Alexander E. Merkler, MD 

Nadkarni GN, Patel AA, Konstantinidis I, Mahajan A, Agarwal SK, Sunil Kamat S, et al. Dialysis Requiring Acute Kidney Injury in Acute Cerebrovascular Accident Hospitalizations. Stroke. 2015

Acute kidney injury is not an infrequent complication in patients with stroke. Patients with stroke frequently have risk factors for developing acute kidney injury such as: chronic kidney disease, dehydration, infections, use of contrast dye and hypertonic saline. In the current study by Drs. Nadkarni and Patel et al, the authors evaluate the impact of dialysis-requiring acute kidney injury in patients with stroke. 

The authors utilize the Nationwide Inpatient Sample and Healthcare Cost and Utilization Project to identify all patients with stroke from 2002-2011 using International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes. The authors dichotomized patients with stroke into two groups: those who developed dialysis-requiring acute kidney injury (AKI-D), and those who did not (no AKI-D). Mortality and outcomes (as measured by discharge disposition) were compared between the two groups.

Over 4 million patients with stroke were identified. Factors associated with the development of AKI-D were similar for both ischemic stroke and ICH and included: younger age, male sex, African-American race, history of chronic kidney disease, higher comborbidity score, and sepsis during stroke hospitalization. Patients with stroke and AKI-D had a higher risk of mortality, worse discharge disposition, longer hospital-stay, and higher hospital cost. Similar trends were seen for patients with ischemic stroke and ICH. Interestingly there was a two-fold increase in the rate of AKI-D in patients with stroke over the 9-year study period.

Significant limitations include 1) reliance on ICD-9-CM diagnosis codes – therefore the study lacked clinical information such as size and etiology of stroke and 2) lack of information regarding temporal relation between stroke and the development of AKI-D (which came first).

Overall, AKI-D is not an uncommon complication in patients with stroke. AKI-D is associated with higher mortality and worse discharge outcomes in patients with stroke. Further research is needed to better stratify patients with stroke who are at risk for developing AKI-D and to develop methods to prevent this complication.