Is fatty liver essentially a heart disease?

It licks the liver but bites the heart
NAFLD with its advanced stages are the most frequent indication needing liver transplantation.
NAFLD with its advanced stages are the most frequent indication needing liver transplantation.

Liver is a very important body organ that is responsible for a variety of critical functions that help and support metabolism, immunity, digestion, detoxification, production of proteins including clotting factors and vitamin storage besides excretion of bilirubin, cholesterol, hormones and drugs. It is the body’s largest solid organ weighing around 1.5 Kgs in an adult.

Fatty liver is a common condition. Alcohol consumption is a well-known cause of fatty liver in persons who consume regular alcoholic beverages. The breakdown of alcohol occurs in liver cells and its degradation products are damaging and injure them by way of replacement with fats and also inflammatory cells. As this injury becomes repetitive it can advance into alcoholic hepatitis and finally cirrhosis of liver.

Non-Alcoholic Fatty Liver Disease (NAFLD):

Healthy liver should contain no or very little fat. If it is more than 5%, it is considered high and constitutes what is known as NAFLD.  It is a very common condition seen worldwide. According to a large meta-analysis from India reported in 2022 by Shalimar and others, it was present in 38.6% of the adult and 35.6% of children’s population.

Stages of NAFLD and Diagnosis: Stage 1. simple fatty liver or steatosis, Stage 2. Non-alcoholic steatohepatitis (NASH), Stage3, Fibrosis, Stage 4, Cirrhosis. 

An abdominal ultrasound is the most easily available diagnostic test and NAFLD is often diagnosed incidentally.

CT scan or MRI scans have no additional ability in diagnosis and cannot differentiate NASH from NAFLD. Liver elastography or Fibro Scan is a type of liver elastography which measures liver stiffness/ hardness of the fatty liver. Liver biopsy is the gold standard test to diagnose NASH.

NAFLD with its advanced stages are the most frequent indication needing liver transplantation.

NAFLD and Cardiovascular Disease: It is becoming increasingly known that there is a very common linkage of fatty liver disease with cardio-vascular diseases. A part of it is that there is a frequent association of obesity, high blood pressure, diabetes, high lipid levels and obstructive sleep apnoea. Detailed analysis has also shown an independent relationship. NASH has a 6 times higher risk for angina, heart attacks and related events as compared to liver cell failure. It is therefore suggested by several experts to rename NAFLD as metabolically associated fatty liver disease (MAFLD). This is especially true if BMI is > 23kg/m2 along type 2 diabetes mellitus or association with at least 2 components of metabolic disorders. Overweight and high lipid levels / high BP.

It is clear that NAFLD and cardiovascular diseases share several common risk factors; Obesity, dyslipidaemia, physical inactivity. Insulin resistance is common in both NAFLD with endothelial dysfunction and atherosclerotic CV disease. Although patients with NAFLD are usually overweight but it has been seen CV disease is frequently seen even in individuals with lean NAFLD (which can constitute up to 10-20% individuals).

NAFLD and Heart Failure (HF): This association has recently been observed and reported from USA. The association is independent of above-mentioned heart disease like angina and heart attacks. Heart failure has a high mortality and only 30 to 40 % patients survive beyond 5 years. The kind of heart failure which is seen is most often associated with preserved left ventricular ejection fraction (Hfpef). Its recognition is easy if blood biomarker like nt pro BNP is measured     in those patients who complain of getting out of breath. Unlike in the past, we have drugs to treat this entity with gratifying results.

NAFLD Patients need Cardiac Evaluation:

It is thus imperative that NAFLD even earlier stages need to be taken seriously. All of them need to have a complete physical examination consisting of calculation of BMI, BP measurement routine blood biochemistry including Hs CRP and simple investigations like ECG, Echo and an exercise stress test. An early diagnosis leads to early management so as to prevent a catastrophic complication like a heart attack, a stroke or sudden death. 

Management of NAFLD with or without CV Disease:

Life style modification leading to weight loss, calorie reduction, exercise and healthy food intake is the most cost-effective and efficacious method. Use of mono-unsaturated fatty acids with rich sources like olive, peanut and canola oils. A loss of 5% and more of weight starts reducing the fat content of fatty liver, the histological changes start regressing by 7-9% loss and fibrotic changes start reversing by more than 10% weight loss.

Besides treating the accompaniments like diabetes, high BP, high cholesterol, there are some drugs which are recommended by the NAFLD guidelines. These are Vitamin E in confirmed cases of NASH (without diabetes and cirrhosis) and pioglitazone (in biopsy confirmed cases of NASH). Both these agents have their problems like haemorrhagic strokes and increased prostate cancer with innocuous looking Vit E and thus should be taken under medical supervision only. Pioglitazone can be associated with weight gain, osteoporosis, heart failure and bladder cancer and should be used with caution only in selected cases.

The 2 group of drugs which seem to be very promising are GLP1 analogues like liraglutide or semaglutide and SGLT2 inhibitors like dapagliflozin and empagliflozin. The clinical trials with these agents for the indication of NASH are in progress. These agents are however available in our country and could be used as off label indications on physicians’ discretion as a compassionate measure.

Healthy life style modifications with diet exercise and losing weight by around 10% is the most trusted way to make liver and its linkage with heart healthier.

Prof Upendra Kaul, Chairman Cardiology and Dean Academics and Research Batra Hospital and Medical Research Center, is Founder Director Gauri Kaul Foundation

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