Does renal dysfunction predict mortality after acute stroke? A 7-year follow-up study

The purpose of this study was to investigate renal function as a long-term predictor of mortality in patients hospitalized for acute stroke. This was a cohort study done in a Scottish tertiary teaching hospital. Participants included 2042 (993 male) unselected consecutive stroke patients (mean age, 73 years) admitted to hospital within 48 hours of stroke between 1988 and 1994. Follow-up was up to 7 years. Main outcome measure was all-cause mortality. The total number of deaths at the end of follow-up was 1026. Most subjects (1512) had creatinine or =51.27 mL/min significantly predicted better long-term survival in these stroke patients even after adjustment for confounders (age, neurological score, ischemic heart disease, hypertension, smoking, and diuretic use). Similarly, creatinine > or =119 micromol/L "relative risk (RR), 1.59; 95% confidence interval (CI), 1.32 to 1.92", urea 6.8 to 8.9 mmol/L (RR, 1.34; 95% CI, 1.09 to 1.65) or > or =9 mmol/L (RR, 1.74; 95% CI, 1.42 to 2.13), and ratio of urea to creatinine > or =0.08573 mmol/micromol (RR, 1.24; 95% CI, 1.03 to 1.50) remained significant predictors of mortality after adjustment for confounders. After acute stroke, patients with reduced admission calculated creatinine clearance, raised serum creatinine and urea concentrations (even within conventional reference intervals), and raised ratio of urea to creatinine had a higher mortality risk. This finding may be used to stratify risk and target interventions, eg, the use of angiotensin-converting enzyme inhibitors.