Neonatal mortality inequalities in Peru, 2007-2021: an ecological joinpoint trends analysis

Background. Neonatal disorders remain the leading cause of loss of healthy life years worldwide, surpassed only by COVID-19 in 2021, even though at least 80% of the neonatal mortality burden is preventable. Neonatal mortality rate (NMR) –a prominent indicator in the 2030 Agenda for Sustainable Development– varies markedly between and within countries, indirectly reflecting the adverse impact of comparatively less favorable sanitary and social conditions on neonatal survival. Objective. To analyze the magnitude and trends of ecosocial inequalities in NMR in Peru, vis-à-vis national NMR and selected social determinants trends, their temporal correlation, inflection points, and changes in the epidemiological profile of neonatal deaths. Methods. Using an ecological design based on national and subnational administrative data covering the 25 Peruvian regions, 2007–2021 temporal trends in NMR and its inequalities across the intranational social gradient defined by monetary poverty, unmet basic needs, and food insecurity were analyzed. Absolute inequality in NMR was measured using the slope index of inequality (SII), while relative inequality in NMR was measured using the concentration index (CIx). Inflection points in trends were identified using joinpoint regression, and temporal monotonicity between them and a set of contextual variables was explored through Spearman's rank correlation. Temporal changes in the epidemiological profile of neonatal deaths were assessed using the Chi-square test of independence. Results. The NMR in Peru followed a downward trend, from 10.3 in 2007 to 8.8 per 1,000 lb in 2021, with a significant reduction from 2010 to 2014 (AAPC: -3.76%, 95%CI: -4.61; -2.27). With the exception of Huancavelica, Pasco and Puno, all Peruvian regions showed NMR descending trends. Cross-regional NMR inequalities showed a pro-rich pattern, mostly stationary, indicating an enduring survival disadvantage (SII: 5.0; [95%CI: 2.1; 7.9] excess neonatal deaths per 1,000 live births) of the regions with higher unmet basic needs at the end of the study period. NMR national trend showed high positive correlation with unmet basic needs (ρ = 0.82) and monetary poverty (ρ = 0.65) trends and high negative correlation with current health expenditure per capita (ρ=-0.79) and as a proportion of gross domestic product (ρ=-0.66) trends. Only the cross-region NMR inequalities as defined by food insecurity incidence showed high correlation with those contextual variables over time. There was a sizable reduction in NMR inequality in the COVID-19 years (SII: -7.5 to -4.5 from 2019 to 2021), due to a NMR reduction among the poorer regions (12.6 to 10.2 per 1,000 live births) and a NMR increase among the richer (from 5.6 to 6.9 per 1,000, respectively). Among neonatal deaths, significant proportional increases in extreme prematurity and low birth weight were found (p < 0.001). Conclusions. Neonatal mortality has continued its slow and steady decline in Peru between 2007 and 2021, with a persistent pro-rich pattern of inequality across regions, and disproportionate concentration of deaths in the highlands. During COVID-19 years, the NMR national trend did not alter its downward course, yet NMR inequalities narrowed, indicating an element of social protection along with the concurrent downward trends in unmet basic needs and monetary poverty and upward trends in health expenditures. These findings, at an ecological level, highlight the need for monitoring health inequalities along with setting averages in order to generate evidence on –and build accountability to– the SDG promise to leave no one behind.