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\begin{document}

\title{CLINICAL AND GENETIC RISK FACTORS FOR CYSTIC FIBROSIS-RELATED LIVER
DISEASE IN EGYPTIAN CF CHILDREN: A SINGLE-CENTER EXPERIENCE}



\author[1]{Samya Nasr}%
\author[2]{Amel El-Faramawy}%
\author[2]{Mohamed Al Emam MS}%
\author[2]{Heba Moustafa Hamza}%
\affil[1]{University of Michigan Department of Pediatrics}%
\affil[2]{Ain Shams University Faculty of Medicine}%


\vspace{-1em}



  
  \date{May 18, 2024}


\begingroup
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\selectlanguage{english}
\begin{abstract}
\textbf{Background:} Cystic fibrosis (CF) is an autosomal recessive
disease affecting multiple organ systems, including the liver, leading
to cystic fibrosis-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). The present 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 and the comparison of CFLD in Egyptian
and non-Egyptian CF patients will be done. \textbf{Methods:} The current
cross-sectional study included 50 CF cases 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. All patients' caregivers provided informed consent.
Additionally, all subjects underwent detailed history taking, laboratory
investigations, clinical assessment, and pelviabdominal ultrasound for
evaluation of hepatic involvement. \textbf{Results:} Male sex, severe
genetic mutation (class I and II), long duration, and early onset of the
disease were independent risk factors for CFLD development. In addition,
pancreatic insufficiency, as well as meconium ileus history, were
predictors of CFLD. Diabetes mellitus and severe lung disease were
proven to significantly elevate the risk of CFLD development.
\textbf{Conclusion:} CFLD is not uncommon in Egyptian CF patients as
one-third of the patients were found to have liver affection. CF
patients with multiple risk factors are at increased risk of developing
liver disease.%
\end{abstract}%



\sloppy


\textbf{Introduction}

CF is a systemic disease affecting multi-organs. As a result of progress
in the treatment of CF, life expectancy has been steadily increasing,
leading to increased recognition of other organ involvement, including
CFLD.\textsuperscript{1} CFLD is triggered by~CFTR gene mutation, which
is expressed in cholangiocytes and regulates the exchange
of~transmembrane chlorides, resulting in a modification in the
alkalinity as well as~hydration of~the bile
composition.\textsuperscript{2} Even though CF often impacts the
airways, nearly 10-15 percent of pwCF have CFLD to some
degree.\textsuperscript{3} In~young adults as well as children, the
imaging (ultrasonography), clinical or~biochemical~CFLD
prevalence~ranges from 2\% to 37\%.\textsuperscript{4}

CFLD is now estimated to be the third most common cause of~mortality
among CF cases, following organ transplantation complications as well as
lung disease. CFLD clinical picture may vary, from mild asymptomatic
hypertransaminasemia to cirrhosis.

The pathomechanism of CFLD is related to alternations in bile flow as
well as retention and composition of toxins and hydrophobic bile acids
damaging the biliary epithelium. The clinical progression of this
impairment is gradual but progressive .\textsuperscript{5}

In infants, CFLD can be in the form of cholestasis which can be
associated with parenteral nutrition and meconium
ileus.\textsuperscript{6} Although CFLD early diagnosis is critical
since clinical symptoms manifest only after hepatobiliary system damage
has already been in progress.\textsuperscript{7} Nevertheless, diagnosis
is difficult owing to the usual asymptomatic presentation as well as the
lack of specific diagnostic tools.\textsuperscript{8}

It has been speculated that the incidence of CFLD in Egyptian CF cases
is more elevated compared to the Western World, causes leading to this
difference have not been clear. This study aimed to identify the
incidence of CFLD, a predictive factor in Egyptian CF children and
compare this to other pwCF globally.

\textbf{Methods}

The current cross-sectional study included 50 CF cases from the
Children`s Hospital's Pediatric Pulmonology Clinic, Ain Shams
University, Cairo, Egypt, and was approved by the hospital ethics
committee. Patients' guardians/parents provided informed consent prior
to starting the study.

Patients [?]16 years of age were diagnosed with CF through a positive
sweat chloride test, and/ or two diseases resulting in the mutation of
CF transmembrane conductance regulator (CFTR) were enrolled in this
study. Patients were excluded if they have been on hepatotoxic drugs as
antifungals and anti-tuberculous drugs; or having associated liver
disease (e.g., Chronic viral hepatitis).

