Quantifying antibiotic use in paediatrics: a proposal for neonatal DDDs.

The defined daily dose (DDD) as defined by the World Health Organization (WHO) has been the most frequently used unit of measurement to measure antibiotic use. However, measuring antibiotic use in paediatrics is a problem as the WHO DDD methodology is not applicable in children (aged >1 month) due to the large variation in body weight within this population. Based on the narrow range of body weights in the neonatal population, we therefore aimed to develop a set of neonatal DDDs for antibiotics. Eight well-respected (inter)national sources for dosage recommendations of antibiotics in children and neonates were consulted for the assumed maintenance dose of the ten most frequently used antibiotics in neonatal intensive care units in its main indication for neonates. A set of neonatal DDDs for ten commonly used antibiotics in neonates based on an assumed neonatal weight of 2 kg was proposed. Primarily in children DDDs are not applicable to quantify antibiotic use since there is large variation in body weight. In the neonatal population, however, based on its narrow range of body weights and when access to patient level data is not available, neonatal DDDs can be used as a unit of measurement.

Comparison of antibiotic dosing recommendations for neonatal sepsis from established reference sources.

Background Incorrect dosing is the most frequent prescribing error in neonatology, with antibiotics being the most frequently prescribed medicines. Computer physician order entry and clinical decision support systems can create consistency contributing to a reduction of medication errors. Although evidence-based dosing recommendations should be included in such systems, the evidence is not always available and subsequently, dosing recommendations mentioned in guidelines and textbooks are often based on expert opinion. Objective To compare dosage recommendations for antibiotics in neonates with sepsis provided by eight commonly used and well-established international reference sources. Setting An expert team from our Dutch tertiary care neonatal intensive care unit selected eight well-established international reference sources. Method Daily doses of the seven most frequently used antibiotics in the treatment of neonatal sepsis, classified by categories for birth weight and gestational age, were identified from eight well-respected reference sources in neonatology/pediatric infectious diseases. Main outcome measure Standardized average daily dosage. Results A substantial variation in dosage recommendations of antibiotics for neonatal sepsis between the reference sources was shown. Dosage recommendations of ampicillin, ceftazidime, meropenem and vancomycin varied more than recommendations for benzylpenicillin, cefotaxime and gentamicin. One reference source showed a larger variation in dosage recommendations in comparison to the average recommended daily dosage, compared to the other reference sources. Conclusion Antibiotic dosage recommendations for neonates with sepsis can be derived from important reference sources and guidelines. Further exploration to overcome variation in dosage recommendations is necessary to obtain standardized dosage regimens.

Changes in antibiotic use in Dutch hospitals over a six-year period: 1997 to 2002.

OBJECTIVE: To analyse trends in antibiotic use in Dutch hospitals over the period 1997 to 2002. METHODS: Data on the use of antibiotics and hospital resource indicators were obtained by distributing a questionnaire to all Dutch hospital pharmacies. Antibiotic use was expressed as the number of defined daily doses (DDD) per 100 patient-days and as DDD per 100 admissions. RESULTS: Between 1997 and 2002, the mean length of stay decreased by 18%. The mean number of admissions remained almost constant. Total antibiotic use significantly increased by 24%, from 47.2 in 1997 to 58.5 DDD per 100 patient-days in 2002 (p<0.01), whereas expressed as DDD per admissions it remained constant. Antibiotic use varied greatly between the hospitals. Moreover, the mean number of DDD per hospital of amoxicillin with clavulanic acid, clarithromycin, cefazolin, clindamycin and ciprofloxacin increased by 16, 38, 39, 50 and 52%, respectively. Total antibiotic use was higher in university hospitals than in general hospitals. CONCLUSIONS: Between 1997 and 2002, patients hospitalised in the Netherlands did not receive more antibiotics but, since they remained in the hospital for fewer days, the number of DDD per 100 patient-days increased. For macrolides, lincosamides and fluoroquinolones increases in both DDD per 100 patient-days and in DDD per 100 admissions were observed. It is arguable whether these trends result in an increase in selection pressure towards resistance in the hospitals. Continuous surveillance of antibiotic use and resistance is warranted to maintain efficacy and safety of antibiotic treatment.

An additional measure for quantifying antibiotic use in hospitals.

OBJECTIVES: The number of defined daily doses (DDD) per 100 patient days is often used as an indicator for the selection pressure exerted by antibiotics in the hospital setting. However, this unit of measurement does not fully describe the selection pressure and is sensitive to changes in hospital resource indicators. Additional information is required to facilitate interpretation of this indicator. The number of DDD per 100 admissions could be a valuable additional tool. The aim of this study is to investigate the importance of units of measurement in quantifying antibiotic use data with regards to antibiotic resistance risks. PATIENTS AND METHODS: Trends in antibiotic use in acute care Dutch hospitals between 1997-2001 were studied. Antibiotic use was expressed in DDD per 100 patient days and in DDD per 100 admissions. RESULTS: From 1997 to 2001, total systemic antibiotic use significantly increased from 47.2 to 54.7 DDD per 100 patient days, whereas expressed in DDD per 100 admissions it remained constant. Some individual antibiotics increases in DDD per 100 patient days were not accompanied by increases in DDD per 100 admissions and vice versa. The mean number of total DDD per hospital decreased (not significantly) between 1997 and 2001. The mean number of patient days, admissions and length of stay decreased significantly. CONCLUSIONS: Knowledge of variation in resource indicators and additional expression of the data in DDD per 100 admissions is imperative for a meaningful understanding of observed trends in antibiotic use expressed in DDD per 100 patient days. Further research is needed to determine the correlation between different measures of antibiotic use and the level of antibiotic resistance.