Psoriatic Disease and MASLD: What Is the Connection?

This transcript has been edited for clarity. 
Hello. I’m Dr Danielle Brandman. I’m the medical director of liver transplantation at NewYork-Presbyterian | Weill Cornell Medicine in New York City. Today I’ll be discussing fatty liver, which we now call metabolic dysfunction–associated steatotic liver disease, or MASLD. I’ll focus on how this disease may affect people with psoriatic disease.
MASLD is really quite common; it affects about 30% of the entire world’s population. What is MASLD? MASLD is defined as having fat or steatosis in the liver, in combination with at least one cardiometabolic risk factor, such as overweight or obesity (particularly if the weight is concentrated in the midsection), diabetes or insulin resistance, elevated cholesterol, and/or elevated blood pressure.
This disease is often identified when you’re having routine blood work and elevated liver enzymes are identified, or when some sort of abdominal imaging study, such as an ultrasound, CT scan, or MRI, is being done to evaluate symptoms like abdominal pain. 
We know that MASLD is more common in certain diseases, such as diabetes. Up to 70% of people with diabetes may have MASLD. Of course, our focus is on psoriatic disease, and we know that patients with psoriatic disease, particularly psoriasis and even more so psoriatic arthritis, appear to be more affected by MASLD than patients who don’t have these diseases. MASLD has been observed in 50%-70% of people who have psoriatic disease. 
Some studies have also suggested that the severity of psoriatic disease may amplify the risk of developing MASLD. Why is it that patients with psoriatic disease have MASLD? You would think that this is a disease that affects the skin and the joints; how could the liver be involved? In psoriatic disease, inflammatory substances and processes contribute to skin and joint disease that may also affect multiple other organ systems, including the liver.
There’s also a hypothesis about something called the hepato-dermal axis — a connection between the liver and the skin. One thought is that the inflammatory substances are released by white blood cells in the skin, and ultimately, they circulate into the liver and cause damage in the liver. On the flip side, there’s a thought that maybe the inflammation starts in the liver and ultimately impacts inflammation in the skin and development of psoriasis.
The other potential link is that the systemic inflammation that is present in psoriatic disease may affect body composition, and this may decrease lean muscle mass and increase blood central or midsection fat, and also increase the risk of diabetes, because those conditions are some of the driving factors in MASLD.
The other thing to keep in mind is one of the medications that’s used to treat psoriatic disease, methotrexate. Methotrexate may contribute to liver damage, particularly if someone drinks significant quantities of alcohol. Also, people who have classic metabolic risk factors for MASLD may be more prone to developing liver injury from methotrexate.
It can get really tricky because some of the patterns of injury from methotrexate may match what we see in MASLD. People who have psoriatic disease and MASLD may have that common risk factor of obesity and diabetes. It can be really tough to tease out. Is it just a liver disease that was going to happen? Is it a result of the psoriatic disease, is it a result of methotrexate, or is it a combination of all these factors? 
We do think it’s safe to take methotrexate, even in the setting of MASLD. The only cases where we recommend stopping the medication or using it with more caution are those in which there are signs of liver dysfunction or there are signs of advanced liver scarring or cirrhosis.
If you are treated with methotrexate, your doctor is going to monitor your liver enzymes closely. If the liver enzymes are elevated, particularly before methotrexate starts, then you should be connected to a hepatologist for further evaluation. 
What happens if you do have MASLD? I think people sometimes hear about having liver disease and they automatically think that they’re going to develop liver failure, but that’s not necessarily true. The most important factor that predicts the likelihood of having a liver-related event is the severity of liver scarring. We assess liver fibrosis or liver scarring on a scale of 0 to 4, where 0 to 1 is early, 2 is significant, 3 is advanced, and 4 is cirrhosis. It is critical that people who do have more advanced disease be referred to a hepatologist for further evaluation and ongoing care.
Outside of a hepatologist practice, your doctor can help determine whether you’re at risk of having advanced fibrosis. One of those ways is by using some routine blood tests, such as platelet count and liver enzymes, to calculate a FIB-4 score. The FIB-4 value may help classify whether you’re at low, high, or intermediate risk of having significant liver disease. 
People who have intermediate risk may require additional testing. Those with high risk should see a hepatologist for further care. Several studies suggest that when we use some of these noninvasive tests, like the FIB-4 or the FibroScan, 10%-25% of patients with psoriatic disease may have MASLD with significant fibrosis and 5%-14% may have advanced fibrosis.
If you have psoriatic disease plus diabetes, this may amplify the risk for advanced fibrosis. Thankfully, this liver disease is treatable and manageable. The cornerstone of treatment is focusing on weight management, with a target of losing 7% of your starting weight. It’s even better if you can lose 10% because that can reverse liver fat, liver inflammation, and liver scarring.
There is only one medication available [resmetirom] to treat MASLD. It is reserved for people who have either stage 2 or 3 liver fibrosis, but there are many medications being studied to treat this very common liver disease. 
What I hope you have taken away from this video today is that MASLD is very common in the presence of psoriatic disease. If you have psoriatic disease, you should be screened for MASLD. If you have signs of advanced fibrosis or we’re not able to figure out whether you have advanced fibrosis, you should be referred to a liver specialist for further testing. Thank you.