To the Editor:

Lazris and colleagues concisely review the epidemiology and prognosis for non-alcoholic fatty liver disease (NAFLD) in adults.¹ However, their conclusions that “. . . it is unlikely that diagnosing NAFLD benefits patients” and “. . . the best approach to patients with metabolic syndrome is not labeling them with more diseases” are misleading.

The American Association for the Study of Liver Diseases does not recommend screening for NAFLD.² However, a patient with an incidental finding of elevated liver transaminases or hepatic steatosis on imaging warrants an appropriate workup.^2,3 The American Association for the Study of Liver Diseases guidelines and an American Family Physician article on NAFLD highlight the importance of risk stratification using decision aids or imaging, with a need for more frequent follow-up for patients at high risk.^2,3 Ultrasonography is the primary imaging modality in the workup of patients with elevated liver enzymes. The false-positive rate of 15% cited by Lazris and colleagues is misleading because that rate applies if ultrasonography is used as a screening test for all patients with type 2 diabetes mellitus.⁴ The actual false-positive rate of ultrasonography when used in the workup of patients with elevated liver enzymes is likely much lower. A meta-analysis found a sensitivity and specificity as high as 89% and 90%, respectively, compared with histology, when at least 20% to 30% of hepatocytes are affected.⁵ At 5% hepatocytes affected (which defines NAFLD), the sensitivity and specificity decrease to 65% and 81%, respectively; therefore, it is more likely NAFLD goes undiagnosed early in the disease process.⁵

Although most patients with NAFLD do not progress to cirrhosis or hepatic-related death, NAFLD represents a significant disease that may progress throughout a patient's lifetime if not managed appropriately.⁶ Most patients with NAFLD die from vascular causes, but NAFLD puts patients at increased risk of cardiovascular death.⁶ As the U.S. population continues to develop metabolic syndrome at an earlier age, hepatic-related deaths will likely become more prominent over time.⁶ Concurrent use of alcohol or hepatotoxic medication is likely to worsen hepatic-related outcomes for patients with undiagnosed NAFLD.⁶ Patients should be counseled on their diagnosis, and risk stratification should be performed periodically using a validated decision tool.^2,3 The diagnosis of NAFLD represents an opportunity to educate patients about the widespread effects of obesity on their health and is not merely a label.

The opinions and assertions contained herein are those of the authors and are not to be construed as official or reflecting the views of the U.S. Air Force Medical Corps, the U.S. Air Force at large, or the U.S. Department of Defense.

In Reply:

We generally agree with Dr. Wiley. Most of what we discussed in the article involves screening performed in people without elevated liver function test (LFT) results, who we think should not receive abdominal ultrasonography in the absence of other symptoms. We agree that people with elevated LFT results warrant radiologic and laboratory investigation to assess for possible reversible causes of hepatic dysfunction and to help determine prognosis. However, once the diagnosis of NAFLD is determined by ultrasonography, a discussion should occur between the physician and patient about the meaning of the diagnosis and its connection to metabolic syndrome, rather than labeling the patient with liver disease. Physicians should address the metabolic and dietary causes of NAFLD instead of repeating ultrasonography for surveillance purposes or routinely referring these patients to gastroenterologists. Certainly, follow-up LFT measurements and other laboratory tests would be warranted. NAFLD is less a liver disease than a manifestation of metabolic syndrome that should be addressed accordingly.