Development and validation of a mathematical model to quantify antibiotic consumption in paediatric population: A hospital-based pilot study.

What Is Known And Objectives: A standard drug classification system and a fundamental measurement unit of drug consumption are prerequisites in a healthcare information system for generating quality data on drug use. Globally, the ATC/DDD (Anatomical Therapeutic Chemical Classification/Defined Daily Dose) system recommended by WHO is accepted as the international standard. However, owing to variability in body weight, it cannot be used directly in paediatric population. In our work, we aimed to develop a standard method of quantification of antibiotic consumption in paediatric population using a modified approach of the ATC/DDD system.

Method: We developed a mathematical model in a simulated paediatric cohort (n = 1000) and calculated antibiotic consumption in units of days of therapy (DOT) and DDD/100 patient days (PD). We validated the model in an observational cohort (n = 38) of inpatients admitted in Paediatric Department of a tertiary care centre.

Results: Model simulation showed near perfect positive correlation (R = .99-1.00) between DOT and DDD/100 PD in discrete weight based sub-cohorts (weight 1-10 kg). In the validation cohort, consumption of antibiotics was 121.76 and 33.16 in terms of DOT and DDD/100 PD respectively. Strong positive correlation between the two units (R = .73) was obtained. The correlation was better in predefined age and weight categories as compared to the uncategorised consumption (R = .78-.97). The model was proved validated when weight specific (in sub-cohorts of patients weighing 4, 5, 7 kg) DDD/100 PD and DOT also showed near perfect positive correlation (R = .96-.99).

What Is New And Conclusion: Weight specific DDD/100 PD can be explored further as a tool to standardise the quantification and comparison of consumption of drugs in paediatric population.