Liver disease as risk factor for cystic fibrosis-related diabetes development

Clinical and genetic risk factors for cystic fibrosis-related liver disease in Egyptian CF children: A single-center experience

BACKGROUND

Cystic fibrosis (CF) is an autosomal recessive disease. It affects multiple organ systems, including the liver, leading to CF-related liver disease (CFLD). It was noted that CFLD in Egyptian children with CF is more common than in non-Egyptian people with CF (pwCF). This study aimed to determine the incidence of CFLD and the potential risk factors for developing CFLD in Egyptian children. The correlation between CFLD and the various genotypes prevalent in Egyptian CF children will be discussed. In addition, comparison of CFLD in Egyptian and non-Egyptian CF patients will be presented.

METHODS

This cross-sectional study included 50 pwCF from Ain Sham University's Pediatric Pulmonology Clinic in Children's Hospital, Cairo, Egypt. The sweat chloride test and genetic studies were done at the time of diagnosis. Additionally, all subjects underwent detailed history taking, laboratory investigations, clinical assessment, and pelvic abdominal ultrasound for evaluation of hepatic involvement.

RESULTS

One-third of the Egyptian children with CF were found to have liver disease. The following independent risk factors for developing CFLD were identified as: male sex, severe genetic mutation (class I and II), long duration of CF disease, early onset of the CF, pancreatic insufficiency, as well as history of meconium ileus. In addition, diabetes mellitus and severe lung disease were proven to significantly increase the risk of developing CFLD.

CONCLUSION

CFLD is common in Egyptian pwCF. CFLD's risk factors are similar to other reported research from other countries in the region.

A Unique Mutation in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Gene Causing Cystic Fibrosis in a Pakistani Child: A Case Highlighting the Need for More Awareness

Cystic fibrosis (CF) is a recessively inherited disease most commonly seen in Caucasians. The mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene are responsible for the condition, and to date, more than 2000 mutations have been published in the literature. The most common mutation worldwide is F508del. Here, we reported a five-year-old child who presented to the clinic with a chronic cough. Her newborn screening for CF was negative, including 139 mutation panels done in India. The sweat chloride test was positive, and CF gene sequencing was reported as c.2489dup p. (Glu831GLYFS *5) homozygotes mutation in the CFTR gene (Online Mendelian Inheritance in Man (OMIM) *602421). To the best of our knowledge, this gene was first described and published in the literature.

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.

Characterization of glucose metabolism in youth with vs. without cystic fibrosis liver disease: A pilot study

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Severe CF-liver disease may exaggerate glucose abnormalities in patients with CFRD.

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CF-liver disease may decrease insulin clearance that fosters insulin resistance.

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Patients with CFRD and liver disease may warrant treatment other than insulin.

Background

Diabetes and liver disease are life-threatening complications of cystic fibrosis (CF). CF-liver disease is a risk factor for CF related diabetes (CFRD) development, but the underlying mechanisms linking the two co-morbidities are not known. The objective of this pilot study was to characterize glucose metabolism in youth with CF with and without liver disease.

Methods

In this two-center cross-sectional study, 20 youth with CF with and without liver disease underwent a 3-hour oral glucose tolerance test. Subjects were categorized by liver disease (LD) status [no LD, mild LD, severe LD] and diabetes status. Measures of glucose excursion, islet cell secretory responses, insulin sensitivity and clearance were obtained.

Results

Participants with severe LD had the highest fasting, peak, and glucose area under the curve over 3 h (AUC_3h) among individuals with CFRD (interaction p < 0.05). In parallel with glycemic changes, prandial β-cell secretory response (AUC _{C-peptide 3h}) was lower in those with severe LD compared to mild or no LD (p < 0.01). There was a trend of higher HOMA-IR in those with severe LD (p = 0.1) as well as lower fasting insulin clearance in those with mild and severe LD compared to no LD (p = 0.06) and lower prandial insulin clearance in severe LD among those with CFRD (interaction p = 0.1).

