Proton pump inhibitors and the risk of acute kidney injury in older patients: a population-based cohort study. Antoniou T et al. CMAJ Open 2015;Apr;3:E166-E171.
Previous studies have suggested that use of proton pump inhibitors (PPIs) increases risk of acute interstitial nephritis, especially in elderly patients. Using information from several large computerized databases containing medical information about patients in Ontario, Canada, the authors carried out a population-based cohort study of patients in Ontario aged 66 years and older who were newly prescribed PPIs, compared with matched controls. Patients were followed for 120 days. The main outcome was hospital admission for acute kidney injury (AKI); the secondary outcome was admission for acute interstitial nephritis.
Of the approximately 290,000 patients who started PPIs during the course of the study (April 2002 through November 2011), 1787 were admitted with AKI during the 120 days of follow-up. This constituted a hazard ratio 2.5-3.0 times controls. There was no significant different in hazard ratios among specific individual PPIs.
The limitations inherent in extracting data from a computerized database — adequately discussed by the authors — makes it somewhat unclear how to apply these results to the prescribing of PPIs. But it is important for clinicians to be aware of the association between PPIs and AKI. This is not appreciated by many practitioners. It is not unusual for a patient on PPIs admitted for interstitial nephritis to be discharged on the same medicine.