The following were collected from each patient: medical history
including age, sex and age at diagnosis, past medical history, family
history and socioeconomic histories, clinical assessment of pulmonary,
hepatobiliary, and gastrointestinal symptoms, laboratory testing
including complete blood count (neutrophils, lymphocytes, white blood
cell count, hemoglobin, and platelets), liver enzymes as ALT, AST, and
albumin, coagulation parameters (PT, PTT, INR). In addition,
pelvic-abdominal ultrasound was done for evaluation of the size and
echogenicity of the liver, size of the spleen, presence or absence of
ascites, portal vein, common bile duct, and gall bladder sludge or
stones. Observation of a bright echo pattern of the liver on ultrasound
is commonly considered a sign of hepatic steatosis.

A full clinical examination was done including vital signs, weight,
height, as well as body mass index (BMI), chest and abdominal
examination. Shwachman-Kulczycki score was utilized for assessing CF
disease severity based on four different parameters: radiological
findings, nutrition status, physical examination, and general activity.
Each characteristic is assigned a value between 5 (severely impaired)
and 25 (normal), resulting in a total score that is classified as
excellent (86-100), good (71-85), mild (56-70), moderate (41-55) or
severe (\textless{}40).\textsuperscript{9}

\emph{Statistical Analysis}

Data collection, revision, coding, and entry were done utilizing the
23\textsuperscript{rd} version of the (IBM\textsuperscript{(R)} SPSS).
Quantitative data were expressed as ranges, standard deviations, as well
as mean, standard deviations, and ranges, whereas qualitative variables
were expressed as percentages and numbers.

Comparing groups in terms of qualitative data was performed utilizing
the Fisher exact test or Chi-square test. The Independent t-test was
used for parametric distribution, while the Mann-Whitney test was used
for nonparametric distribution. Multivariate logistic regression
analysis was utilized for the strength of the association between risk
factors for CFLD. Moreover, the confidence interval was determined at 95
percent, while the accepted error margin was at 5 percent. The
significance level was determined at p-value \textless{} 0.05 and
considered highly significant if p \textless{} 0.01.

\textbf{Results}

This study included 50 cases, sweat test was 73-159 mmol/L, 80\% of the
patients had productive cough, 46\% had dyspnea, 90\% had steatorrhea,
20\% had CFRD and 62\% of patients had BMI at the
\textless{}3\textsuperscript{rd}\%. There was a positive family history
of CF in 32\% of the total patient population (16 patients). Nineteen
patients (38\% ) out of the 50 patients were diagnosed with CFLD (Table
1). Seven out 19 (37\%) showed liver abnormality through abnormal
biochemical labs and ultrasound abnormalities while 12 (63\%) had
clinical abnormalities, in addition. Compared the CFLD cohort (19
patients) to the non-CFLD cohort (31 patients), Liver involvement was
significantly correlated with male sex, early onset of disease, longer
duration of illness, and higher mortality rate with
p-value\textbf{\textless{}} 0.05, while there was no substantial
difference between both groups with respect to consanguinity with
p-value 0.34. It was noted that sweat chloride test levels were higher
in the CFLD group (Table 1).

There were differences in genetic mutations between both cohorts, with
class I and II mutations more frequent in the CFLD cohort with a p-value
\textless{}0.05, while class V mutation was more prevalent in the
non-CFLD cohort with a p-value \textless{}0.05. F508del homozygous was
the most common mutation in both groups representing 64.3\% of the CFLD
cases and 33.3\% of the non- CFLD cases (Table 2).

Table 3 shows a statistically significant correlation between CFLD and
gender, duration of illness \textgreater{} 5 years, weight and height
\textless{} 5\textsuperscript{th} percentile, early onset of the disease
[?] 9 months, clinically severe disease, class I or II mutations,
non-compliance to pancreatic enzyme replacement therapy as well as
fat-soluble vitamins while there was no statistically significant
association with Neonatal Intensive Care Unit (NICU) admission due to
meconium ileus.

Using Shwachman- Kulczycki score, there was significantly severe disease
involvement in CFLD cases (63.2\%) while in non-CFLD cases the degree of
severe disease was only 16.1\% with P-value \textless{} 0.01. Most
non-CFLD cases presented with mild to moderate disease.