Conclusion

In this small cohort, subjects with severe LD tended to have more impaired glycemia, insulin secretion, insulin sensitivity and clearance. Larger studies are imperative to define the pathogenesis to inform clinical care guidelines in terms of CFRD screening, diagnosis, and treatment options.

Cystic Fibrosis-Related Diabetes in Poland

Cystic fibrosis (CF) is the most common autosomal recessive inherited monogenic disease in Caucasians. As medical technology progresses and the quality of patient care improves, the survival time of patients with CF has increased, which results in more frequent comorbidities such as cystic fibrosis-related diabetes (CFRD). CFRD is the result of abnormal glucose metabolism characterized primarily by insulin deficiency, exacerbated periodically by insulin resistance. The aim of our study was to analyze the epidemiology of patients with CFRD in Poland on the basis of data collected from six CF treatment centers. Analyses were performed on 1157 CF patients who were treated at one of the six CF care centers. CFRD was diagnosed according to standard criteria. All data including demographics, types of CFTR mutations, CFRD duration, and microorganisms in the sputum were obtained from the patients’ medical history. Our study indicates that the prevalence of CFRD in Poland is 12.9%. CFRD was most often diagnosed between the ages of 11 and 20 (60% of patients), while 23% of patients were diagnosed between 21 and 30 years of age. Furthermore, we observed that approximately 3–5% of patients under the age of 10 had CFRD. We found out that the type of mutation did not affect the frequency of CFRD development. Factors that increased the risk of developing CFRD include underweight and chronic Pseudomonas aeruginosa infection. Due to the extended lifespan of CF patients, the number of CFRD patients is currently increasing. We believe that the results of our study may complement information from other studies or may be useful in planning health policy in Poland.

Cystic fibrosis related liver disease and endocrine considerations

Cystic fibrosis-liver disease (CFLD) is one of the most common non-pulmonary complications in the CF population, is associated with significant morbidity and represents the third leading cause of mortality in those with CF. CFLD encompasses a broad spectrum of hepatobiliary manifestations ranging from mild transaminitis, biliary disease, hepatic steatosis, focal biliary cirrhosis and multilobular biliary cirrhosis. The diagnosis of CFLD and prediction of disease progression remains a clinical challenge. The identification of novel CFLD biomarkers as well as the role of newer imaging techniques such as elastography to allow for early detection and intervention are active areas of research focus. Biliary cirrhosis with portal hypertension represents the most severe spectrum of CFLD, almost exclusively develops in the pediatric population, and is associated with a decline in pulmonary function, poor nutritional status, and greater risk of hospitalization. Furthermore, those with CFLD are at increased risk for vitamin deficiencies and endocrinopathies including CF-related diabetes, CF-related bone disease and hypogonadism, which can have further implications on disease outcomes and management. Effective treatment for CFLD remains limited and current interventions focus on optimization of nutritional status, identification and treatment of comorbid conditions, as well as early detection and management of CFLD specific sequelae such as portal hypertension or variceal bleeding. The extent to which highly effective modulator therapies may prevent the development or modify the progression of CFLD remains an active area of research. In this review, we discuss the challenges with defining and evaluating CFLD and the endocrine considerations and current management of CFLD.

The Gut-Lung Axis in Cystic Fibrosis

Cystic fibrosis (CF) is a heritable, multiorgan disease that impacts all tissues that normally express cystic fibrosis transmembrane conductance regulator (CFTR) protein. While the importance of the airway microbiota has long been recognized, the intestinal microbiota has only recently been recognized as an important player in both intestinal and lung health outcomes for persons with CF (pwCF). Here, we summarize current literature related to the gut-lung axis in CF, with a particular focus on three key ideas: (i) mechanisms through which microbes influence the gut-lung axis, (ii) drivers of microbiota alterations, and (iii) the potential for intestinal microbiota remediation.

