The prevalence of non-alcoholic fatty liver disease (NAFLD) has reached epidemic levels. The most common liver disease, with a worldwide prevalence of 25%, NAFLD and its subtype, nonalcoholic steatohepatitis (NASH), affect 30% and 5% of the U.S. population, respectively. Given the ongoing obesity epidemic beginning in childhood, the rise in diabetes and other factors, the prevalence of NAFLD, along with the proportion of those with advanced liver disease, is expected to continue to rise.
Despite the urgent need to identify patients at high risk for progression to liver fibrosis, there are no firm guidelines for NAFLD screening in high risk individuals due to inadequate data on cost-effective treatment options.
For this reason, NASHNET developed a cost-effectiveness analysis to compare the value of screening in Type 2 diabetes (T2D) patients for NAFLD versus not screening. The findings were presented (abstract #1633) at the Association for the Study of Liver Disease’s (AASLD) Liver Meeting Digital Experience™ (TLMdX), Nov. 13-16, 2020.
Markov Model Refines Screening Methods
A Markov model was developed, which is used to model randomly changing systems, to analyze eight screening approaches. Three began with patients receiving an ultrasound (US) and aspartate aminotransferase (AST), three with US and alanine aminotransferase (ALT) and one with US only.
If any of these approaches detected NAFLD, screening proceeded to the next stage:
- Screening approaches 1 and 4→ liver biopsy
- Screening approaches 2 and 5→ vibration-controlled transient elastography (VCTE), and if this suggested ≥F2→ liver biopsy
- Screening approaches 3, 6 and 7→ VCTE
Finally, the simulation was performed starting with controlled attenuation parameter (CAP) of VCTE to detect steatosis along with stiffness suggesting ≥F2.
Post-detection, patients were hypothetically treated with weight reduction through intensive lifestyle intervention (ILI). Studies have shown that 10% of patients who received ILI are expected to lose over 10% of their body weight in 12 months.
Costs (USD) and quality-adjusted life years (QALYs) were discounted at 3%; the time horizon was lifetime. The threshold incremental cost-effectiveness ratio ≤$50,000 per QALY used was favored by the incremental cost-effectiveness ratio (ICER). All causes of mortality, including cardiovascular and liver-related, were considered.
Demonstrated Cost-Effectiveness of Screening
This model found that screening ≥55-year-old patients with T2D/NAFLD via all strategies other than liver biopsy were cost effective versus no screening–whether started with US+ALT, US+AST or US alone followed by VCTE—to detect significant fibrosis (≥F2). The same was true if the model started with CAP on VCTE accompanied by fibrosis determination (≥F2).
Conclusively, screening approaches that included liver biopsy were not cost-effective because of its associated disutility. The model also included an iteration starting at age of ≥40-year-old patients with T2D/NAFLD and found that screening strategies were also cost effective.
The economic analysis determined that non-invasive screening of patients with T2D/NAFLD in the United States is cost effective and should be adopted to identify those at greatest risk of adverse outcomes or who might benefit from treatment intervention.
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