Distributional Cost-Effectiveness Analysis of Antenatal Lifestyle Interventions to Reduce the Incidence of Gestational Diabetes and Type-2 Diabetes

OBJECTIVES: To evaluate the population net health benefit and distributional health impact across socioeconomic subgroups when considering alternative target populations for implementing antenatal lifestyle interventions in Australia. METHODS: Differences in the distributions of health within population subgroups defined by Socioeconomic Index for Areas quintiles were compared for standard care (no routine antenatal lifestyle intervention) versus subsidized provision to (1) all pregnant women, (2) women with body mass index (BMI) ≥ 25, (3) women aged ≥ 30 years, or (4) women giving birth within the public health system. Distributional cost-effectiveness analysis of the alternative implementation strategies was conducted to model the impact on disease incidence (gestational and type-2 diabetes), direct healthcare costs, opportunity costs, mortality and quality-adjusted life-years for socioeconomic subgroups. Data were obtained from national statistics, registries and the literature. Value judgements regarding aversion to social inequality in health were captured using the Atkinson index. Extensive sensitivity analyses were conducted. RESULTS: At an opportunity-cost threshold of AU$31 157 (2024 prices), all implementation strategies improved overall population health and reduced health inequality compared with current standard care. Provision to women with a BMI ≥ 25 generated the highest population net health benefit, whereas provision only within the public health system generated the greatest reduction in health inequality. Sensitivity analyses did not materially change these findings. CONCLUSIONS: Among the targeted strategies evaluated, limiting implementation to women with BMI ≥ 25 is likely to result in the greatest incremental population net health gains and is the preferred strategy when trade-offs between efficiency and health equity are considered.