Burden of Illness and Economic Model for Patients With Nonalcoholic Steatohepatitis in the United States.

Nonalcoholic steatohepatitis (NASH) is the progressive form of nonalcoholic fatty liver disease. Our aim was to estimate the total economic burden of NASH and advanced NASH in the United States. We constructed lifetime Markov models for all stages of NASH and a separate model to specifically identify the increased burden of advanced NASH (fibrosis stage >3). The models comprised patients aged 18+, who moved through seven different health states. We used a lifetime horizon with 1-year cycles for each transition. Cohort size was estimated using US population data, and prevalence and incidence rates were obtained from the literature. Transition probabilities between states were derived from meta-analyses. Costs included inpatient, outpatient, professional services, emergency department, and drug costs, which were obtained from the Center for Medicare and Medicaid Services Fee Schedule 2017 and published data. All future costs were discounted at an annual rate of 3%. Our models estimated that there are 6.65 million adults (18+ years old) with NASH in the United States and that there were 232,000 incident cases in 2017. Lifetime costs of all NASH patients in the United States in 2017 will be $222.6 billion, and the cost of the advanced NASH population will be $95.4 billion. Conclusion: NASH, especially advanced NASH, is associated with high lifetime economic burden; in the absence of treatment, the total direct costs of illness for these patients will continue to grow, and these costs would be even greater if the societal costs are included.