This study assessed the cost-effectiveness for years of life lost, from the health system perspective, of the CLIP interventions in India, Pakistan, and Mozambique. Using the MRC Process Evaluation of Complex Interventions guidance (21) we observed that the incomplete implementation process overall resulted in no difference in outcomes between trial arms, and, therefore, a lack of cost-effectiveness. This was despite contextual adaptations of the generic protocol to create bespoke interventions for each country. However, once fidelity with the published protocol and implementation plan were achieved in terms of both dose and reach, maternal and perinatal mortality were significantly lower in women who received at least eight POM-guided contacts (four in Pakistan), and that in those scenarios the intervention had a high probability of cost-effectiveness in each country. The cost of the intervention was remarkably similar between the three countries on a per pregnancy basis (≈$12-16USD). In addition, in Pakistan, there were similar findings when including women’s families’ opportunity (out-of-pocket) costs for health system resource utilisation.
Several recent reviews have summarised the current evidence on CHW-led initiatives (22–24), and many previous studies have identified cost-effectiveness for a variety of CHW-led interventions in reproductive, maternal, neonatal, and child health (22,23), with further evidence supporting the use of integrated ‘packages’ of interventions (25). Despite this substantial body of information, many maternal health studies still do not include a health economic component (14), and those focussed on pre-eclampsia are based on diagnostic and clinical interventions, such as the use of magnesium sulphate (26,27). To our knowledge, this health economic analysis is the first to evaluate community-level interventions for pregnancy hypertension.
Our results are broadly consistent with prior findings, albeit requiring a frequency of contacts from CHWs that matches current WHO guidance. Indeed, the consistently observed decrease in maternal and perinatal mortality, and increase in cost-effectiveness, with at least eight POM-guided contacts provides external validation of the recent WHO recommendations for at least eight antenatal care contacts (28). The contextual moderators that influenced the fidelity of implementation probably included the numbers of deployed CHWs, competing demands on CHW time (e.g., ‘immunisation months’), the variable resilience of the emergency transport system once women at risk were identified, and the timeliness and quality of the clinical responses as women ascended the referral system.
Although the overall per-pregnancy costs were similar between countries, there was discrepancy in the cost of delivering at least eight POM-guided contacts, which was largely driven by differences in CHW training and incentive costs per-pregnancy. When considering at-scale implementation of interventions such as CLIP that require a high number of contacts to be effective, these cost differences would be important to consider, as CHW salaries and relative affordability differ between less-developed countries (29,30). That said, the relatively low cost in each country supports CHWs carrying out home-based visits during pregnancy in less-developed countries where interventions are urgently needed to reduce the burden of maternal and perinatal mortality.
Our study has several strengths. First, we prospectively collected both cost and outcome data within our clinical trial (11). Second, we implemented our intervention across three diverse settings in Africa and South Asia, and with a large sample size of >60,000 pregnant women overall. Therefore, we believe that our findings are generalisable to other less-developed country settings. Further, the details of our budget allow for clear understanding of the cost of scaling any one or all components of the intervention. In the case of Pakistan, we were further able to corroborate our main findings by including data on out-of-pocket costs to women and their families, and, therefore, providing a broader societal perspective on the cost-effectiveness.
The main challenge associated with our economic analyses is that we were unable to use disability-adjusted-life-years (DALY) that include maternal and perinatal morbidity as an outcome measure. This is due to a lack of reliable DALYs for the collected morbidities in each of India, Pakistan, and Mozambique. Given that we consistently observed similar results in maternal morbidity (no effect overall, decrease with at least eight POM contacts) to mortality (8) it is probable that the cost-effectiveness results seen here would be similar if this could be included.
On the other hand, survived neonatal morbidity was in some cases increased in the ³8 POM contact group, suggesting a trade-off between reduced mortality and increased survivable morbidity in neonates, which would require further exploration to determine severity as well as the values of women, health care providers, and their communities. Therefore, the inclusion of these data may have reduced the estimates of cost-efficacy seen here.
Furthermore, given the scale of the trial and complexities of the health systems, reliable data on the out-of-pocket costs to women and health system costs associated with being referred were unavailable in India and Mozambique; this limits our conclusions to that of a health system perspective, rather than the preferred ‘societal’ approach in these two countries (31). In Pakistan, family opportunity cost data were available, and results were broadly similar to the programmatic perspective. In addition, we did not adjust costs for differences in routine antenatal care-seeking between arms as these measures and the associated cost were not available. Despite this, these measures were broadly similar between trial arms, and, therefore, we do not anticipate that this influenced the results (7,9,10). Finally, the decision-tree model used here could not adjust for differences between women who received a low and high number of POM visits that would have an impact on mortality, which may introduce a bias due to possible confounding. That being said, adjustment for such differences that were measured did not affect the association between increased visits and reduced outcomes (7–10).
Depending on a decision maker’s willingness to pay, having CHWs deliver home-based interventions at WHO-recommended frequency thresholds, is probably a cost-effective method for reducing maternal and perinatal mortality. The similarity in the cost of CHW visits and per-pregnancy trial costs overall between countries points to generalisability to other less-developed countries.
As further emphasis is placed on increasing the number of antenatal contacts in less-developed countries, future studies should continue to assess the cost-effectiveness of delivering these contacts, and possible integrated interventions by CHWs. Our data suggest that CHW-based interventions can be effective and cost-effective if a sufficient number of workers are available to deliver them at the required frequency. Future studies should estimate health system and out-of-pocket expenses in settings where families bare the cost of facility-based care. In addition, there is a need for continued development of ‘years-of-life-disabled’ metrics for pregnancy-specific morbidities so that trials can better estimate the economic impact of their interventions.