Cost-effectiveness of low-dose aspirin for the prevention of preterm birth: a prospective study of the Global Network for Women's and Children's Health Research

Abstract

Background: Premature birth is associated with an increased risk of mortality and morbidity, and strategies to prevent preterm birth are few in number and resource intensive. In 2020, the ASPIRIN trial showed the efficacy of low-dose aspirin (LDA) in nulliparous, singleton pregnancies for the prevention of preterm birth. We sought to investigate the cost-effectiveness of this therapy in low-income and middle-income countries.

Methods: In this post-hoc, prospective, cost-effectiveness study, we constructed a probabilistic decision tree model to compare the benefits and costs of LDA treatment compared with standard care using primary data and published results from the ASPIRIN trial. In this analysis from a health-care sector perspective, we considered the costs and effects of LDA treatment, pregnancy outcomes, and neonatal health-care use. We did sensitivity analyses to understand the effect of the price of the LDA regimen, and the effectiveness of LDA in reducing both preterm birth and perinatal death.

Findings: In model simulations, LDA was associated with 141 averted preterm births, 74 averted perinatal deaths, and 31 averted hospitalisations per 10 000 pregnancies. The reduction in hospitalisation resulted in a cost of US$248 per averted preterm birth, $471 per averted perinatal death, and $15·95 per disability-adjusted life year.

Interpretation: LDA treatment in nulliparous, singleton pregnancies is a low-cost, effective treatment to reduce preterm birth and perinatal death. The low cost per disability-adjusted life year averted strengthens the evidence in support of prioritising the implementation of LDA in publicly funded health care in low-income and middle-income countries.

Funding: Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Figure 1:. Model design

We used this model to compare costs and benefits between standard care and LDA treatment. The first branching of the model separates pregnancy outcomes into mutually exclusive branches of term birth, preterm birth, and perinatal death. Term or preterm infants who died within 7 days of birth were not included in the term or preterm branches. When we ran this model for our LDA-treated sample, we reduced preterm birth and perinatal death per the relative risks reported in the ASPIRIN trial. Subsequent branches account for infant health-care use with hospitalisations and associated therapies, assuming receipt of a given therapy included receipt of all lower-intensity therapies. All branches are mutually exclusive, resulting in 15 different scenarios. CPAP=continuous positive airway pressure. LDA=low-dose aspirin.

Figure 2:. Cost per DALY averted in US$

The cost per DALY averted for the base case reflects health-care use cost data in Pakistan, which represented the median cost of the ASPIRIN trial sites. Results are sorted by their effect on the cost per DALY averted with LDA treatment. The low and high LDA cost were based on the low ($0·0042 per day) and the high ($0·0393 per day) price per tablet in the 2015 International Medical Products Price Guide (inflated to 2020 US$ using the gross domestic product deflator for Pakistan). Low and high LDA effectiveness estimates were based on the upper and lower 95% CI values reported in the ASPIRIN trial. For hospitalisation costs, the highest cost was in Pakistan ($94·00), but we increased the high cost to $200·00 to explore the effect of a higher than expected cost. Finally, we varied life expectancy across the range represented by the ASPIRIN trial sites (DR Congo had the shortest life expectancy [62·35 years] and Guatemala had the longest [72·02 years]). DALY=disability-adjusted life year. LDA=low-dose aspirin.