Fatty liver, NAFLD and Obesity - #obsmuk blog by Dr Dina Mansour
Non-alcoholic fatty liver disease (NAFLD) is accumulation of
fat in the liver. NAFLD is part of the
metabolic syndrome, characterised by diabetes or pre-diabetes (insulin
resistance), affected by overweight or
obesity, hypertension and hyperlipidaemia, and is more common in people with
these other features. There is a
spectrum of disease ranging from just fat in the liver (steatosis) to a more
progressive form of the disease, non-alcoholic steatohepatitis (NASH) – this is
where the fat in the liver is associated with inflammation and liver
damage. Over time this can lead to
fibrosis or scarring. Progressive
fibrosis leads to cirrhosis with all its associated complications -jaundice,
ascites, encephalopathy (confusion), varices (mainly in the oesophagus/gullet) and
hepatocellular carcinoma (liver cancer).
NAFLD affects approximately 30% of the population, 70% of people
affected by type 2 diabetes and over 90% of patients with a BMI of over
30. Steatohepatitis (NASH) is estimated
to affect approximately 25% of patients with NAFLD and approximately 1-2% of
patients will progress to cirrhosis, although the risk is higher (up to 10-15%)
in those with type 2 diabetes, obesity, or those with excess alcohol
consumption (where the condition is often referred to as BAFLD – both alcohol
and NAFLD).
Most patients with NAFLD will not die of liver related
complications – 8 of 10 patients with NAFLD will die of cardiovascular disease. However, NAFLD is an independent risk factor
for heart disease and strokes, and it increases the risk of developing diabetes. There is also evidence that it increases the
risk of other tumours like colon cancer.
Symptoms of NAFLD
NAFLD does not present with symptoms until the late stages,
when the complications of cirrhosis develop. Some patients may complain of
vague symptoms such as upper abdominal discomfort, itch, or fatigue. This is why liver disease is frequently
dubbed ‘the silent killer’. In the late
stages it may present with jaundice, encephalopathy (confusion), haematemesis (vomiting
blood- due to oesophageal varices), ascites, oedema, or liver cancer.
Diagnosis of NAFLD
Routine blood tests often miss the disease, as up to 80% of
patients with NAFLD will have a normal ALT (a liver enzyme) at any one time,
even with advanced disease. Gamma GT
(another liver enzyme) is often raised, but is quite non-specific, and low
platelets (one of the cellular components of the blood) is often a sign of
cirrhosis with portal hypertension. We
use non-invasive risk scores, such as the Fib4 score (calculated from AST, ALT,
platelet count and age) to assess the risk of someone have significant fibrosis. These scores are good at ruling out significant
disease but are not very specific.
Transient elastography or Fibroscan, a special liver scan, can be used
to assess liver stiffness, which reflects the degree of fibrosis in the liver. The gold standard for diagnosis and staging
of NAFLD, however, is liver biopsy.
Treatment of NAFLD
There is no licensed drug treatment for NAFLD, although many
drugs are in different stages of development.
Medications such as vitamin E and Pioglitazone have been shown in
studies to be beneficial in patients with non-alcoholic steatohepatitis (NASH),
but their effectiveness has not been evaluated in any large randomised trial
(gold standard for research) and they are not widely used. Certain medications for type 2 diabetes (such
as Metformin and GLP1 analogues) have been shown to be anti-fibrotic in
patients with diabetes, and ACE inhibitors (medications for high blood
pressure) are thought to be beneficial in patients with hypertension.
As yet, the only proven effective way to treat NAFLD is
through weight loss. We know that losing
10% of body weight can not only improve steatosis and steatohepatitis, but also
reverse fibrosis. Weight loss also helps
to reduce associated cardiovascular risk.
Weight loss can be achieved through dietary and lifestyle changes.
However, weight loss with dietary and lifestyle changes is usually modest and
most patients do not maintain the weight loss. Resistance exercise has been
shown to be of benefit even in the absence of weight loss. Some medications
might help with achieving bigger weight loss. However, bariatric surgery is the
most effective treatment for obesity and consequently can also be an effective
treatment for NAFLD. Better access to the
full spectrum of obesity treatments is required to help patients achieve and
maintain significant weight loss.
The following questions will be discussed in the chat.
1)
How to spot a patient with significant liver
disease? Should all patients with obesity (or who undergo bariatric surgery) be
screened/tested for NAFLD?
2)
How should patients with NAFLD be
treated/managed? What medications are useful/should be avoided in patients with
NAFLD?
3)
How, and how frequently, should a patient with
NAFLD be monitored?
4)
What is the role of different obesity treatments
in the management of patients with NAFLD?
5)
Among bariatric surgery options, is there an
option that is preferable in patients with NAFLD? Are there contraindications
for bariatric surgery in patients with NAFLD?
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