Statistical analysis
Nominal variables are presented with absolute and relative (%) frequencies, whereas continuous variables are presented with medians and interquartile ranges (IQR). To evaluate differences between units and the effect of intervention, chi-square tests of independence and Mann-Whitney U tests were performed, as appropriate. Stratified analysis by unit and type of unit (PHO units located in pediatric compared to general hospitals) was also performed. All reported p values were based on two-sided tests, and statistical significance was set atp <0.05. All statistical analyses were performed with STATA v.13.0 software (StataCorp., College Station, TX, USA).