The PPA model of care was cost-effective in reducing cesarean sections in a private hospital located in the southeast of Brazil, the most developed region of the country. The Brazilian government does not recommend a threshold value for decisions on the incorporation of new technologies in the National Health System 28. Therefore, we used a threshold value recommended for the evaluation of interventions in middle-income countries 26. If we used the threshold of less than 1GDP per effectiveness recommended by the World Health Organization 29, the PPA model of care would be very cost-effective.
The two parameters with the greatest influence on the cost-effectiveness results - the average cost of hospitalizations for vaginal births and cesarean sections without complications - are not related to the model of care. However, they are important parameters in the context of childbirth care in Brazilian private hospitals, since there are different arrangements for paying for hospitalizations in these hospitals. The inpatient package model, used in the hospital included in this case study, is the most common. In this model, the health plan operator defines the cost of hospitalizations for uncomplicated vaginal births and cesarean sections with a wide variation of this value according to the type of health plan. In this study, the average cost of uncomplicated vaginal birth and cesarean sections was higher in women assisted in the PPA model of care. Scenario analysis adopting the same average cost of hospitalization for uncomplicated vaginal and cesarean sections in the two models of care, using a wide range of values, resulted in lower ICER values for avoided cesarean section, making the PPA model of care even more cost- effective.
The other parameters found to influence the ICER were the proportion of cesarean sections and the proportion of neonatal complications, especially those related to vaginal deliveries. The greater the reduction in the rate of cesarean section in the PPA model of care, and the lower the occurrence of neonatal complications, the more cost-effective this model of care is. In a scenario of lower reduction in the cesarean section rate, reaching a rate of 50% in the PPA model of care group, the ICER would rise to US$ 1,848.59 per avoided cesarean section. Regarding neonatal complications, the significantly higher proportion of meconium aspiration syndrome in the PPA group indicate that there are possibilities for improving the quality of childbirth care in this model of care.
The 2/3 reduction in the cesarean section rate in the PPA model of care, in both crude and weighted analysis, is consistent with two previous studies that evaluated the effects of interventions to reduce cesarean sections in Brazilian private hospitals, which also found significantly lower rates of cesarean Sect. 16, 17. All these interventions have as common characteristics the implementation of models of care that promote physiological childbirth through adjustments in the hospital environment, implementation of clinical guidelines based on best clinical practices, promotion of the collaborative model of care between doctor and nurse-midwives during labor and childbirth care, and educational work with women.
The group of women assisted by the standard of care model had a much higher proportion of women in the Robson´s groups 2b and 4b, similar to a previous national study carried out in 2011–2012, where group 2b was the most frequent group in Brazilian private hospitals 30. In the PPA model of care, groups 1 and 2a were the most frequent. Almost 90% of women in the PPA group presented labor, while in the standard of care model this value was lower than 25%. Finally, in the PPA model of care the proportion of induced labor was seven times higher than that observed in the standard of care model, where the induction rate was less than 5%. All these results suggest that the differences found between the two models of care are due to the actions implemented by the PPA. A more global change in the private sector is less likely, as women assisted by external teams showed the same pattern seen in private hospitals in 2011–2012 10, 30. A 21% increase in the proportion of vaginal deliveries in the period 2014–2016 was also observed when comparing data from 5 hospitals participating in the PPA and 8 hospitals not participating in the city of São Paulo/Brazil 12.
Serious negative outcomes, such as maternal, fetal and neonatal deaths, severe maternal morbidity and maternal and neonatal near miss, presented low frequency and with non-significant differences between the two models of care. However, women in the standard of care model presented almost twice the proportion of early term births, most of them associated with antepartum cesarean sections. It is estimated that, in Brazil, about 35% of live births are early term 31, corresponding to more than 300 thousand early term births per year, with a higher prevalence in places with cesarean rates above 80% 32. In a previous nationwide Brazilian study, early term births, especially non-spontaneous births, were associated with several negative outcomes, such as oxygen use, neonatal ICU admission and neonatal death 31.
This study has some limitations. As we used data from only one hospital, we cannot extrapolate the observed results to the set of hospitals participating in the PPA, as the local contextual characteristics may have affected the implementation of the recommended actions and the observed effects 33. In addition, the study is probably underpowered to detect differences in less frequent results due to the small sample size.
Costs related to the implementation of the PPA were not included, as they were not available. Hospital managers, health plan operators and the project coordination should consider these expenses when deciding to implement the PPA in new maternity services.
Finally, we used a short time horizon. There is evidence of negative medium and long-term effects associated with cesarean section, both for women and newborns 3, 4. There is also evidence of more neonatal complications after hospital discharge in early term births, more frequently observed in the standard of care model.