Antimicrobial Defined Daily Dose in Neonatal Population: Validation in the Clinical Practice

Background: Currently, there is no validated method for estimating antimicrobial consumption in the neonatal population, as it exists for adults using Defined Daily Doses (DDD). In neonatology, although there are different methods, each one with advantages and disadvantages, there is no unified criterion for use. The aim of this study is to validate the neonatal DDD designed as a new standardised form of antimicrobial consumption over this population. Methods: The validation of the neonatal DDD, Phase II of the research project, was carried out through a descriptive observational study. Periodic cut-offs were performed to collect antimicrobial prescriptions of neonates admitted to the neonatology and intensive care units of nine Spanish hospitals. The data collected included demographic variables (gestational age, postnatal age, weight and sex), antimicrobial dose, frequency and route of administration. The selection of the optimal DDD value takes into account power value, magnitude obtained from the differences in the DDD, statistical significance obtained by the Wilcoxon test and degree of agreement in the stipulated doses. Results: Set of 904 prescriptions were collected and finally 860 were analysed based on the established criteria. The antimicrobials were mostly prescribed in the intensive care unit (63.1%). 32 different antimicrobials were collected, and intravenous administration was the most commonly used route. Neonatal DDD were defined for 11 different antimicrobials. A potency > 80% was obtained in 7 antibiotics. The 57.1% of the selected DDD correspond to phase I and 21.4% from phase II. Conclusion: DDD validation has been achieved for the majority of intravenously administered antimicrobials used in clinical practice in the neonatal population. This will make it possible to have an indicator that will be used globally to estimate the consumption of antimicrobials in this population, thus confirming its usefulness and applicability.