Estimates presented at the AMCP Nexus 2024 meeting indicate that metabolic dysfunction-associated steatohepatitis (MASH) and metabolic dysfunction-associated steatotic liver disease (MASLD) are significantly underdiagnosed in the United States. The research suggests that the true prevalence rates of these conditions are higher than what is currently reflected in claims diagnosis codes.
Forecasting MASH Prevalence
One study utilized two forecasting methods to estimate the diagnosis rates and prevalence of MASH over time. The epidemiological, illness-death model, drawing from Optum Clinformatics Data Mart and Veradigm electronic health records linked to Komodo claims (2015-2022), estimated diagnosed MASH prevalence in 2025 to be between 0.5% and 1.0%. A parametric statistical model, using National Health and Nutrition Examination Survey data from 1988-2020, projected a slightly higher prevalence of 1.0% to 1.7% for the same year. By 2040, the models project the prevalence to grow to 0.8% to 1.9% and 2.8% to 4.6%, respectively.
Quantifying Underdiagnosis
Another study employed a mathematical framework to quantify the underdiagnosis of MASH and MASLD using claims data from a 100% sample of Medicare fee-for-service beneficiaries. The researchers defined MASLD and MASH as having at least one inpatient claim or at least two outpatient claims with relevant diagnosis codes. The dataset included 15,105,608 individuals enrolled from January 1, 2017, to December 31, 2022.
The results indicated that after applying the prevalence to the 2022 cohort, the prevalence of MASLD rose from 1.49% to an estimated true prevalence of 5.30% in 2022, and MASH rose from 0.26% to an estimated true prevalence of 0.85%.
Implications for Treatment and Budget Impact
These findings have significant implications for healthcare decision-makers, particularly in light of recent FDA approvals of treatments for MASH. As the authors noted, "Decision-makers can use this epidemiologic information to better assess budget impact of new therapeutics for [MASH]." The underdiagnosis of MASH and MASLD suggests that a larger patient population may benefit from these new therapies than previously estimated.
