A Structured Literature Review of the Epidemiology and Disease Burden of Non-Alcoholic Steatohepatitis (NASH)

Abstract

Introduction: Non-Alcoholic Steatohepatitis (NASH) is a chronic, progressive disease characterized by fatty liver and liver cell injury, advancing to fibrosis, cirrhosis and hepatocellular carcinoma (HCC). Diagnosis involves liver biopsy; however, as a result of its high cost and invasiveness, NASH remains underdiagnosed, and accurate burden of disease (BoD) data are lacking. Our aim was to understand the epidemiological and BoD landscape in NASH and identify knowledge gaps.

Methods: The Ovid search engine was used to conduct a structured review, following quality systematic principles. It included publications that reported on epidemiology, quality of life (QoL) and BoD outcomes in NASH adults. Searches were limited to English language studies published between January 2007 and September 2017. Additional grey literature searches were conducted. A total of 53 references were selected; 38 were peer-reviewed and 15 were grey literature sources.

Results: NASH is estimated to affect 3-5% of the global population, most suffering from several comorbidities. Advancing fibrosis drives clinical outcomes, with approximately 20% of patients developing cirrhosis and/or HCC, the latter being a leading cause of death in NASH. A recent model predicted the 15-year survival of advanced fibrosis patients at F3 and F4 as 51.0% and 28.4%, respectively. The limited data consistently show that NASH patients experience significantly poorer QoL and higher costs compared to non-NASH patients.

Conclusion: This first broad-ranging examination of NASH literature revealed a paucity of evidence, with poor-quality, small studies found. The overwhelming impact of NASH and its patient and healthcare burden is evident. Further evidence is needed to improve our understanding of NASH, especially as fibrosis stages advance.

Funding: Gilead Science Inc.

Keywords: Burden of disease; Epidemiology; NASH; Non-alcoholic steatohepatitis.

Fig. 1

PRISMA diagram of included and excluded publications

Fig. 2

Publications captured in the literature review by study type. PRO patient-reported outcomes, RCT randomized controlled trial, SLR systematic literature review

Fig. 3

Overall NASH prevalence in the general population. NASH non-alcoholic steatohepatitis, UK United Kingdom, USA United States. ^aValues rounded to 1 decimal point

Fig. 4

NASH disease progression. F0/4 fibrosis stage 0/4, HCC hepatocellular carcinoma, NASH non-alcoholic steatohepatitis. Data adapted from Traussnigg et al. [45]