\textbf{Discussion}

The improved CF management in high income countries has led to an
increased life expectancy in CF cases. Consequently, as pwCF get older,
a substantial liver dysfunction emerges, which complicates the disease
with incidence of 10-15\%.\textsuperscript{10} The occurance of CF in a
prospective study was found to be 2.5 per 100 patient-years during early
life years, with an increase in the second
decade.\textsuperscript{11}Hepatobiliary involvement was reported in
4-10.9 percent of Middle Eastern CF cases.\textsuperscript{12,13} In a
previous study of CF cases in Egypt, the CFLD rate was found to be more
elevated compared to the US population.\textsuperscript{12} In the
current study, the frequency of liver disease in CF patients was 38\%,
significantly higher than previously reported in the Middle Eastern
population. This study revealed that the male sex is a significant risk
factor associated with CFLD, which was reported previously in 2
case-control studies in several western
countries.\textsuperscript{13,14}

A large cohort study was done on 177 pwCF (aged between one month and 23
years) and found that liver disease occurred before puberty in all
female patients, and the incidence increased up to 18\% by the age of
eleven years, but in male patients, the incidence increased from 25\% by
the age of eleven up to 42\% by the age of
eighteen.\textsuperscript{11}That could be due to endocrine factors
involved in CFLD development with the estrogen and its receptors
substantially contributing to the modulation of secretory and
proliferative activities of the intrahepatic biliary epithelium due to
liver damage.\textsuperscript{11} This incidence was similar to what we
found in our study and it was significantly higher than previously
reported in other studies.

In a retrospective analysis of data from 561 pwCF in Canada, Stonebraker
et al. found that mutations, as well as male gender related to severe
phenotype, increased the progression of severe liver
disease.\textsuperscript{15} This study had illustrated risk factors
including male sex, and class I-III mutations, which is related to
meconium ileus as well as pancreatic insufficiency at
birth.\textsuperscript{15} In a prospective study, F508del was detected
in 51-55 percent of CFLD cases.\textsuperscript{11} That was similar to
what was found in our study where 64\% of the patients with CFLD had
F508del and that was statistically significant compared to patients that
didn't have CFLD (33\%).

In addition, the young age at diagnosis and the longer duration of the
disease, the more susceptibility to CFLD development. This is in
agreement with a study, in which the median age of onset of CFLD was
between 6-8 months.\textsuperscript{16} In a study regarding risk
factors leading to CFLD in a large-scale cohort of patients in France
concluded that male sex and long duration of illness are significant
risk factors for developing CFLD, they also found that CFLD occurrence
elevated by 1-2 percent every year from birth until the age of 25 years
of age.\textsuperscript{17} Also, Fagundes et al. and Efrati et al. in a
study including one hundred and fifty pwCF between 1975 and 2000 in the
National Cystic Fibrosis Center in Israel revealed that the early onset
of CF and long duration are significant risk factors for developing
CFLD.\textsuperscript{18,19}

CFLD often manifests during the two decades of life. The majority of CF
children tend to develop a degree of steatosis. CF-related multi-lobular
cirrhosis or focal biliary cirrhosis occur in children and adolescent,
but major biliary involvement resembling sclerosing cholangitis is more
common in adults. In severe CFLD, portal hypertension, particularly
non-cirrhotic portal hypertension, might cause variceal
bleeding.\textsuperscript{20}

It has been reported that severe CFLD is life-threatening because it is
associated with the progression of portal hypertension, and worsening of
the respiratory status and liver transplantation might be
indicated.\textsuperscript{21} In our CFLD patients, 89\% of the
patients had productive cough and 46\% had dyspnea. Steatorrhea was
present in 90\% and CF-assocaited diabetes CFRD was present in 37\% of
patients. In addition to 68\% of patients had hepatomegaly, 16\% had
splenomegaly, 57\% had abdominal distention, 2 patients had gall bladder
stones and 1 had ascites. None of the patients had portal hypertension,
biliary dilation, or jaundice. In accordance with these findings,
Colombo et al. observed hepatomegaly in 6--30\% of
cases,\textsuperscript{21} even though our patients had higher rate of
hepatomegaly (68\%).

