To be honest, I don't think this guideline is terribly helpful. I've done a brief summary, then more detailed notes. In summary:
There is no advice on who to test to diagnose NAFLD, nor what tests to use in diagnosis. Once diagnosed, there should be an assessment for 'advanced liver fibrosis'. NICE advises using the 'enhanced liver fibrosis test' to do this. People scoring highly will need specialist referral. Others will need retesting regularly.
Children will need screening every 3 years with USS if they have type 2 diabetes (T2DM) or metabolic syndrome. If diagnosed, they need specialist referral.
All patients with NAFLD
Advise them to stick to national alcohol intake limits, to exercise and to lose weight if overweight. There is no benefit from starting statins just for NAFLD. Pioglitazone (in adults only) and Vitamin E can be used in secondary care in those with advanced liver fibrosis.
More detailed notes
Identifying NAFLD in adults
NAFLD is more common in patients with T2DM or with metabolic syndrome.
NICE has not given specific advice on who to test for NAFLD. They have also not advised what specific tests to use because there is just not enough evidence for them to give specific advice. Therefore patients will be found when they have abnormal LFTs or an abnormal USS.
Of note, 70% of patients with NAFLD will have normal LFTs, so you can not use normal LFTs to rule out NAFLD.
Ruling out other liver disease
Before making a diagnosis of NAFLD, other forms of liver disease need to be ruled out. No advice on specific tests has been given. The guideline advises that we use our 'clinical discretion'. Tests that have been listed as possibly being helpful include: Hep B, Hep C, autoimmune liver disease, coeliac disease, haemochromatosis, Wilson's etc.
Alcoholic liver disease must be ruled out. In order to rule it out, patients should be drinking within the national alcohol guidelines (which may be a minority of patients!). They advise that this may be in line with WHO recommendations on 'hazardous drinking', which is where the drinking increases the risk of harmful consequences. Hazardous drinking involves patterns of use that are of public health significance, even if there is no current disorder in the individual.
Identifying NAFLD in children and young people under 18
Do a liver USS if:
- Have T2DM or metabolic disease AND
- Do not abuse alcohol
NAFLD found? Refer to a specialist.
NAFLD not found? Repeat USS every 3 yrs
How to further assess people with NAFLD
Test for advanced liver fibrosis.
Consider using the 'enhanced liver fibrosis (ELF) test' to do this. This test looks at three different serum markers for fibrosis. The results are then combined in an algorithm. It is highly specific and sensitive and is the most cost-effective test that NICE looked at.
- ELF score 10.51 or above - diagnose advanced liver fibrosis and refer to a specialist.
- ELF score below 10.51 - reassure that they are unlikely to have advanced liver fibrosis. Retest adults every 3 yrs and children every 2 yrs.
NB - the NAFLD score, which is widely used was evaluated and was considered to be a good test, just not as cost-effective as the enhanced liver fibrosis test.
Cirrhosis - monitor patients for cirrhosis as per the new NICE guideline (I will summarise this soon).
General advice to give patients
- Physical activity - there is some evidence that exercise reduces liver fat content.
- Alcohol - stay within national guidelines (alcohol + NAFLD has more than additive risks for cirrhosis).
- Diet - if overweight or obese.
Medical conditions associated with NAFLD
The following conditions are more likely in patients with NAFLD:
- T2DM (and patients with NAFLD and T2DM are at higher risk of AF, MI, ischaemic stroke and death from cardiovascular causes).
Drugs used in the management of NAFLD
Statins - do not start statins purely for NAFLD. There is one RCT showing that statins can improve LFTs, but no improvement in steatosis or fibrosis. It is fine to continue statins if patients are already on them. Only consider stopping if the liver enzymes double within 3m of starting statins.
Pioglitazone and vitamin E can be started for patients with NAFLD and advanced liver fibrosis. It is specialist use only. This applies even to non-diabetic patients. Both have been shown to improve histological findings and to improve NAFLD scores.
Vitamin E can be started by specialists for patients with NAFLD and advanced liver disease. No studies have been done on pioglitazone in children and young people, so it can not be recommended.