NAFLD screening a cost-effective approach among T2DM patients in SG

Nonalcoholic fatty liver disease (NAFLD) screening strategies, particularly vibration-controlled transient elastography (VCTE) and fibrosis-4 (FIB-4), are a cost-effective approach to reduce disease burden among type 2 diabetes mellitus (T2DM) patients in Singapore, according to a study.

“However, given the lack of access to VCTE at primacy care and potential budget constraints, FIB-4 can also be considered for NAFLD screening among T2DM patients in Singapore,” the researchers said.

The research team constructed a Markov model comparing four screening strategies with no screening to identify NAFLD with advanced fibrosis among T2DM patients: fibrosis-4 (FIB-4), vibration-controlled transient elastography (VCTE), FIB-4 and VCTE (simultaneous), and FIB-4 and VCTE (sequential). Parameter uncertainties in the results were assessed through sensitivity and price threshold analyses.

The most cost-effective NAFLD screening strategy was VCTE (USD 24,727/quality-adjusted life year [QALY]), followed by FIB-4 (USD 36,800/QALY), when compared with no screening. On probabilistic sensitivity analysis, VCTE showed a higher degree of certainty as a cost-effective approach relative to FIB-4 (90.7 percent vs 73.2 percent). [Ann Acad Med Singap 2022;51:686-694]

The superiority of VCTE over FIB-4 was due to the former’s better accuracy in identifying NAFLD with advanced fibrosis, which then results in more high-risk patients receiving early therapeutic intervention. [Clin Gastroenterol Hepatol 2019;17:2570-2580.e37]

The interpretation of VCTE, however, is currently not available at the community level, so the adoption of this strategy as the primary modality for population-based NAFLD screening should consider the availability of VCTE machines and trained technicians, according to the researchers.

Screening benefit duration

Based on incremental cost-effectiveness ratio tornado analysis, duration of expected screening benefit turned out to be the most influential variable. Specifically, the minimum duration of screening benefit for NAFLD screening to be cost-effective was at least 2.6 years. The annual cost of NAFLD treatment for NAFLD screening to be cost-effective must be less than USD 751.

“While it is logical to expect screening benefits to gradually taper off with time, this was not considered in prior cost-effectiveness studies,” the researchers said. [Medicine (Baltimore) 2017;96:e6585; Gastroenterology 2020;159:1985-1987.e4]

“We found that the benefits of screening should last at least 2.6 and 3.8 years for VCTE and FIB-4, respectively, for screening to remain cost-effective,” they added.

Additionally, it was beneficial to identify the target population of interest, wherein the screening benefit would be limited to patients with an expected life expectancy of <4 years from the point of NAFLD screening, according to the researchers.

“Our findings complement our current understanding of NAFLD screening by estimating the minimal duration of screening benefit and incorporating cardiovascular outcomes into the existing NAFLD model,” the researchers said. “With an expanding treatment armamentarium for NAFLD, our findings are timely in providing a cost-effective threshold for NAFLD treatment in the setting of population-based NAFLD screening.”

Of note, the SingHealth Diabetes Registry showed a high T2DM prevalence, which was consistent with other Asian studies. [Gut 2016;65:1359-1368]

“While our model described a once-off screening strategy, repeated screening may be considered in 3–5 years’ time, given that 50 percent of T2DM patients developed NAFLD in 3 years, even though few experienced fibrosis progressions within 3 years,” the researchers said. [Hepatology 2020;72:1230-1241]