In our patients with CFLD, abdominal ultrasound revealed hepatomegaly in
28\%, hepatic steatosis in 24\%, Cholelithiasis in 4\% (males), ascites
in 2\%, and splenomegaly in 16\%. That was similar to the finding in a
study, which revealed hepatic steatosis in 20--60\% and Cholelithiasis
was in 1--10\% of the studied patients in a study including a group of
124 children with an average age of 5.4 years in the United
Kingdom.\textsuperscript{22} A retrospective review of sequential
abdominal ultrasound reported that 11.9\% of the patients had
splenomegaly, seven cases (4.2\%) had frank cirrhotic changes on
ultrasound criteria, and eight cases (4.8\%) experienced gall bladder
stones with male predominance in this group (6/8).\textsuperscript{23}

History of meconium ileus was reported in the CFLD cases representing
26.3\% than the non-CFLD cases representing 6.5\%. While Bock et al.
revealed that meconium ileus was reported in 20\% of the
cases.\textsuperscript{24} Colombo et al. reported that cases with a
history of meconium ileus were five times more prone to develop CFLD
compared to cases without.\textsuperscript{11} The development of liver
disease in intestinal obstruction cases could be due to inspissated
bowel that leads to biliary secretion that plugs the bile ductule
leading to liver damage. One-fourth of patients in this study developed
liver disease.

This study showed that CFRD is a major risk factor associated with CFLD
development as 37\% of patients were diagnosed with CFRD. That was
similar to a study that reported, that 32\% of patients with CFLD had
CFRD.\textsuperscript{25} In another study, CFRD was a considerable risk
factor for CFLD development in Italian CF
Registry.\textsuperscript{26}In addition\textbf{,} this study showed
that pancreatic insufficiency, meconium ileus history, and younger age
at diagnosis, were all related to severe~CFTR~mutation classes, and were
proven as risk factors for CFLD development.\textsuperscript{26} Another
study reported that severe mutations (classes I, II, or III) manifesting
with elevated mortality as well as morbidity are substantially related
to younger age (\textless{}1 year), meconium ileus, as well as
pancreatic insufficiency at diagnosis, and liver
affection.\textsuperscript{27} Another study reported that mild CFTR
mutations (class IV and class V) are uncommon in individuals with
CFLD.\textsuperscript{28} Our study revealed that severe mutations
including classes I and II was a significant risk factor associated with
the development of CFLD. Furthermore, F508del is the most common
mutation representing 64.3\% of the studied patients. That was similar
to previous reports, of correlation between CFLD and severe genetic
mutations (class I and II) in retrospective studies to investigate
potential risk factors for developing CFLD in the
Netherlands.\textsuperscript{11,19,29}

In this study, CFLD was associated with severe CF disease as per
Shwachman score (63.2\% of the CFLD group had severe CF disease compared
to 16.1\% in the non-CFLD group). Patients with CFLD had frequent
hospital admissions and impaired growth and nutrition. Similarly, it was
reported in some studies that, children with established CFLD suffer
from impaired nutrition and growth, severe lung disease with worse
pulmonary function, as well as altered body composition
.\textsuperscript{26,30} In another study, similar findings were
noted.\textsuperscript{13}

Early~liver disease diagnosis~is a significant problem for the clinical
management of those cases. Usually, liver-associated symptoms might be
undetectable until cirrhosis and portal hypertension are
developed.\textsuperscript{21} All our CFLD patients were treated with
ursodeoxycholic acid. Nevertheless, Cochrane Reviews have shown that the
effectiveness of ursodeoxycholic acid has not been proven
clearly.\textsuperscript{31}

As there is no efficient medication to treat or inhibit the development
of cirrhosis, portal hypertension, or fibrosis in CFLD, its management
should be carried out by a multidisciplinary team and is mostly
supportive. Liver transplantation (LT) might be recommended for CFLD
cases with intractable complications of portal hypertension or end-stage
liver disease since it provides substantial survival advantages.
However, LT does not always enhance long-term pulmonary prognosis.
Therefore, subjects~with~liver disease, as well as combined lung
disease,~ may undergo combined lung and liver transplantation
(CLLT).\textsuperscript{32}

This study revealed in addition, that non-adherence to pancreatic enzyme
replacement therapy represent 78.9\% of the CFLD group while
representing 38.7\% of the non- CFLD group. In addition, non-adherence
to fat-soluble vitamins represents 47.4\% of CFLD group vs. 16.1\% in
the non-CFLD group. These findings could be factors in developing CFLD,
as well.

