MetALD: alcohol and fatty liver

The three subgroups

In 2023 the international liver societies replaced the old names. More than 75 societies endorsed the change, and it is now what appears on reports and referrals, so it is worth understanding what the labels mean.

Steatotic liver disease is the umbrella term for any liver carrying excess fat. Underneath it sit three subgroups, and which one applies depends on two things: whether you have at least one cardiometabolic risk factor, and how much alcohol you drink.

Why MetALD was created

Because the old system forced a choice that does not match real people. The previous name, non-alcoholic fatty liver disease, defined the condition by what it was not, and required alcohol to be ruled out before the diagnosis could be made. In practice a large number of people have both a metabolic problem and a drinking pattern above the national guideline, and the two do not simply add up. They multiply.

MetALD is not rare. Pooled across 19 studies covering more than four and a half million adults with a fatty liver, around 10 per cent fall into the MetALD group, and it is far more common in men, who made up 86 per cent of cases. Compared with people who have no fatty liver, that group carried higher all-cause mortality, higher cardiovascular mortality and a substantially higher rate of the liver decompensating.

Why the alcohol question keeps getting asked

Nobody enjoys being asked how much they drink, particularly twice. There is a clinical reason for it, and it is not suspicion.

Alcohol intake is under-reported almost universally when liver disease is being assessed. Across the studies, 58 per cent of people under-report what they drink in that setting, and between 12 and 30 per cent of people drinking heavily are not classified as having alcohol-related liver disease because of it. That is not dishonesty so much as the ordinary human business of not counting, pouring generously at home, and rounding down.

The consequence is not a moral one, it is a prognostic one. A Swedish study followed more than 15,000 people carrying a diagnosis of MASLD. Twelve per cent already had an alcohol-related diagnosis recorded before the liver diagnosis, and another 5 per cent acquired one afterwards, so roughly one in six turned out to have had an alcohol component all along. Their rate of serious liver outcomes was 19.5 per cent against 7.8 per cent in the rest, around three times higher after adjustment. For those whose alcohol diagnosis came after the liver diagnosis, the rate was nearly six times higher.

Phosphatidylethanol, the blood test that measures it directly

Phosphatidylethanol, usually shortened to PEth, is a substance formed in red blood cells only when alcohol is present. It reflects drinking over roughly the previous one to four weeks, which makes it far more useful than a blood alcohol level, which only covers the last few hours, and more reliable than the older liver markers, which are affected by many other things.

How it reads in practice:

• Below 0.05 micromol per litre. Abstinence, or only occasional minor drinking
• 0.05 to 0.30. Regular drinking in the range that suggests MetALD rather than MASLD
• Above 0.30. Regular drinking at a level consistent with alcohol-related liver disease

A Stockholm study applied it to more than 46,000 people. Among 6,377 carrying a presumed MASLD label, 20 per cent had a PEth in the MetALD range and a further 13 per cent in the ALD range. Put plainly, a third of people labelled MASLD had an alcohol marker above the minimal-intake level. Higher PEth tracked with more liver events even in people without cirrhosis, and even after accounting for age, sex and fibrosis score.

The test is not a trap and it is not ordered routinely. It is useful when the picture does not add up: a liver that looks worse than the metabolic risk factors would explain, blood tests that do not settle, or a decision about treatment that hinges on which of the three diagnoses is correct. It is a decision made with you rather than about you.

Why it tends to be found late

Liver disease where alcohol plays a part is usually picked up much later than liver disease that is purely metabolic, and the reasons are structural rather than medical.

• There are no symptoms until late. The liver carries on without complaint through the stages where treatment works best
• Blood tests can look normal. The standard liver enzymes are an unreliable guide, and a normal set does not exclude significant scarring
• The alcohol question is often not asked, or not answered fully. Which means the risk is scored as lower than it is
• Stigma keeps people away. People who suspect alcohol is involved frequently avoid seeking help for exactly that reason

The consequence is visible in the numbers. Alcohol-related and metabolic-and-alcohol-related liver disease together account for around 20 million cases of compensated cirrhosis worldwide and more than 330,000 cirrhosis deaths a year, and most of those people are diagnosed only once the liver has begun to fail. Yet more than 90 per cent of people who go on to develop decompensated cirrhosis had been in contact with the health system years beforehand, often about something alcohol-related. The opportunity to find it earlier was there and was missed.

What actually helps

Two drivers means two levers, and both are worth pulling. The alcohol one tends to work faster.

On the alcohol side

• Count properly for two weeks. Not an estimate. Measure what goes in the glass once and you will usually find the real number is higher than the remembered one
• Reduce rather than agonise. Fat from alcohol clears from the liver within weeks of cutting down, and the benefit does not require stopping altogether unless there is advanced scarring
• Drink-free days work better than smaller glasses for most people, because they are easier to keep track of
• Ask for help if cutting down is hard. That is a normal part of liver care and there is effective support for it, including from your GP

On the metabolic side

Everything that applies to MASLD applies here too, and stopping drinking does not fix it. Weight, blood sugar, blood pressure and cholesterol all still need attention, and the weight targets, the dietary pattern and the exercise targets are set out in full on the fatty liver disease page.

What changes once the label changes

Being told the diagnosis is MetALD rather than MASLD is not a reprimand. It changes four practical things.

• The outlook. The risk of the liver decompensating is higher, so the assessment of scarring matters more and is repeated sooner
• The treatment. Reducing alcohol becomes part of the plan rather than a general health suggestion, and it is the change with the fastest effect on the liver
• The follow-up. Closer review, because this group was previously being watched as though the risk were lower than it is
• The conversation. It opens the question of whether support with cutting down would help, which is a normal part of liver care rather than a referral to something else

How the scarring itself is staged, from a FIB-4 blood score through to a liver stiffness scan, is the same for all three subgroups and is set out on the fatty liver disease page.

Where MetALD is assessed in Sydney

A/Prof Viraj Kariyawasam is a consultant gastroenterologist and hepatologist. Fatty liver disease, including the assessment of scarring and the question of where alcohol fits, is assessed at consultation in Norwest, Rouse Hill, Pennant Hills and Macquarie Park.

Where further assessment or endoscopy is needed, it is arranged at Norwest Private Hospital, Macquarie University Hospital and Pennant Hills Day Surgery. A referral from your GP is needed for a consultation.