The diagnosis and management of nonalcoholic fatty liver disease: A patient‐friendly summary of the 2018 AASLD guidelines

Abstract

Content available: Author Interview and Audio Recording Non-alcoholic fatty liver disease (NAFLD) is defined by the presence of fat in the liver without evidence of other causes of fat accumulation in the liver such as alcohol use, hepatitis C, or certain medications. It is commonly associated with obesity, diabetes, and elevated cholesterol. Currently, about 25% of the global population has a diagnosis of NAFLD. In about 6% of patients with NAFLD the fatty accumulation causes liver inflammation, and this condition is known as non-alcoholic steatohepatitis (NASH). Individuals with NAFLD are at increased risk of cardiovascular disease and patients with NASH are also at risk of developing long-term liver injuries, and permanent scarring of the liver known as cirrhosis. Patient Summary: Fatty liver is commonly seen on liver ultrasounds or other forms of radiographic studies. When this happens with an increase in liver blood tests (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]), patients should be evaluated for NAFLD. This evaluation should include an assessment for metabolic risk factors such as diabetes, hypertension, obesity, or elevated cholesterol. Routine screening for NAFLD is not recommended, and family members of patients with NAFLD do not need to be screened. Key Point: People with metabolic diseases such as type 2 diabetes, obesity, or metabolic syndrome are at high risk for NAFLD. However screening is not currently recommended. This could always change as new tests and treatments for NAFLD are developed. Patient summary: Several liver diseases can cause a fatty liver or elevated liver enzymes. NAFLD can only be diagnosed once other forms of chronic liver disease are ruled out. A common alternative cause of fatty liver disease is significant alcohol consumption (defined as more than 21 drinks a week for men, and more than 14 drinks a week for women), although fatty liver can occur with lower alcohol intake. Another cause is autoimmune hepatitis (AIH) which can lead to very high increases in liver blood tests. Other possible causes include hepatitis C, hepatitis B, certain medications such as amiodarone or methotrexate, or other genetic diseases. The diagnostic steps are summarized in Figure 1. Key Point: When evaluating patients with NAFLD, it is important to rule out other causes of fatty liver and evaluate for other common causes of chronic liver disease. Patient summary: Patients with many metabolic risk factors, diabetes, or elevated liver blood tests may need further non-invasive testing to see if there is liver damage or scarring. These tests include bloodwork, which can create predictive scores for advanced liver scarring (fibrosis) or cirrhosis such as the fibrosis-4 score, or imaging studies such as ultrasound, CT, or MRI. Additionally, “liver stiffness” can be evaluated by various imaging techniques such as ultrasound elastography to determine degree of scar without performing a biopsy. Key Point: NAFLD can cause fibrosis and cirrhosis and blood work and imaging studies are frequently done to assess the severity of the liver disease. Patient summary: Sometimes non-invasive testing cannot determine if an individual has advanced liver disease or not. In these cases, a piece of liver tissue is collected by a biopsy to see how much scarring is present in the liver. This evaluation can also rule out other causes of liver disease if there is any uncertainty of the diagnosis of NAFLD. Methods of evaluating for fibrosis are summarized in Figures 2 and 3. Key Point: Patients with NAFLD may need a biopsy to rule out other causes of chronic liver disease and to assess the liver for cirrhosis. Patient summary: Weight loss is the key to preventing harm from NAFLD. Eating 500–1000 Calories a day with moderate-intensity exercise is the best way to lose weight. Losing 7%–10% of body weight can improve liver fat and inflammation in patients with NASH and can even help reverse scarring. Medications are not recommended for treatment unless patients have severe scarring and proven NASH. Bariatric surgery can lead to weight loss in patients with NAFLD, but there is not enough data on safety or efficacy to recommend bariatric surgery as a treatment for NAFLD alone. Although it’s not mentioned in the guideline, it is important for patients with NAFLD to avoid alcohol, which could cause additional harm to the liver. Key Point: Weight loss is key to preventing long-term injury from NAFLD. Medications are only recommended if patients have severe inflammation or scarring in the liver. Patient summary: It is common for patients with NAFLD to have other metabolic diseases such as hypertension, diabetes, and coronary artery disease. Thus, NAFLD patients are at high risk for death due to cardiovascular disease, including strokes and heart attacks. It is important for patients to have these other disease states evaluated and managed to reduce risk. Statin medications to decrease cholesterol and improve cardiovascular disease risk are safe unless a patient has extremely advanced cirrhosis. Key Point: Evaluating and treating potential diabetes, hypertension, coronary artery disease, and high cholesterol is important in patients with NAFLD as they are at an increased risk of cardiovascular disease. Statins are safe to use unless the patient has very advanced cirrhosis. Patient summary: Some medications have been shown to reduce inflammation in patients with NASH. These include pioglitazone, which is a medication used to reduce blood sugar in patients with diabetes, and vitamin E, which is an anti-oxidant thought to reduce inflammation. Both of these medicines come with risks and thus should not be started unless it is proven the patient has NASH. This will likely involve getting a biopsy and patients should not start these medications without discussing them with their doctor. There are new medications being studied which will likely be recommended in the next update of the guidelines. This includes two other classes of medications that are used to lower blood sugar, and some examples include dulaglutide, semaglutide, liraglutide, dapagliflozin, empagliflozin, and canagliflozin.2 Deciding on which medication to take for diabetes depends on many patient specific factors and will require a decision with a doctor. Treatments are summarized in Table 1. Key Point: There are medical treatments for patients with NASH that can be used in conjunction with losing weight. These medicines do have risks which need to be discussed with a physician before starting. Patient summary: If patients develop cirrhosis from NASH they will need screening for liver cancer and varices. Varices are blood filled veins in the patient’s esophagus (throat) which can bleed in patients with cirrhosis and require evaluation and treatment. This is done by a camera evaluation of the esophagus and stomach called an upper endoscopy. This screening is done in all patients with cirrhosis and patients with NASH without cirrhosis do not need screening. Key Point: NASH can lead to cirrhosis which requires patients to have tests that screen for liver cancer and varices in the esophagus. Patient summary: NAFLD is common in children, however some genetic disorders can present the same and may need to be evaluated. Biopsy is considered when the diagnosis is uncertain and treatment is similar to that of adults with lifestyle modification being the first line of treatment. Vitamin E can be used but the long-term safety is unknown in children. Key Point: Children are treated the same as adults for NAFLD. Ruling out genetic disorders must be done as well as a standard evaluation and lifestyle modification is the first step in treatment.

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