\textbf{Conclusion}

CFLD is not uncommon in CF as one third of the CF patients were found to
have liver involvement in this Egyptian patient population diagnosed
clinically, biochemically and/or by ultrasound. CFLD incidence was
elevated in male individuals, patients with duration of illness
\textgreater{} 5 years, patients with weight and height \textless{} 5th
percentile, early onset of disease before the age of 9 months, history
of meconium ileus, patients not adherent to fat-soluble vitamins as well
as pancreatic enzyme replacements, patients with severe CF disease and
patients with class I and II genetic mutation. More studies from low-
and middle-income countries like Egypt, are needed to help understand
the nature of the disease, improve patients' quality of life, improve
survival and help improve the disease outcome globally.

\textbf{References}

1. Kobelska-Dubiel N, Klincewicz B, Cichy W. Liver disease in cystic
fibrosis. Prz Gastroenterol 2014;9(3):136--141.

2. Betapudi B, Aleem A, Kothadia JP. Cystic Fibrosis And Liver Disease.
StatPearls Publishing; 2020.

3. Paranjape SM, Mogayzel PJ. Cystic fibrosis in the era of precision
medicine. Paediatr Respir Rev 2018;25:64--72.

4. Wilschanski M, Miller LL, Shoseyov D, Blau H, Rivlin J, Aviram M,
Cohen M, Armoni S, Yaakov Y, Pugatch T, et al. Chronic ataluren (PTC124)
treatment of nonsense mutation cystic fibrosis. Eur Respir J
2011;38(1):59--69.

5. Sakiani S, Kleiner DE, Heller T, Koh C. Hepatic Manifestations of
Cystic Fibrosis. Clin Liver Dis 2019;23(2):263--277.

6. Minagawa N, Nagata J, Shibao K, Masyuk AI, Gomes DA, Rodrigues MA,
Lesage G, Akiba Y, Kaunitz JD, Ehrlich BE, et al. Cyclic AMP Regulates
Bicarbonate Secretion in Cholangiocytes Through Release of ATP Into
Bile. Gastroenterology 2007;133(5):1592--1602.

7. Siano M, De Gregorio F, Boggia B, Sepe A, Ferri P, Buonpensiero P, Di
Pasqua A, Raia V. Ursodeoxycholic acid treatment in patients with cystic
fibrosis at risk for liver disease. Dig Liver Dis 2010;42(6):428--431.

8. Staufer K, Halilbasic E, Trauner M, Kazemi-Shirazi L. Cystic fibrosis
related liver disease-another black box in hepatology. Int J Mol Sci
2014;15(8):13529--13549.

9. Stollar F, Adde FV, Cunha MT, Leone C, Rodrigues JC.
Shwachman-Kulczycki score still useful to monitor cystic fibrosis
severity. Clinics 2011;66(6):979--983.

10. Keogh RH, Szczesniak R, Taylor-Robinson D, Bilton D. Up-to-date and
projected estimates of survival for people with cystic fibrosis using
baseline characteristics: A longitudinal study using UK patient registry
data. J Cyst Fibros 2018;17(2):218--227.

11. Colombo C, Battezzati PM, Crosignani A, Morabito A, Costantini D,
Padoan R, Giunta A. Liver disease in cystic fibrosis: A prospective
study on incidence, risk factors, and outcome. Hepatology
2002;36(6):1374--1382.

12. Al-Mahroos F. Cystic fibrosis in Bahrain incidence, phenotype, and
outcome. J Trop Pediatr 1998;44(1):35--39.

13. Rawashdeh M, Manal H. Cystic fibrosis in Arabs: A prototype from
Jordan. Ann Trop Paediatr 2000;20(4):283--285.

14. Naguib ML, Schrijver I, Gardner P, Pique LM, Doss SS, Abu Zekry MA,
Aziz M, Nasr SZ. Cystic fibrosis detection in high-risk Egyptian
children and CFTR mutation analysis. J Cyst Fibros 2007;6(2):111--116.

15. Stonebraker JR, Ooi CY, Pace RG, Corvol H, Knowles MR, Durie PR,
Ling SC. Features of Severe Liver Disease With Portal Hypertension in
Patients With Cystic Fibrosis. Clin Gastroenterol Hepatol
2016;14(8):1207-1215.e3.

