratio as a biomarker of liver disease and hepatic fibrosis severity in paediatric Cystic Fibrosis

BACKGROUND

Cystic fibrosis (CF)-associated liver disease (CFLD) causes significant morbidity and mortality in children with CF. Diagnosis of liver disease prior to development of cirrhosis or portal hypertension (PHT) is challenging. While imaging modalities using Elastography show great promise they are still not widely available to all clinicians. This study investigated gamma-glutamyl transpeptidase-to-platelet ratio (GPR) as a non-invasive biomarker to detect liver disease and stage fibrosis severity in children with CF.

METHODS

237 children were enroled including 76 with CFLD and 161 with CF and no detectable liver disease (CFnoLD). CFLD was diagnosed using standard clinical, biochemical and imaging practice guidelines. Hepatic fibrosis was staged on liver biopsies available from 54 children with CFLD. Serum liver biochemistry was used to calculate GPR (median, [IQR]) and receiver operating characteristics (ROC) analysis assessed utility to detect liver disease and stage fibrosis severity.

RESULTS

GPR was significantly increased in CFLD versus CFnoLD (0.33 [0.19-0.96] vs. 0.15 [0.11-0.21], P<0.0001). GPR demonstrated good diagnostic utility for detecting CFLD with an area under the curve (AUC) of 0.81 (95% confidence Interval [CI] [0.75-0.87]; P<0.0001), with sensitivity of 74% and specificity of 73%, using a cut-off of 0.20. GPR increased with increasing hepatic fibrosis stage. GPR discriminated both moderate-advanced (F2-F4) fibrosis vs. F0-F1 (AUC=0.82; 95%CI [0.71-0.94]; P<0.0001) and advanced (F3-F4) fibrosis vs. F0-F2 (AUC=0.77; 95%CI [0.64-0.90]; P = 0.004), with a cut-off 0.32 and 0.61, respectively. An elevated GPR of >0.84 was predictive of PHT at diagnosis of CFLD (AUC=0.81; 95%CI [0.67-0.95]; P = 0.0003).

CONCLUSIONS

GPR demonstrates good diagnostic utility for assessing the presence of liver disease, PHT and hepatic fibrosis severity in children with CF. These findings will aid in better identification of patients at risk for CF-related liver involvement and the potential for more targeted and timely follow-up and treatment.

Emerging clinical perspectives in cystic fibrosis liver disease

PURPOSE OF REVIEW

Liver disease (CFLD) as a complication of cystic fibrosis is recognized as a more severe disease phenotype in both children and adults. We review recent advances in understanding the disease mechanism and consider the implications of new strategies for the diagnosis and management of cystic fibrosis in those with evidence of clinically significant liver disease.

RECENT FINDINGS

Evidence suggests that the prevalence of CFLD has not declined with the introduction of newborn screening. Furthermore, children with CFLD, who have been diagnosed with cystic fibrosis following newborn screening continue to have a much higher mortality rate compared with those with no liver disease. There is further data suggesting noncirrhotic obliterative portal venopathy as the predominant pathological mechanism in the majority of children and young adults receiving a liver transplantation. Little progress has been made in developing an accurate noninvasive test for early diagnosis or monitoring disease progression in CFLD. The benefit of new modulator therapies is not well understood in those with established CFLD, whereas the risk of hepatotoxicity as a complication of treatment must be carefully monitored.

SUMMARY

Better understanding of the pathophysiology of CFLD would allow a standardized approach to diagnosis, with the potential to improve outcomes for those with CFLD.

Non-invasive Diagnostic Tests in Cystic Fibrosis-Related Liver Disease: A Diagnostic Test Accuracy Network Meta-Analysis

Background and Aims: Cystic fibrosis-related liver disease (CFLD) is one of the leading causes of morbidity and mortality in cystic fibrosis (CF). Several non-invasive diagnostic methods have been proposed as screening tools for CFLD. Our aim was to rank all available non-invasive modalities for diagnostic performance.

Methods: A systematic search was performed in five medical databases to find studies which reported on any single or composite non-invasive diagnostic test (as an index test) compared to the Debray, the EuroCare or the Colombo criteria (as a reference standard). Ranking was carried out with a Bayesian diagnostic test accuracy network meta-analysis based on superiority indices, calculated for pooled sensitivity (Se) and specificity (Sp) with a 95% confidence interval (CI). The study was registered under CRD42020155846 in PROSPERO.

