Strong association between Apgar score at 5 minutes and neonatal survival among at-risk neonates

Objective To assess the association between 5-minutes Apgar score and neonatal survival among at-risk neonates. Design Retrospective survival analysis. Setting Ecuadorian neonates who died at ≤28 days of life. Patients We analyzed the nationwide neonatal deaths registered by the Ministry of Public Health of Ecuador between January 2014 to September 2017. Main outcome measures We performed a survival analysis and estimated adjusted hazard ratios (HR) per each 5-minutes Apgar score stratum , by Cox proportional hazards models. Results We included in the study 2893 neonates, 1380 (48%) were female and had a median (P25 to P75) gestational age at birth of 31 (27 to 36) weeks. On univariate analyses, the median survival time in days of life was significantly longer per each increase in the 5-minutes Apgar score, as follows: 0.2 days for ≤4 points, 2 days for 5 points, 2.9 days for 6 points, 3.1 days for 7 points, 3.8 days for 8 points, 4.4 days for 9 points, and 5.5 days for 10 points. On multivariate analyses, and after adjusting for individual and contextual variables, and considering an Apgar score of 9 to 10 points as the reference, the HR was 32% (95% CI: 27% to 37%) higher per each decrease in the Apgar score category of two-to-three points ( p-value for trend <0.01). Conclusions There is a strong direct association between Apgar score at 5 minutes and neonatal survival in neonates considered at-risk. This association is independent of gestational age and other neonatal determinants of neonatal mortality.