[Understaffed nursing shifts and risk-adjusted survival of very preterm infants - an analysis of neonatal intensive care units level 1 in Germany 2019-2023].

Higher nurse-to-patient ratios have been linked to decreased mortality and morbidity. Federal German regulations call for nurse shift staffing requirements in neonatal intensive care units and mandatory reporting of understaffed shifts. What is the relationship between the percentage of understaffed nurse shifts and outcome of very preterm infants?We analyzed data published for 163 hospitals providing level 3 neonatal intensive care in Germany 2019-2023, linking percentages of fully staffed nurse shifts with mortality and major morbidity of preterm infants<1500 g birthweight (gestational age 24⁰/₇ bis 31⁶/₇ weeks).No correlation was found between percentages of fully staffed shifts and survival (Rs=0.008, p=0.918) or survival without major morbidity (Rs=0.050, p=0.529). Hospitals with ≤ 95% fully staffed shifts (n=82), as opposed to>95% (n=81), had higher annual caseloads of preterm infants<1500 g (median [interquartile range] 53 [37-77] vs. 41 [33-55], p=0.001) und higher risk-adapted caseloads (56 [35-77] vs. 42 [30-58], p=0.002) while there was no difference in rates of survival relative to the national average (1.00 [0.99-1.01] vs. 1.00 [0.99-1.01], p=0.722) or survival without major morbidity (1.00 [0.97-1.03] vs. 0.99 [0.97-1.02], p=0.346). There were also no significant differences in outcome with other cut-offs or when comparing the lowest with the highest quartile.In this analysis, percentages of understaffed nurse shifts were unrelated to mortality or major morbidity of very preterm infants.