Results: Fifteen studies with 15 index tests and a combination of them were included. The New criteria proposed by Koh et al. – which represent a composite diagnostic definition for CFLD including liver biochemistry, ultrasonography, transient elastography and fibrosis markers—had the best performance for detecting CFLD (Se:94%[CI:58–100], Sp:72%[CI:52–84]); while transient elastography (Se:65%[CI:56–74], Sp:88%[CI:84–91]) and a combination of it with a tissue inhibitor of metalloproteinase-4 measurement (Se:78%[CI:30–100], Sp:64%[CI:18–95%]) proved to be the second and third best options, respectively. In the imaging techniques subgroup, transient elastography (Se:66%[CI:57–72], Sp:88%[CI:85–91%]), acoustic radiation force impulse in the right lobe (Se:54%[CI:33–74], Sp:88%[CI:66–96]) and that in the left lobe (Se:55%[CI:23–81], Sp:82%[CI:50–95]) were ranked the highest. Comparing biochemical markers/fibrosis indices, the measurement of the Forns index (Se:72%[CI:25–99], Sp:63%[CI:16–94]), the aspartate aminotransferase-to-platelet ratio (Se:55%[CI:41–68], Sp:83%[CI:66–89]) and alkaline phosphatase (Se:63%[CI:18–93], Sp:64%[CI:19–95]) were ranked the highest.

Conclusion: The New criteria show the best diagnostic performance. In clinical practice, transient elastography seems to be a simple, cheap and non-invasive tool, outperforming imaging, biochemical and fibrosis tests for detecting CFLD. Further studies are needed to validate our findings.

Clinical use of shear-wave elastography for detecting liver fibrosis in children and adolescents with cystic fibrosis

BACKGROUND

Complications from liver cirrhosis are a leading cause of death in children with cystic fibrosis. Identifying children at risk for developing liver cirrhosis and halting its progression are critical to reducing liver-associated mortality.

OBJECTIVE

Quantitative US imaging, such as shear-wave elastography (SWE), might improve the detection of liver fibrosis in children with cystic fibrosis (CF) over gray-scale US alone. We incorporated SWE in our pediatric CF liver disease screening program and evaluated its performance using magnetic resonance (MR) elastography.

MATERIALS AND METHODS

Ninety-four children and adolescents with CF underwent 178 SWE exams, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and platelet measurements. Of these, 27 children underwent 34 MR elastography exams. We evaluated SWE performance using 6-MHz and 9-MHZ point SWE, and 9-MHz two-dimensional (2-D) SWE.

RESULTS

The 6-MHz point SWE was the only method that correlated with MR elastography (r=0.52; 95% confidence interval [CI] 0.20-0.74; P=0.003). SWE of 1.45 m/s distinguished normal from abnormal MR elastography (79% sensitivity, 100% specificity, 100% positive predictive value [PPV], 55% negative predictive value [NPV], area under the receiver operating characteristic [AUROC] curve 0.94). SWE of 1.84 m/s separated mild-moderate (3.00-4.77 kPa) from severe (>4.77 kPa) MR elastography (88% sensitivity, 86% specificity, 78% PPV, 93% NPV, AUROC 0.79). Elevations of AST, ALT, GGT and thrombocytopenia were associated with higher SWE. AST-to-platelet ratio index of 0.42, fibrosis-4 of 0.29, and GGT-to-platelet ratio of 1.43 all had >95% NPV for SWE >1.84 m/s.

CONCLUSION

Given its correlation with MR elastography, SWE might be a clinically useful predictor of liver fibrosis. We identified imaging criteria delineating the use of SWE to identify increased liver stiffness in children with CF. With multicenter validation, these data might be used to improve the detection and monitoring of liver fibrosis in children with CF.

Cystic fibrosis foundation consensus statements for the care of cystic fibrosis lung transplant recipients

Cystic fibrosis (CF) is the indication for transplantation in approximately 15% of recipients worldwide, and Cystic Fibrosis Lung Transplant Recipients (CFLTRs) have excellent long-term outcomes. Yet, CFLTRs have unique comorbidities that require specialized care. The objective of this document is to provide recommendations to CF and lung transplant clinicians for the management of perioperative and underlying comorbidities of CFLTRs and the impact of transplantation on these comorbidities. The Cystic Fibrosis Foundation (CFF) organized a multidisciplinary committee to develop CF Lung Transplant Clinical Care Recommendations. Three workgroups were formed to develop focused questions. Following a literature search, consensus recommendations were developed by the committee members based on literature review, committee experience and iterative revisions, and in response to public comment. The committee formulated 32 recommendation statements in the topics related to infectious disease, endocrine, gastroenterology, pharmacology, mental health and family planning. Broadly, the committee recommends close coordination of care between the lung transplant team, the cystic fibrosis care center, and specialists in other disciplines with experience in the care of CF and lung transplant recipients. These consensus statements will help lung transplant providers care for CFLTRs in order to improve post-transplant outcomes in this population.