16. Sharma DG. Cystic Fibrosis Treatment \& Management: Approach
Considerations, Diet and Exercise, Surgical Management of Complications.
Medscape Med News 2022.

17. Bo\selectlanguage{ngerman}ëlle PY, Debray D, Guillot L, Clement A, Corvol H. Cystic Fibrosis
Liver Disease: Outcomes and Risk Factors in a Large Cohort of French
Patients. Hepatology 2019;69(4):1648--1656.

18. Fagundes EDT, Roquete ML V., Penna FJ, Reis FJC, Goulart EMA, Duque
CG. Fatores de risco da hepatopatia da fibrose cística. J Pediatr (Rio
J) 2005;81(6):478--484.

19. Efrati O, Barak A, Modan-Moses D, Augarten A, Vilozni D, Katznelson
D, Szeinberg A, Yahav J, Bujanover Y. Liver cirrhosis and portal
hypertension in cystic fibrosis. Eur J Gastroenterol Hepatol
2003;15(10).

20. Valamparampil JJ, Gupte GL. Cystic fibrosis associated liver disease
in children. World J Hepatol 2021;13(11):1727--1742.

21. Fiorotto R, Strazzabosco M. Pathophysiology of Cystic Fibrosis Liver
Disease: A Channelopathy Leading to Alterations in Innate Immunity and
in Microbiota. Cmgh 2019;8(2):197--207.

22. Diwakar V, Pearson L, Beath S. Liver disease in children with cystic
fibrosis. Paediatr Respir Rev 2001;2(4):340--349.

23. Williams SM, Goodman R, Thomson A, Mchugh K, Lindsell DRM.
Ultrasound evaluation of liver disease in cystic fibrosis as part of an
annual assessment clinic: A 9-year review. Clin Radiol
2002;57(5):365--370.

24. Bock JM, Schien M, Fischer C, Naehrlich L, Kaeding M,
Guntinas-Lichius O, Gerber A, Arnold C, Mainz JG. Importance to question
sinonasal symptoms and to perform rhinoscopy and rhinomanometry in
cystic fibrosis patients. Pediatr Pulmonol 2017;52(2):167--174.

25. Nährlich L, Burkhart M, Wiese Helfen Forschen Heilen B. Deutsches
Mukoviszidose. 2015.

26. Minicucci L, Lorini R, Giannattasio A, Colombo C, Iapichino L, Reali
MF, Padoan R, Calevo MG, Casciaro R, De Alessandri A, et al. Liver
disease as risk factor for cystic fibrosis-related diabetes development.
Acta Paediatr Int J Paediatr 2007;96(5):736--739.

27. Farrell PM, Rosenstein BJ, White TB, Accurso FJ, Castellani C,
Cutting GR, Durie PR, LeGrys VA, Massie J, Parad RB, et al. Guidelines
for Diagnosis of Cystic Fibrosis in Newborns through Older Adults:
Cystic Fibrosis Foundation Consensus Report. J Pediatr
2008;153(2):S4--S14.

28. Bartlett JR, Friedman KJ, Ling SC, Pace RG, Bell SC, Bourke B,
Castaldo G, Castellani C, Cipolli M, Colombo C, et al. Genetic modifiers
of liver disease in cystic fibrosis. Jama 2009;302(10):1076--1083.

29. Slieker MG, Deckers-Kocken JM, Uiterwaal CSPM, Van Der Ent CK,
Houwen RHJ, Colombo C, Battezzati PM, Crosignani A. Risk factors for the
development of cystic fibrosis related liver disease {[}2{]} (multiple
letters). Hepatology 2003;38(3):775--776.

30. Rowland M, Bourke B. Liver disease in cystic fibrosis. Curr Opin
Pulm Med 2011;17(6):461--466.

31. Cheng K, Ashby D, Smyth RL. Ursodeoxycholic acid for cystic
fibrosis-related liver disease. Cochrane Database Syst Rev 2017;2017(9).

32. Freeman AJ, Sellers ZM, Mazariegos G, Kelly A, Saiman L, Mallory G,
Ling SC, Narkewicz MR, Leung DH. A Multidisciplinary Approach to
Pretransplant and Posttransplant Management of Cystic
Fibrosis--Associated Liver Disease. Liver Transplant
2019;25(4):640--657.

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