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

Monitoring Antibiotic Consumption in Pediatrics. How Close to Reality Are Days of Therapy and Recommended Daily Dose Methods?

BACKGROUND

Hospitals are advised to monitor antibiotic use. Several approximation methods do exist to perform this task. Adult cohorts can easily be monitored using the defined daily dose method, or its German adaption recommended daily doses (RDD) method, that seems inapplicable in pediatric cohorts due to body weight variations. Guidelines recommend the days of therapy (DOT) method in pediatrics. Still, there is a need for more detailed analysis regarding the performance of both methods.

METHODS

Based on data from 4½ years of our fully computerized patient care data managing system in a combined neonatal and pediatric intensive care unit, we compare the results for DOT and RDD per 100 patient days with exact measurement of antibiotic consumption (individual daily dose per 100 patient days) as internal reference.

RESULTS

The DOT method reflected antibiotic consumption in our cohort on the level of total consumption, subgroups, and agents with almost always high accuracy (correlation with individual daily dose between 0.73 and 1.00). The RDD method showed poor correlation on the level of total consumption (r = 0.21) and fluctuating results on more detailed levels (correlation, 0.01-0.94). A detailed analysis of body weight distribution and ordered packaging sizes of single agents revealed that RDD seems to work well when only one package size of the agent was ordered in our pharmacy.

CONCLUSION

The DOT method is superior to RDD for monitoring antibiotic drug consumption in pediatric cohorts. RDD seems to work satisfactory well for selected antibiotic agents that are administered with little variation in packaging size.

The Kinetics of an Antibiotic Stewardship Intervention: A Quasi-Experimental Study

Introduction

Little is known about the kinetics and different phases of a successful antibiotic stewardship program (ASP) intervention.

Methods

We analyzed the trends of quarterly antibiotic use measured in defined daily dose (DDD)/100 days hospitalization using the Joinpoint Regression Program and interrupted time series analysis to objectively identify shifts in the trends of antibiotic use. We correlated these changes in trends with the introduction of a hospital-wide ASP intervention.

Results

The ASP intervention reduced the overall antibiotic use by 33%, from a prior steady state of 76.5 DDD/100 days hospitalization to a post-intervention steady state of 51.2 DDD/100 days hospitalization (p < 0.001). We identified four distinct phases in the trends: prior steady state (A), early intervention (B), accelerated phase (C), and post steady state (D). From A to B a change of slope (−1.46) [SE 0.37, 95% CI −2.23, −0.69 (p = 0.002)]; B to C, a further decrease of slope (−4.70) [SE 0.64, 95% CI −6.03, −3.37 (p = 0.001)]; between periods C and D, straightening out of the slope (+ 6.84) [SE 0.55, 95% CI 5.70, 7.98 (p < 0.001)] to a new post-intervention steady state. It took 1.5 years after completion of the intervention to reach the new steady state.

Conclusions

We demonstrate that ASP interventions require time to achieve the maximal effect. Successful interventions require physicians to adapt new prescribing behaviors and gain confidence in the change; this adaptation can be a prolonged process and might even take years after the introduction of the ASP. These factors should be considered when planning and implementing ASP interventions.

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.