Prevalence of Non-alcoholic Fatty Liver Disease in Patients With Chronic Kidney Disease in Assiut University Hospitals

The aim of our study is:

1. The early detection of NAFLD in CKD patients with different stages (stage I to IV) to avoid progression to liver fibrosis.
2. Evaluation of the relationship between the severity of fatty liver in NAFLD assessed by liver enzymes, biochemical markers, ultrasonography and grades of Fibroscan with CKD staging, eGFR and proteinuria.

Chronic kidney disease (CKD) is defined as presence of reduced glomerular filtration rate (GFR) \< 60 ml/min/ 1.73 m2 and/or evidence of kidney damage (usually indicated by albuminuria or proteinuria) for \> 3 months or more irrespective of cause . CKD stages are classified according to the National Kidney Foundation in to five stages according to estimated GFR .

The prevalence of CKD is continuously rising in concert with the rising epidemic of its risk factors including ageing, diabetes, obesity, metabolic syndrome, smoking, and hypertension .

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases in Western countries. It encompasses a spectrum of conditions with lipid deposition in hepatocytes, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH).

It is defined as fatty liver with inflammation and hepatocelullar injury with or without fibrosis, advanced fibrosis and cirrhosis. Metabolic syndrome with its clinical traits is highly prevalent in patients with NAFLD .

Preliminary data suggest an association between CKD and NAFLD .reported that the prevalence of CKD was significantly higher in patients with NASH compared to patients without NASH.

Moreover, Yassui k documented the presence of moderately decreased eGFR and high frequency of micro-albuminuria in patients with biopsy proven NASH.

The diagnosis of NAFLD/NASH is based on the gold standard of liver biopsy or less reliably on serum liver enzymes or ultrasound imaging. However, liver biopsy has its limitations: apart from being an invasive procedure, connected with serious complications .

Many non-invasive procedures have been intensively applied to detect hepatic steatosis and fibrosis. The Controlled Attenuation Parameter (CAP) can using transient elastography (TE) (Fibroscan®) permits to efficiently separate different grades of severity of steatosis. CAP is based on the properties of ultrasonic signals acquired by the Fibroscan®. It allows to simultaneously measure liver stiffness and CAP in the same liver volume.

The volume used for the measurement by the Fibroscan® is 200 times larger than that of a liver biopsy specimen. Therefore the Fibroscan® is used more and more in clinical practice .

Many biochemical markers can be used for diagnosis of NAFLD such as tissue inhibitor of metalloproteinase 1 (TIMP1), aminoterminal peptide of procollagen III (P3NP) .

Up till now, the relationship between NAFLD and CKD is still poorly understood and under discussed.

Eligibility Criteria:
Inclusion Criteria:

- Eighty CKD patients with different stages (stage I to IV) according to the National Kidney Foundation are recruited from inpatients of renal unit in internal medicine department, Assuit university hospitals. Their GFR will assessed by using CKD EPI equation measured as GFR=166 x(s cr/0.7)-1.209X(0.993)age if female, and GFR=163X(s cr/0.9)-1.209x(0.993)age if male. (Andrews et al 2009).

CKD staging according to GFR by CKD EPI is:

* Stage1 in which GFR\>90 mil/min but evidence of kidney damage.
* Stage 2 GFR 60-89 mil/min.
* Stage 3 GFR 30-95 mil/min.
* Stage 4 GFR 15-29 mil/min.
* Stage 5 GFR\<15 mil/min. The patients will be enrolled from October 2020 to October 2021.

Exclusion Criteria:

* 1- All Patients with positive hepatitis C virus antibodies. 2- All Patients with positive hepatitis B surface antigen. 3- Congested liver. 4- Drug induced hepatosteatosis (INH, estrogens, methotrexate, steroids, amiodarone, etc.).

  5- Autoimmune liver diseases. 6- Metabolic liver diseases. 7- Alcoholic liver disease. 8- Malignancy. 9- ESRD (stage V) on hemodialysis. 10- Obesity overweight BMI \> 30. 11- Metabolic syndrome. 12- Type II DM.