High Rates of Excess Antibiotic Dosage Common in Elderly CKD Patients

Incorrect doses of antibiotics are “exceedingly common” in the outpatient care of older adults with chronic kidney disease (CKD), reports the American Journal of Kidney Diseases.

The researchers analyzed data on antibiotic prescriptions in southwestern Ontario, Canada. The analysis included 1464 patients aged 66 years or older with stage 4 or 5 CKD who were prescribed eight common oral antibiotics in January 2003, 2005, 2007, and 2009. Ambulatory laboratories in Ontario began reporting estimated GFR (eGFR) in 2006. The rates of excess dosing of antibiotics requiring dosage adjustment in CKD were analyzed, with comparison of periods before and after eGFR reporting.

Overall, 66.3 percent of prescriptions were for doses higher than guideline-based recommendations. The rate of excessive antibiotic dosing was similar before and after the introduction of laboratory eGFR reporting: 64 and 68 per 100 antibiotic prescriptions, respectively. The study identified 169 prescriptions for nitrofurantoin, which is contraindicated in patients with CKD.

Two-thirds of oral antibiotic prescriptions for older adults with CKD may be at too high a dosage for the patient’s level of kidney function, the results suggest. The introduction of eGFR reporting by laboratories appears to have little or no effect on the rate of excess dosing. More research is needed to identify and address the patient, physician, and system factors responsible for this gap in care for CKD patients [Farag A, et al. Dosing errors in prescribed antibiotics for older persons with CKD: a retrospective time series analysis. Am J Kidney Dis 2014; 63:422–428].