Impact on urinary oxalate levels with use of ezetimibe

Area of Science:

• Nephrology
• Urology
• Pharmacology

Background:

• Calcium oxalate stones are the most prevalent type of nephrolithiasis in the United States.
• Previous small studies (<15 patients) suggested ezetimibe, a cholesterol absorption inhibitor, might increase urinary oxalate levels.
• A larger patient sample and multiple urine collections were used to clarify the relationship between ezetimibe and urinary oxalate.

Purpose of the Study:

• To investigate the effect of ezetimibe on urinary oxalate levels in patients evaluated for nephrolithiasis.
• To determine if ezetimibe use increases urinary oxalate and if discontinuation reduces it.

Main Methods:

• Retrospective review of patients with nephrolithiasis and documented ezetimibe use at Mayo Clinic Florida (01/2018-04/2019).
• Analysis of 117 24-hour urine collections from 30 patients, comparing oxalate levels on and off ezetimibe.
• Statistical adjustment for age and sex to assess the difference in urinary oxalate levels.

Main Results:

• The mean urinary oxalate level was 39.86 mg off ezetimibe and 40.45 mg on ezetimibe.
• After adjusting for age and sex, the estimated difference in urinary oxalate was 1.239 mg (p=0.93), indicating no significant change.
• A subset analysis of six patients also showed no consistent or significant change in 24-hour urinary oxalate levels with ezetimibe use.

Conclusions:

• Ezetimibe use in patients with nephrolithiasis does not show a clear association with increased urinary oxalate levels.
• The findings do not support a significant impact of ezetimibe on urinary oxalate, contrary to some prior smaller studies.
• Further research may be needed, but current evidence suggests ezetimibe is unlikely to be a major contributor to hyperoxaluria in this patient population.