Cystic Fibrosis-Related Diabetes (CFRD): Overview of Associated Genetic Factors

Cystic fibrosis (CF) is the most common autosomal recessive disease in the Caucasian population and is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene that encodes for a chloride/bicarbonate channel expressed on the membrane of epithelial cells of the airways and of the intestine, as well as in cells with exocrine and endocrine functions. A common nonpulmonary complication of CF is cystic fibrosis-related diabetes (CFRD), a distinct form of diabetes due to insulin insufficiency or malfunction secondary to destruction/derangement of pancreatic betacells, as well as to other factors that affect their function. The prevalence of CFRD increases with age, and 40–50% of CF adults develop the disease. Several proposed hypotheses on how CFRD develops have emerged, including exocrine-driven fibrosis and destruction of the entire pancreas, as well as contrasting theories on the direct or indirect impact of CFTR mutation on islet function. Among contributors to the development of CFRD, in addition to CFTR genotype, there are other genetic factors related and not related to type 2 diabetes. This review presents an overview of the current understanding on genetic factors associated with glucose metabolism abnormalities in CF.

The Potential Causes of Cystic Fibrosis-Related Diabetes

Cystic fibrosis (CF) is a genetic disease caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). Cystic fibrosis-related diabetes (CFRD) is the most common comorbidity, affecting more than 50% of adult CF patients. Despite this high prevalence, the etiology of CFRD remains incompletely understood. Studies in young CF children show pancreatic islet disorganization, abnormal glucose tolerance, and delayed first-phase insulin secretion suggesting that islet dysfunction is an early feature of CF. Since insulin-producing pancreatic β-cells express very low levels of CFTR, CFRD likely results from β-cell extrinsic factors. In the vicinity of β-cells, CFTR is expressed in both the exocrine pancreas and the immune system. In the exocrine pancreas, CFTR mutations lead to the obstruction of the pancreatic ductal canal, inflammation, and immune cell infiltration, ultimately causing the destruction of the exocrine pancreas and remodeling of islets. Both inflammation and ductal cells have a direct effect on insulin secretion and could participate in CFRD development. CFTR mutations are also associated with inflammatory responses and excessive cytokine production by various immune cells, which infiltrate the pancreas and exert a negative impact on insulin secretion, causing dysregulation of glucose homeostasis in CF adults. In addition, the function of macrophages in shaping pancreatic islet development may be impaired by CFTR mutations, further contributing to the pancreatic islet structural defects as well as impaired first-phase insulin secretion observed in very young children. This review discusses the different factors that may contribute to CFRD.

Cystic Fibrosis-related Liver Disease is Associated With Increased Disease Burden and Endocrine Comorbidities

BACKGROUND

Cystic fibrosis-related liver disease (CFLD) is the leading nonpulmonary cause of mortality in cystic fibrosis (CF). We evaluated and compared the burden of disease and nonrespiratory comorbidities of those with severe CFLD and those without (noCFLD).

METHODS

A retrospective nationwide (Australia) longitudinal review (from 1998 to 2016) of severe CFLD patients compared with noCFLD controls (matched 1 : 1 for age, genotype, pancreatic insufficiency, and center).

RESULTS

One hundred sixty-six patients with severe CFLD and 166 with noCFLD were identified. Forced expiratory volume in 1 second percentage of predicted (FEV1%) was significantly lower in CFLD than noCFLD across all ages (estimate [SE] -6.05% [2.12]; P = 0.004). Median (IQR) hospitalizations per patient per year were higher in CFLD than noCFLD for: respiratory indications (0.6 [0.2-1.3] vs 0.4 [0.1-0.9]; P = 0.002); gastrointestinal indications (0.09 [0-0.2] vs 0 [0-0.05]; P < 0.001); and other indications (0.05 [0-0.2] vs 0 [0-0.1]; P = 0.03). In the CFLD cohort, there was increased use of nasogastric (12.6% vs 5.4%; OR 2.51 [95% CI 1.06-6.46]; P = 0.03) and gastrostomy nutritional supplementation (22.9% vs 13.2%; OR 1.93 [95% CI 1.05-3.63]; P = 0.03). Additionally, the CFLD cohort had a higher frequency of bone diseases, osteopenia (26.5% vs 16.8%; OR 1.77 [95%CI 1.01-3.15]; P = 0.04) and osteoporosis (16.2% vs 8.4%; OR 2.1 [95% CI 1.01-4.52]; P = 0.04), as well as CF-related diabetes (38.5% vs 19.2%; OR 2.61 [95% CI 1.55-4.47]; P = 0.001).

