From the AGA Journals

Nonalcoholic fatty liver disease will keep rising ‘in near term’

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National strategy for dealing with NAFLD needed

Kanwal and colleagues present an interesting study assessing the trends in the incidence and prevalence of NAFLD in the United States. Findings suggest that the annual incidence of NAFLD has generally been stable (2.2%-3.2%), while the prevalence of NAFLD has increased by 2.8-fold (6.3%-17.6%). These findings are consistent with the literature and provide additional evidence supporting the increasing burden of NAFLD. Although an important study, there are some limitations to the study design. First, the diagnosis of NAFLD was solely based on elevated liver enzymes, which can underestimate the true incidence and prevalence of NAFLD. In fact, in a recent meta-analysis, NAFLD prevalence based on liver enzymes was 13%, while NAFLD prevalence based on radiologic diagnosis was 25% (Hepatology. 2015 Dec 28. doi: 10.1002/hep.28431. [Epub ahead of print]). Second, the study subjects came from the VA system, which may not be representative of the U.S. population (Patrick AFB, FL: Defense Equal Opportunity Management Institute, 2010). This is important because sex-specific differences in the prevalence of NAFLD have been reported (Hepatology. 2015 Dec 28. doi: 10.1002/hep.28431. [Epub ahead of print]). Nevertheless, these limitations do not minimize the important contribution of this study. There appears to be an alarming increase in the burden of NAFLD within all the racial and age groups in the U.S. Further, this increase in the incidence and prevalence of NAFLD is especially significant among the younger age groups (less than 45 years). This finding is in contrast to others who have reported a higher prevalence in older subjects (Presented at AASLD 2015. San Francisco. Abstract #534). If confirmed, this younger cohort of patients with NAFLD can fuel the future burden of liver disease for the next few decades (JAMA. 2012;307:491-7). Given the current lack of an effective treatment for NAFLD, a national strategy to deal with this important and rising cause of chronic liver disease is urgently needed.

Dr. Zobair M. Younossi, MPH, FACG, AGAF, FAASLD, is chairman, department of medicine, Inova Fairfax Hospital; vice president for research, Inova Health System; professor of medicine, VCU-Inova Campus and Beatty Center for Integrated Research, Falls Church, Va. He has consulted for Gilead, AbbVie, Intercept, BMS, and GSK.




Nonalcoholic fatty liver disease (NAFLD) almost tripled among United States veterans in a recent 9-year period, investigators reported in the February issue of Clinical Gastroenterology and Hepatology.

The trend “was evident in all racial groups, across all age groups, and in both genders,” said Dr. Fasiha Kanwal of the Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, both in Houston, and her associates. The increasing prevalence of NAFLD “is likely generalizable to nonveterans,” and will probably persist because of a “fairly steady” 2%-3% overall annual incidence and a steeper rise among younger individuals, they added. “Nonalcoholic fatty liver disease will continue to remain a major public health problem in the United States, at least in the near and intermediate future.”

Dr. Fasiha Kanwal

Dr. Fasiha Kanwal

Although NAFLD is the leading cause of chronic liver failure in the United States, few studies have examined its incidence or prevalence over time, which are key to predicting future disease burden. Therefore, the investigators analyzed data for more than 9.78 million patients who visited the VA at least once between 2003 and 2011. They defined NAFLD as at least two elevated alanine aminotransferase (ALT) values (greater than 40 IU/mL) separated by at least 6 months, with no history of positive serology for hepatitis B surface antigen or hepatitis C virus RNA, and no alcohol-related ICD-9 codes or positive AUDIT-C scores within a year of elevated ALT levels (Clin Gastroenterol Hepatol. 2015 Aug 7. doi: 10.1016/j.cgh.2015.08.010).

During the study period, more than 1.3 million patients, or 13.6%, met the definition of NAFLD, said the researchers. Age-adjusted incidence rates dropped slightly from 3.16% in 2003 to 2.5% in 2011, ranging between 2.3% and 2.7% in most years. Prevalence, however, rose from 6.3% in 2003 (95% confidence interval, 6.26%-6.3%) to 17.6% in 2011 (95% CI, 17.58%-17.65%), a 2.8-fold increase. Moreover, about one in five patients with NAFLD who visited the VA in 2011 was at risk for advanced fibrosis.

Among individuals who were younger than 45 years, the incidence of NAFLD rose from 2.3 to 4.3 cases per 100 persons (annual percentage change, 7.4%; 95% CI, 5.7% to 9.2%), the researchers also found. “Although recent studies show that the rate of increase in both obesity and diabetes, which are both major risk factors for NAFLD, may be slowing down in the U.S., this may not be the case in the VA, where the prevalence of obesity and diabetes is in fact higher than in the U.S. population,” they said.

In general, the findings mirror a recent analysis of the National Health and Nutrition Examination Survey (Aliment Pharmacol Ther. 2015 Jan;41[1]:65-76), according to the investigators. “The VA is the largest integrated health care system in the United States,” they added. “We believe that the sheer size of the veteran cohort, combined with a complete dearth of information regarding the burden of NAFLD in the VA, renders our findings highly significant. Furthermore, the VA is in a unique position to test and implement systemic changes in medical care delivery to improve the health care of NAFLD patients.”

The study was partially supported by the Michael E. DeBakey Veterans Affairs Medical Center. The researchers had no disclosures.

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