Older adults who start taking nonsteroidal anti-inflammatory drugs (NSAIDs) may have increased risks for acute kidney injury (AKI) and hyperkalemia, according to findings from a new Canadian study published in Nephrology Dialysis Transplantation.

Danielle M. Nash, MD, of McMaster University in Hamilton, and collaborators compared 46,107 new NSAID users (more than a 14-day prescription) with the same number of nonusers aged 66 years or older from Ontario. AKI developed within 30 days in 0.82% of users and 0.59% of nonusers. Hyperkalemia occurred in 0.40% and 0.27%, respectively. Users had significant 41% and 50% increased odds of AKI and hyperkalemia, respectively, compared with nonusers.

Only 15% of people received serum creatinine and potassium testing within the 30-day window, however, so it is likely that the true absolute risks are higher.

The investigators found no association between NSAID use and all-cause mortality, which they attribute to the mild nature of the adverse events. A majority of AKI events (79%) were stage 1 and 63% of hyperkalemia events occurred at serum potassium levels of 5.5 to 6 mEq/L.

“Prescription NSAID use among many older adults may be safe, but providers should use caution and assess individual risk,” Dr Nash and the team stated.

CKD patients are urged to avoid NSAIDs. Although the researchers found no significant relationship between baseline estimated glomerular filtration rate (eGFR), NSAIDs, and AKI risk, they noted that patients with lower eGFR nonetheless have the highest absolute risk for AKI.

The investigators created a model to predict AKI and hyperkalemia and have added older age, male gender, lower baseline eGFR, higher baseline serum potassium, and use of ACE inhibitors, angiotensin receptor blockers, and diuretics to improve discrimination.

“Using our model, clinicians can identify high-risk patients who should either receive serum creatinine and potassium monitoring after initiating NSAIDs or should avoid taking NSAIDs altogether.” The model still requires validation.

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Reference

Nash DM, Markle-Reid M, Brimble KS. Nonsteroidal anti-inflammatory drug use and risk of acute kidney injury and hyperkalemia in older adults: a population-based study. Nephrol Dial Transplant. 2019;34:1145–1154. doi:10.1093/ndt/gfz062