CONCLUSIONS

Patients with severe CFLD have greater disease burden, with higher number of hospitalizations (both respiratory and nonrespiratory indications), nutritional interventions, and are at higher risk of CF-related bone disease and diabetes.

Lumacaftor/ivacaftor therapy is associated with reduced hepatic steatosis in cystic fibrosis patients

BACKGROUND

Hepatic steatosis is a common form of cystic fibrosis associated liver disease (CFLD) seen in an estimated 15%-60% of patients with cystic fibrosis (CF). The pathophysiology and health implications of hepatic steatosis in cystic fibrosis remain largely unknown. In the general population, hepatic steatosis is strongly associated with insulin resistance and type 2 diabetes. Cystic fibrosis related diabetes (CFRD) impacts 40%-50% of CF adults and is characterized by both insulin insufficiency and insulin resistance. We hypothesized that patients with CFRD would have higher levels of hepatic steatosis than cystic fibrosis patients without diabetes.

AIM

To determine whether CFRD is associated with hepatic steatosis and to explore the impact of lumacaftor/ivacaftor therapy on hepatic steatosis in CF.

METHODS

Thirty patients with CF were recruited from a tertiary care medical center for this cross-sectional study. Only pancreatic insufficient patients with CFRD or normal glucose tolerance (NGT) were included. Patients with established CFLD, end stage lung disease, or persistently elevated liver enzymes were excluded. Mean magnetic resonance imaging (MRI) proton density fat fraction (PDFF) was obtained for all participants. Clinical characteristics [age, sex, body mass index, percent predicted forced expiratory volume at 1 s (FEV1), lumacaftor/ivacaftor use] and blood chemistries were assessed for possible association with hepatic steatosis. Hepatic steatosis was defined as a mean MRI PDFF > 5%. Patients were grouped by diabetes status (CFRD, NGT) and cystic fibrosis transmembrane conductance regulator (CFTR) modulator use (lumacaftor/ivacaftor, no lumacaftor/ivacaftor) to determine between group differences. Continuous variables were analyzed with a Wilcoxon rank sum test and discrete variables with a Chi square test or Fisher’s exact test.

RESULTS

Twenty subjects were included in the final analysis. The median age was 22.3 years (11.3-39.0) and median FEV1 was 77% (33%-105%). Twelve subjects had CFRD and 8 had NGT. Nine subjects were receiving lumacaftor/ivacaftor. The median PDFF was 3.0% (0.0%-21.0%). Six subjects (30%) had hepatic steatosis defined as PDFF > 5%. Hepatic fat fraction was significantly lower in patients receiving lumacaftor/ivacaftor (median, range) (2.0%, 0.0%-6.4%) than in patients not receiving lumacaftor/ivacaftor (4.1%, 2.7-21.0%), P = 0.002. Though patients with CFRD had lower PDFF (2.2%, 0.0%-14.5%) than patients with NGT (4.9%, 2.4-21.0%) this did not reach statistical significance, P = 0.06. No other clinical characteristic was strongly associated with hepatic steatosis.

CONCLUSION

Use of the CFTR modulator lumacaftor/ivacaftor was associated with significantly lower hepatic steatosis. No association between CFRD and hepatic steatosis was found in this cohort.

