The Curbsiders' 'Hot Takes'

NAFLD: It's More Than Just the Fat

Matthew F. Watto, MD; Paul N. Williams, MD


July 31, 2020

This transcript has been edited for clarity.

Matthew F. Watto, MD: We are back. Today we are talking about nonalcoholic fatty liver disease (NAFLD). Or is it metabolic-associated fatty liver disease (MAFLD)?

Paul N. Williams, MD: As the great Shakespeare once said, "NAFLD or MAFLD, that is the question." Tonight we had the good fortune of talking with the great Dr Scott Matherly, a preeminent hepatologist, about NAFLD/MAFLD. We want to share a couple of pearls that we took away from this episode. Matt, why don't you go first?

Watto: This pearl is about imaging. We often see an incidental finding on the CT or MRI report that says "steatosis." When Dr Matherly talks to patients about it, he says, "In order for us to see steatosis on imaging, at least 30% of your hepatocytes must be filled with fat." I had never heard that before, and I thought that was a neat fact to tuck away.

Matherly gives his patients a long talk about the liver and its physiology. He says that NAFLD is a big club which everyone will belong to because it's so prevalent. But what we worry about is a small group of people who have fibrosis and inflammation. About 20%-40% of those people can develop cirrhosis, and that's when many of the complications start to happen.

Williams: Along those lines, something I found striking was the laboratory analysis of NAFLD. It's not the fat but the inflammation that results from it. One way to measure inflammation is checking transaminase levels, but the reference values provided by your lab may not reflect the true extent of inflammation. So even a number slightly over 30 U/L might represent underlying inflammation, although they fall within your lab's reference range. So 30 U/L might actually be a pathologic value that should prompt a little more investigation.

Watto: That's a good point. Before we talked with Matherly, that was totally off my radar. I would say, "Your ALT is 38. You're good to go." The way he sees it is that, for a woman, that's almost twice the upper limit of normal.

Williams: One fact that spoke to my primary care heart was that not only are statins safe, but they are safe in patients with NAFLD or NASH and may even be beneficial in the presence of inflammation. Cardiovascular events are probably one of most common causes of death in this disease, so while statins might not reverse the underlying pathology, they may be protective against cardiovascular events such as heart attacks. You can be fairly liberal with statins. Even mild elevations of the transaminases should not alarm you. Just stay the course and watch the numbers and make sure they don't progress. But feel free to use statins in these patients; don't be afraid of them.

Watto: He put numbers on that. Even up to the 150-200 range, he will push through, saying it will be okay. Unless the patient has end-stage decompensated cirrhosis, he doesn't change anything.

One of the final points that I wanted to make is about treatment. We talked about treatment, mostly diet, exercise, and weight loss. He specifically mentioned 10% weight loss, so a person weighing 200 pounds would lose 20 pounds. That's 10% of their body weight, and that should help reverse some of the NASH and hopefully prevent some of the bad outcomes.

We talked a lot about agents like pioglitazone, vitamin E, and some of the newer diabetes drugs, some of which seemed to work, but not super well there, and there are definitely some downsides. This is such a complicated pathophysiology that you really need good old-fashioned diet and exercise. Diet and exercise would work by so many different mechanisms that we don't fully understand. That's probably why diet and exercise are currently the best treatment we have.

Williams: It should be an easy sell because it will make everything else better — knee pain, back pain, blood pressure — so in the greater context of the patient's health, it's just one more reason to focus on diet, weight loss, and exercise.

Watto: Thanks, everyone, for watching.

Click to hear the full episode on NAFLD, or find the Curbsiders podcasts on iTunes.

The Curbsiders is a national network of students, residents, and clinician educators from across the country, representing 15 different institutions. They "curbside" experts to deconstruct various topics in the world of medicine to provide listeners with clinical pearls, practice-changing knowledge, and bad puns. Learn more about their contributors and follow them on Twitter.

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