Association of Angiotensin-Converting Enzyme Inhibitor or Angiotensin Receptor Blocker Use With Outcomes After Acute Kidney Injury

IMPORTANCE Patients with acute kidney injury (AKI) are at an increased long-term risk of death. Effective strategies that improve long-term outcomes in patients with AKI are unknown. OBJECTIVE To evaluate whether the use of angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) after hospital discharge is associated with better outcomes in patients with AKI. DESIGN, SETTING, AND PARTICIPANTS This retrospective cohort study used data from the Alberta Kidney Disease Network population database to evaluate 46 253 adults 18 years or older with an episode of AKI during a hospitalization between July 1, 2008, and March 31, 2015, in Alberta, Canada. All patients who survived to hospital discharge were followed up for a minimum of 2 years. EXPOSURES Use of an ACEI or ARB within 6 months after hospital discharge. MAIN OUTCOMES AND MEASURES The primary outcome was mortality; secondary outcomes included hospitalization for a renal cause, end-stage renal disease (ESRD), and a composite outcome of ESRD or sustained doubling of serum creatinine concentration. An AKI was defined as a 50% increase between prehospital and peak in-hospital serum creatinine concentrations. Propensity scores were used to construct a matched-pairs cohort of patients who did and did not have a prescription for an ACEI or ARB within 6 months after hospital discharge. RESULTS The study evaluated 46 253 adults (mean [SD] age, 68.6 [16.4] years; 24 436 [52.8%] male). Within 6 months of discharge, 22 193 (48.0%) of the participants were prescribed an ACEI or ARB. After adjustment for comorbidities, ACEI or ARB use before admission, demographics, baseline kidney function, other factors related to index hospitalization, and prior health care services, ACEI or ARB use was associated with lower mortality in patients with AKI after 2 years (adjusted hazard ratio, 0.85; 95% CI, 0.81-0.89). However, patients who received an ACEI or ARB had a higher risk of hospitalization for a renal cause (adjusted hazard ratio, 1.28; 95% CI, 1.12-1.46). No association was found between ACEI or ARB use and progression to ESRD. CONCLUSIONS AND RELEVANCE Among patients with AKI, ACEI or ARB therapy appeared to be associated with lower mortality but a higher risk of hospitalization for a renal cause. These results suggest a potential benefit of ACEI or ARB use after AKI, but cautious monitoring for renal-specific complications may be warranted.