Cystic Fibrosis Liver Disease: Outcomes and Risk Factors in a Large Cohort of French Patients

Cystic fibrosis (CF)-related liver disease (CFLD) is a common symptom in patients with CF. However, its prevalence, risk factors, and evolution are unclear. We analyzed a large database of patients with CF to investigate the incidence of CFLD, its related risk factors, and the use and effect of ursodeoxycholic acid (UDCA) treatment. We retrospectively analyzed 3,328 CF patients with pancreatic insufficiency born after 1985 and recruited into the French CF Modifier Gene Study since 2004. We determined liver status, age at CFLD and severe CFLD onset, sex, CFTR genotype, history of meconium ileus, treatment with UDCA, and respiratory and nutritional status. The incidence of CFLD increased by approximately 1% every year, reaching 32.2% by age 25. The incidence of severe CFLD increased only after the age of 5, reaching 10% by age 30. Risk factors for CFLD and severe CFLD were male sex, CFTR F508del homozygosity, and history of meconium ileus. Increasingly precocious initiation of UDCA treatment did not change the incidence of severe CFLD. Finally, patients with severe CFLD had worse lung function and nutritional status than other CF patients. Conclusion: CFLD occurs not only during childhood but also later in the lifetime of patients with CF; male sex, CFTR F508del homozygosity, and history of meconium ileus are independent risk factors for CFLD development; earlier use of UDCA over the last 20 years has not changed the incidence of severe CFLD, leading to questions about the use of this treatment in young children given its possible adverse effects.

Clinical expression of cystic fibrosis in a large cohort of Italian siblings

Background

A clinical heterogeneity was reported in patients with Cystic Fibrosis (CF) with the same CFTR genotype and between siblings with CF.

Methods

We investigated all clinical aspects in a cohort of 101 pairs of siblings with CF (including 6 triplets) followed since diagnosis.

Results

Severe lung disease had a 22.2% concordance in sib-pairs, occurred early and the FEV₁% at 12 years was predictive of the severity of lung disease in the adulthood. Similarly, CF liver disease occurred early (median: 15 years) and showed a concordance of 27.8% in sib-pairs suggesting a scarce contribution of genetic factors; in fact, only 2/15 patients with liver disease in discordant sib-pairs had a deficiency of alpha-1-antitrypsin (a known modifier gene of CF liver phenotype). CF related diabetes was found in 22 pairs (in 6 in both the siblings). It occurred later (median: 32.5 years) and is strongly associated with liver disease. Colonization by P. aeruginosa and nasal polyposis that required surgery had a concordance > 50% in sib-pairs and were poorly correlated to other clinical parameters. The pancreatic status was highly concordant in pairs of siblings (i.e., 95.1%) but a different pancreatic status was observed in patients with the same CFTR mutations. This suggests a close relationship of the pancreatic status with the “whole” CFTR genotype, including mutations in regulatory regions that may modulate the levels of CFTR expression. Finally, a severe course of CF was evident in a number of patients with pancreatic sufficiency.

Conclusions

Physicians involved in care of patients with CF and in genetic counseling must be aware of the clinical heterogeneity of CF even in sib-pairs that, at the state of the art, is difficult to explain.

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0766-6) contains supplementary material, which is available to authorized users.

Endocrine Disorders in Cystic Fibrosis

Cystic fibrosis is frequently complicated by endocrine disorders. Diabetes can be expected to affect most with CF and pancreatic insufficiency and varies widely in age of onset, but early identification and treatment improve morbidity and mortality. Short stature can be exacerbated by relative delay of puberty and by use of inhaled corticosteroids. Bone disease in CF causes fragility fractures and should be assessed by monitoring bone mineral density and optimizing vitamin D status. Detecting and managing endocrine complications in CF can reduce morbidity and mortality in CF. These complications can be expected to become more common as the CF population ages.

Liver disease in cystic fibrosis

The survival of patients with cystic fibrosis (CF) has progressively increased over recent decades, largely attributable to early diagnosis through newborn screening and advances in nutritional and respiratory care. As the life expectancy of patients with CF has improved, non-respiratory complications such as liver disease have become increasingly recognized. Biochemical derangements of liver enzymes in CF are common and may be attributed to a number of specific hepatobiliary abnormalities. Among them, Cystic Fibrosis-associated Liver Disease (CFLD) is clinically the most significant hepatic complication and is believed to have a significant impact on morbidity and mortality. However, there remains much conjecture about the extent of the adverse prognostic implications that a diagnosis of CFLD has on clinical outcomes. The purpose of this review is to give an overview of the current knowledge regarding liver disease in children with CF.

