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.