The Impact of Acute Kidney Injury on Short-term Survival in an Eastern European Population with Stroke

Background: Stroke is one of the leading causes of death and of serious disability with significant impact on patients' long-term survival. The short-term evolution following stroke can associate acute kidney injury (AKI) as a possible complication, frequently overlooked and underestimated in clinical trials. We aimed to describe in an East European cohort (i) the incidence of AKI and its risk factors; (ii) the 30-day mortality and its risk factors and (iii) the relationship between mortality, pre-existent renal function and subsequent AKI.

Methods: A total of 1090 consecutive cases hospitalized-during a 12-month period-with a CT-confirmed diagnosis of stroke, from a distinct administrative region were included. Demographic details, comorbidities, laboratory and outcome data were retrieved from the electronic hospital database. All patients included in the study were followed for 30 days or until death.

Results: The mean age of this population was 66.1 +/- 11.5 years, 49.3% were males, mean glomerular filtration rate (GFR) 68.9 +/- 22.6 ml/min/1.73 m(2). The 30-day mortality rate was 17.2%. One hundred and fifty-eight patients presented with haemorrhagic stroke and 932 patients had ischaemic stroke. Stroke mortality was-14% for ischaemic stroke and almost twice as high for haemorrhagic stroke-36.3%. One hundred fifty-eight (14.5%) patients were classified as developing AKI. The AKI patients were older, had a higher baseline serum creatinine, lower GFR, higher serum glucose, higher prevalence of chronic heart failure and ischaemic heart disease, were more likely to have suffered a haemorrhagic stroke, and had a significantly higher 30-day mortality rate (43.1 vs 12.8%) (P < 0.05 for all). Independent predictors for AKI development in the logistic regression analysis were age, GFR, presence of comorbidities (ischaemic heart disease and chronic heart failure) and type of stroke (Cox and Snell R(2) 0.244; Nagelkerke R(2) 0.431; P < 0.05). In our study, we demonstrated that the occurrence of AKI is not a rare finding in stroke patients. This is the first study to report the incidence of AKI in a distinct geographic population base, in patients with stroke. Baseline renal function emerged as both a significant independent marker for short-term survival after an acute stroke (even after adjustment for baseline comorbidities) and as a risk factor for subsequent AKI.