Genetic modifiers of cystic fibrosis-related diabetes

Diabetes is a common age-dependent complication of cystic fibrosis (CF) that is strongly influenced by modifier genes. We conducted a genome-wide association study in 3,059 individuals with CF (644 with CF-related diabetes [CFRD]) and identified single nucleotide polymorphisms (SNPs) within and 5' to the SLC26A9 gene that associated with CFRD (hazard ratio [HR] 1.38; P = 3.6 × 10(-8)). Replication was demonstrated in 694 individuals (124 with CFRD) (HR, 1.47; P = 0.007), with combined analysis significant at P = 9.8 × 10(-10). SLC26A9 is an epithelial chloride/bicarbonate channel that can interact with the CF transmembrane regulator (CFTR), the protein mutated in CF. We also hypothesized that common SNPs associated with type 2 diabetes also might affect risk for CFRD. A previous association of CFRD with SNPs in TCF7L2 was replicated in this study (P = 0.004; combined analysis P = 3.8 × 10(-6)), and type 2 diabetes SNPs at or near CDKAL1, CDKN2A/B, and IGF2BP2 were associated with CFRD (P < 0.004). These five loci accounted for 8.3% of the phenotypic variance in CFRD onset and had a combined population-attributable risk of 68%. Diabetes is a highly prevalent complication of CF, for which susceptibility is determined in part by variants at SLC26A9 (which mediates processes proximate to the CF disease-causing gene) and at four susceptibility loci for type 2 diabetes in the general population.

Abnormal endocrine pancreas function at birth in cystic fibrosis ferrets

Diabetes is a common comorbidity in cystic fibrosis (CF) that worsens prognosis. The lack of an animal model for CF-related diabetes (CFRD) has made it difficult to dissect how the onset of pancreatic pathology influences the emergence of CFRD. We evaluated the structure and function of the neonatal CF endocrine pancreas using a new CFTR-knockout ferret model. Although CF kits are born with only mild exocrine pancreas disease, progressive exocrine and endocrine pancreatic loss during the first months of life was associated with pancreatic inflammation, spontaneous hyperglycemia, and glucose intolerance. Interestingly, prior to major exocrine pancreas disease, CF kits demonstrated significant abnormalities in blood glucose and insulin regulation, including diminished first-phase and accentuated peak insulin secretion in response to glucose, elevated peak glucose levels following glucose challenge, and variably elevated insulin and C-peptide levels in the nonfasted state. Although there was no difference in lobular insulin and glucagon expression between genotypes at birth, significant alterations in the frequencies of small and large islets were observed. Newborn cultured CF islets demonstrated dysregulated glucose-dependent insulin secretion in comparison to controls, suggesting intrinsic abnormalities in CF islets. These findings demonstrate that early abnormalities exist in the regulation of insulin secretion by the CF endocrine pancreas.

Intestinal obstruction syndromes in cystic fibrosis: meconium ileus, distal intestinal obstruction syndrome, and constipation

Meconium ileus at birth, distal intestinal obstruction syndrome (DIOS), and constipation are an interrelated group of intestinal obstruction syndromes with a variable severity of obstruction that occurs in cystic fibrosis patients. Long-term follow-up studies show that today meconium ileus is not a risk factor for impaired nutritional status, pulmonary function, or survival. DIOS and constipation are frequently seen in cystic fibrosis patients, especially later in life; genetic, dietary, and other associations have been explored. Diagnosis of DIOS is based on suggestive symptoms, with a right lower quadrant mass confirmed on abdominal radiography, whereas symptoms of constipation are milder and of longer standing. In DIOS, early aggressive laxative treatment with oral laxatives (polyethylene glycol) or intestinal lavage with balanced osmotic electrolyte solution and rehydration is required, which now makes the need for surgical interventions rare. Constipation can generally be well controlled with polyethylene glycol maintenance treatment.

