To the Editor: In a retrospective matched cohort study, Dr Wald and colleagues1 concluded that acute kidney injury (AKI) requiring dialysis was associated with an increased risk of end-stage renal disease but not all-cause mortality. This finding contradicts the conclusions of recent studies demonstrating a significant association between AKI and long-term mortality.2- 4 The selection criteria for both the AKI exposure and control groups in their study might have contributed to this difference, rendering questionable the external validity of the study.
Bihorac A, Schold JD, Hobson CE. Long-term Mortality Associated With Acute Kidney Injury Requiring Dialysis. JAMA. 2010;303(3):229-230. doi:10.1001/jama.2009.1878