Cystic Fibrosis-related Liver Disease: The Next Challenge

Up to 40% of individuals with cystic fibrosis have cystic fibrosis-related liver disease (CFLD); however, only 5% to 10% will have clinically evident disease. With the introduction of powerful cystic fibrosis transmembrane conductance regulator (CFTR) enhancers, effective treatment for cystic fibrosis is available. The role of CFTR enhancers in liver disease is unknown at this time. The traditionally accepted theory of the pathogenesis of CFLD is being questioned. A different pathogenesis may lead to new ways to treat CFLD. The way that CFLD is diagnosed and monitored is evolving as new imaging technology become available.

Barrier to using APRI and GPR as identifiers of cystic fibrosis liver disease

Cystic fibrosis-associated liver disease (CFLD) is the third most common cause of death in cystic fibrosis (CF). Poor ability to identify early, non-cirrhotic liver disease hampers interventions to mitigate complications associated with CFLD and potential early therapies that may halt the progression of cirrhosis. Liver fibrosis indices, such as APRI, FIB-4, and GPR, are minimally invasive biomarkers that may be useful for the detection and monitoring of CFLD. However, variability in the upper limit of normal values used in these calculations makes it difficult to compare results across research studies and identify appropriate indices cutoffs. Previously published APRI and GPR values are re-calculated using the same upper limit of normal values as recently published data on APRI and GPR, highlighting the importance of standardized upper limit of normal values for calculating liver fibrosis indices in CFLD detection and monitoring.

Biopsy Validated Study of Biomarkers for Liver Fibrosis and Transplant Prediction in Inherited Cholestasis

Alagille syndrome (ALGS) and progressive familial intrahepatic cholestasis (PFIC) are inherited cholestatic disorders with risk of developing end‐stage liver disease requiring liver transplantation (LT). We investigated aspartate aminotransferase‐to‐platelet ratio index (APRI), Fibrosis‐4 score (FIB‐4), and conjugated bilirubin as biomarkers to assess fibrosis severity and risk for LT among children with ALGS and PFIC. This multicenter, cross‐sectional study included 64 children with ALGS or PFIC (per genetics or strict clinical criteria) with APRI, FIB‐4, and conjugated bilirubin levels collected within ±90 days of their most recent liver biopsy. A single, blinded pathologist staged all biopsies (metavir; F0‐F2: nonsevere, F3‐F4: severe). Logistic regression and area under the receiver operating characteristic curve analysis (AUC) were used to assess biomarker associations with fibrosis severity and risk for LT. In ALGS, only APRI distinguished F3‐F4 (AUC 0.72, P = 0.012), with a cutoff greater than 2.97 demonstrating a sensitivity of 61.5% (95% confidence interval 0.32, 0.86) and specificity of 81.5% (0.62, 0.94). In ALGS, a 50% increase of APRI increased the odds of F3‐F4 by 1.31‐fold (1.04, 1.65; P = 0.023). In ALGS, APRI (AUC 0.87; P < 0.001) and FIB‐4 (AUC 0.84; P < 0.001) were able to predict risk for LT. In PFIC, only APRI distinguished F3‐4 (AUC 0.74, P = 0.039), with a cutoff greater than 0.99 demonstrating a sensitivity of 80% (0.44, 0.98) and specificity of 64.3% (0.35, 0.87). In PFIC, only FIB‐4 was able predict risk for LT (AUC 0.80; P = 0.002). In ALGS or PFIC, conjugated bilirubin could not distinguish F3‐F4 or predict risk for LT. Conclusion: This liver biopsy–validated study suggests that APRI is able to distinguish F3‐F4 from F0‐F2 in ALGS and PFIC. APRI and FIB‐4 may also serve as predictors of risk for LT in ALGS (APRI and FIB‐4) and PFIC (FIB‐4).