Best practice guidance for the diagnosis and management of cystic fibrosis-associated liver disease

Approximately 5-10% of cystic fibrosis (CF) patients develop multilobular cirrhosis during the first decade of life. Most CF patients later develop signs of portal hypertension with complications, mainly variceal bleeding. Liver failure usually occurs later, after the paediatric age. Annual screening for liver disease is recommended to detect pre-symptomatic signs and initiate ursodeoxycholic acid therapy, which might halt disease progression. Liver disease should be considered if at least two of the following variables are present: abnormal physical examination, persistently abnormal liver function tests and pathological ultrasonography. If there is diagnostic doubt, a liver biopsy is indicated. All CF patients with liver disease need annual follow-up to evaluate the development of cirrhosis, portal hypertension or liver failure. Management should focus on nutrition, prevention of bleeding and variceal decompression. Deterioration of pulmonary function is an important consideration for liver transplantation, particularly in children with hepatic dysfunction or advanced portal hypertension.

A review of abdominal organ transplantation in cystic fibrosis

With advances in medical treatments, patients with CF are having improved quality of life and living longer. Although pulmonary disease is still the leading cause of morbidity and mortality, this longevity has allowed for the development of other organ dysfunction, mainly liver and pancreas. This review discusses the abdominal organ complications and the role of abdominal organ transplantation in CF. Liver failure and portal hypertension complications are the most common indicators for liver transplantation in CF, and five-yr survival for isolated liver transplantation is >80%. Deficiency of pancreatic enzymes is almost universal and up to 40% of patients with CF can develop insulin-dependent diabetes, although the role of pancreas transplantation is less clear and needs further research. Finally, the need for lung transplantation should always be assessed and considered in combination with liver transplantation on a case-by-case basis.

Ursodeoxycholic acid treatment in patients with cystic fibrosis at risk for liver disease

BACKGROUND

Meconium ileus has been detected as a risk factor for development of liver disease in cystic fibrosis, with influence on morbidity and mortality.

AIMS

To evaluate the effect of early treatment with ursodeoxycholic acid in patients with cystic fibrosis and meconium ileus to prevent chronic hepatic involvement and to explore the potential role of therapy on clinical outcomes.

METHODS

26 cystic fibrosis patients with meconium ileus (16 M, mean age 8,4 years, range 3,5-9) were assigned to two groups: group 1 (14 patients) treated early with ursodeoxycholic acid (UDCAe); group 2 (12 patients) treated with ursodeoxycholic acid at the onset of cystic fibrosis liver disease (UDCAd). Anthropometric data, pulmonary function tests, pancreatic status, complications such as diabetes, hepatic involvement and Pseudomonas aeruginosa colonisation were compared among groups.

RESULTS

A higher prevalence of cystic fibrosis chronic liver disease was observed in the UDCAd group with a statistically significant difference at 9 years of age (p<0.05). Chronic infection by P. aeruginosa was found in 7% of UDCAe and 33% of UDCAd (p<0.05). No differences were observed in nutritional status and other complications.

CONCLUSIONS

Early treatment with ursodeoxycholic acid may be beneficial in patients at risk of developing cystic fibrosis chronic liver disease such as those with meconium ileus. Multicentre studies should be encouraged to confirm these data.

Increased prevalence of risk factors for morbidity and mortality in the US Hispanic CF population

