Winning Abstracts from the 2012 Medical Student Abstract Competition: Antibiotics in Patients with Chronic Kidney Disease: An Epidemic of Dosing Errors
Author: Alexandra Farag, University of Western Ontario, Class of 2013
Introduction: Antibiotics are frequently misprescribed in patients with chronic kidney disease (CKD) and are implicated in over one third of preventable adverse drug events in these patients. To improve the safety of CKD patients, in January 2006, outpatient laboratories in Ontario, Canada began reporting estimated glomerular filtration rate (eGFR) with adult laboratory serum creatinine tests. We sought to describe the rate of ambulatory antibiotic dosing errors in Southwestern Ontario and examine the impact of eGFR reporting on these errors.
Methods: We linked health administrative data for ambulatory residents in Southwestern Ontario from January 2003 to April 2010. Patients had non-dialytic stage 4 or 5 CKD (eGFR < 30 ml/min/1.73 m2 ) and were 66 years of age or older. We conducted a population-based intervention analysis with time-series modeling on the monthly rate of dosing errors in these patients.
Results: Of the total 1464 prescriptions filled for study antibiotics throughout the study period, 970 (66%) were dosed in excess of guidelines. Nitrofurantoin was prescribed 169 times, despite being contraindicated in patients with creatinine clearance < 60 ml/min. The initiation of eGFR reporting was not associated with a decline in the rate of antibiotic dosing errors. Prior to eGFR reporting the average rate of dosing errors was 636 per 1000 antibiotic prescriptions; after eGFR reporting, the rate of dosing errors was 680 per 1000 antibiotic prescriptions.
Conclusion: Our findings demonstrate that ambulatory antibiotic dosing errors are exceedingly common among non-dialytic stage 4 and 5 CKD patients. Moreover, eGFR reporting has not impacted the rate of these errors at the population level. Further interventions to reduce medication errors in CKD patients may therefore be warranted.