A Novel Metric System to Quantify Antibiotic Consumption in Paediatric Population: A Hospital Based, Biphasic Pilot Study.

Background: The Anatomical Therapeutic Chemical Classification / Defined Daily Dose (ATC/DDD) system recommended by World Health Organization is accepted worldwide as the standard method of quantification of drug consumption. However, owing to individual variation in body weight, the ATC/DDD system cannot be used for comparison across paediatric population.

Objective: This study aimed to develop a novel metric system for standard quantification of antibiotic consumption in paediatric population.

Method: The standard unit of drug quantification in adult population is DDD/100 patient days (PD). We conceived a new unit of DDD/1000 kg-days (KD) where KD is the product of the body weight and length of hospital stay of an individual patient. We simulated the quantification and comparison of drugs in a computer model of five virtual paediatric hospitals (H1 to H5, n=100, 200, 100, 100, 100 respectively). We re-applied the metric system on two, real world, hospital-based, time cohorts (TC) (TC18, n=38 and TC19, n=47) of 2 weeks each, in two consecutive years.

Results: The body weights (mean±SD) in H1-H5 were 5.7±3.0, 5.7±2.8, 25.3±8.5, 20.6±11.7 and 19.8±11.4 kg, respectively. The antibiotic consumption in terms of DDD/100 PD and DDD/1000 KD in the five hospitals was 1.26, 1.20, 5.52, 4.41 and 2.00, and 2.24, 2.14, 2.22, 2.17 and 1.06 respectively. In TC18 and TC19, the mean body weight, DDD/100 PD and DDD/1000 KD were 12.24±13.17, 30.93, 20.34 and 19.51±12.28, 11.99, 6.23, respectively.

Conclusion: DDD/1000 kg-days is a potential standard unit for drug quantification in paediatric population independent of weight distribution and size of the study sample. The universal application and comparison across diverse samples can generate useful information for resource allocation, anti-microbial stewardship, disease burden and drug use, and can help in taking policy decisions to improve healthcare delivery in the paediatric population.