Hispanic ethnicity is an independent risk factor for increased morbidity and mortality in cystic fibrosis (CF) patients. In order to compare the prevalence of risk factors for morbidity and mortality between the Hispanic CF population and the non-Hispanic CF population, we performed a cross-sectional study of patients in the 2004 Cystic Fibrosis Foundation Patient Registry. Among 22,714 CF patients, 1,511 were identified as ethnic Hispanic. Hispanic patients were diagnosed earlier (2.8 vs. 3.3 years, P = 0.005) and acquired Pseudomonas aeruginosa at a younger age (6.6 years vs. 10 years, P < 0.001). FEV(1) was lower for Hispanic patients (81.5% vs. 87% predicted for those under 18 years old [P < 0.001] and 2.1 L vs. 2.3 L for those 18 years and older [P = 0.01]). Hispanic patients had similar or better nutritional status. Hispanic patients were more likely to be diagnosed with liver disease (OR 1.31 [1.1, 1.56]) but less likely to be diagnosed with depression (OR 0.53 [0.39, 0.68]), bone and joint disease (OR 0.55 [0.41, 0.71]), or CF-related diabetes (OR 0.53 [0.43, 0.62]). Hispanic patients had lower median income by zip code ($41,930 vs. $47,341; P < 0.001), a higher rate of government insurance (55.2% vs. 32.0%; P < 0.001), and greater percentage of mothers with less than a high school education (26.7% vs. 6.5%; P < 0.001). We conclude that there is an increased prevalence of important risk factors for morbidity and mortality in the Hispanic CF population.

Genetic modifiers play a substantial role in diabetes complicating cystic fibrosis

CONTEXT

Insulin-requiring diabetes affects 7-15% of teens and young adults, and more than 25% of older adults with cystic fibrosis (CF). Pancreatic exocrine disease caused by CF transmembrane conductance regulator (CFTR) dysfunction underlies the high rate of diabetes in CF patients; however, only a subset develops this complication, indicating that other factors are necessary.

OBJECTIVE

Our objective was to estimate the relative contribution of genetic and nongenetic modifiers to the development of diabetes in CF.

DESIGN/PATIENTS

This was a twin and sibling study involving 1366 individuals at 109 centers in the CF Twin and Sibling Study, from which were derived 68 monozygous twin pairs, 23 dizygous twin pairs, and 588 sibling pairs, all with CF.

MAIN OUTCOME MEASURE

Chronic, insulin-requiring diabetes in the setting of CF, as established using longitudinal clinical and biochemical data, was studied.

RESULTS

About 9% of this predominantly pediatric population (mean age = 15.8 yr) had diabetes. Key independent risk factors identified by regression modeling included having a twin or sibling with CF and diabetes, increasing age, pancreatic exocrine insufficiency or two mutations causing severe CFTR dysfunction, decreased lung function or decreased body mass index, and longer duration of glucocorticoid treatment. The concordance rate for diabetes was substantially higher in monozygous twins (0.73) than in dizygous twins and siblings with CF (0.18; P = 0.002). Heritability was estimated as near one (95% confidence interval 0.42-1.0).

CONCLUSIONS

Diabetes is a frequent complication of CF that is associated with worse outcomes. Although a nongenetic factor (steroid treatment) contributes to risk, genetic modifiers (i.e. genes other than CFTR) are the primary cause of diabetes in CF.

Liver disease in cystic fibrosis

PURPOSE OF REVIEW

This review highlights recent developments in liver disease associated with cystic fibrosis.

RECENT FINDINGS

The broad spectrum of hepatobiliary problems in cystic fibrosis includes specific alterations ascribable to the underlying defect as well as lesions of iatrogenic origin or that reflect the effects of a disease process occurring outside the liver. Focal biliary cirrhosis, resulting from biliary obstruction and progressive periportal fibrosis, is the most clinically relevant problem, because extension of the initially focal fibrogenic process may lead to multilobular biliary cirrhosis, portal hypertension and eventually liver failure. Cystic fibrosis associated liver disease is presently classified among genetic cholangiopathies and results from lack or dysfunction of the cystic fibrosis transmembrane regulator at the apical membrane of bile duct cells. Major advances have been achieved regarding characterization of natural history, risk factors, diagnostic modalities and treatment options.

SUMMARY

Liver disease is a relatively frequent and early complication of cystic fibrosis. The pathogenesis is apparently multifactorial, with contributions from environmental and genetic determinants. Its impact on quality of life and survival will increase in future years, and its early detection and treatment will become increasingly important issues. Ursodeoxycholic acid is the only treatment currently available, but novel therapeutic options are being evaluated.