A longitudinal assessment of non-invasive biomarkers to diagnose and predict cystic fibrosis-associated liver disease

BACKGROUND & AIMS

A practical, inexpensive, and non-invasive biomarker of liver fibrosis is needed as a reliable screening test for cystic fibrosis-associated liver disease (CFLD). Studies have shown the utility of AST to Platelet Ratio Index (APRI), fibrosis index based on 4 factors (FIB-4), and gamma-glutamyl transferase (GGT) as good biomarkers for identifying CFLD. The goal of the study was to evaluate the effectiveness of APRI, FIB-4, AST/ALT ratio, platelet count, GGT, and GGT platelet ratio (GPR) in predicting CFLD development.

METHODS

Data was collected from CF Foundation Patient Registry for patients aged 3-21 years at Johns Hopkins from January 1, 2002 to December 31, 2014. Collected data included demographic characteristics, presence of splenomegaly, hepatomegaly, ascites, and variceal bleeding, AST, ALT, GGT, platelet count, and FEV₁. The sensitivity and specificity of each biomarker were analyzed and reported by the area under receiver operating characteristic (AUROC) curve.

RESULTS

By the end of the study, 144 "healthy" CF, 12 CFLD, 19 CF-associated pulmonary disease (CFPD), and 4 CFLD with CFPD cases were identified. APRI scores were higher in CFLD, 0.85 versus 0.28 in "healthy" CF and 0.23 in CFPD groups (p<0.001). GPR had the highest AUROC curve at 0.91.

CONCLUSIONS

GPR, GGT, APRI score, and platelet count were potentially useful biomarkers while FIB-4 did not predict CFLD development. Cost-effectiveness studies are needed to analyze the utility of these biomarkers in clinical practice.

Cystic fibrosis-associated liver disease in children

As improvements in nutritional and pulmonary care increase the life expectancy of cystic fibrosis (CF) patients, CF-associated liver disease (CFLD) is emerging as a cause of mortality. CFLD is the third leading cause of death in CF patients. We performed a search on PubMed and Google Scholar for published articles on CFLD. We reviewed the articles found in the literature search and gave priority to recent publications and studies with larger sample sizes. The prevalence of CFLD in the CF population is around 23% with a range of 2-62% and that prevalence increases linearly with age from 3.7% at age 5 to 32.2% at age 30. CFLD can present clinically in various ways such as hepatomegaly, variceal hemorrhage, persistent elevation of liver enzymes, and micro-gallbladder. Due to the focal nature of fibrosis in majority cases of CFLD, liver biopsies are sparsely performed for diagnosis or the marker of liver fibrosis. Although the mechanism of CFLD development is still unknown, many potential factors are reported. Some mutations of CFTR such as having a homozygous F508del mutation has been reported to increase the risk of developing CFLD and its severity. Having the SERPINA1 Z allele, a history of pancreatic insufficiency, a history meconium ileus, CF-related diabetes, or being male increases the risk of developing CFLD. Environmental factors do not appear to have significant effect on modulating CFLD development. Ursodeoxycholic acid is commonly used to treat or prevent CFLD, but the efficacy of this treatment is questionable.

Hepatic manifestations of cystic fibrosis

PURPOSE OF REVIEW

Liver disease in cystic fibrosis (CF) usually develops before puberty, is often asymptomatic and slowly progressive. Multilobular cirrhosis develops in approximately 5-10% of patients by the age of 18, and is a significant contributor to the morbidity and mortality. No therapy, including ursodeoxycholic acid and cystic fibrosis transmembrane conductance regulator correctors or potentiators, has proven effective to prevent or halt the progression of liver disease towards cirrhosis and portal hypertension. This review provides the current knowledge in the epidemiology of CF liver disease and development of noninvasive tools to assess liver disease severity and progression overtime in order to optimize clinical management and therapeutic options.

RECENT FINDINGS

Liver disease not only develops during childhood but also later in the lifetime of patients with CF; the incidence of cirrhosis with portal hypertension increases progressively reaching 10% by age 30. Several noninvasive tools to measure liver stiffness as an indirect measure of fibrosis are being investigated, and show promising results for the assessment of early stages of liver fibrosis and disease progression.

SUMMARY

Identifying noninvasive biomarkers is fundamental to improving early diagnosis, monitoring disease evolution and measuring treatment effects. A prerequisite is the use of consistent definitions for CF- liver disease (LD) in clinical trials.