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

Abstract

Background and Purpose-The purpose of this study was to investigate renal function as a long-term predictor of mortality in patients hospitalized for acute stroke.

Methods-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.

Results-The total number of deaths at the end of follow-up was 1026. Most subjects (1512) had creatinine < 124 mumol/L. The mean calculated creatinine clearance was 54.8 mL/min (SD, 23 mL/min). Renal function indexes were analyzed by quartiles with Cox proportional-hazards model. Stroke survivors had higher calculated creatinine clearance and lower serum creatinine, urea, and ratios of urea to creatinine. Calculated creatinine clearance greater than or equal to51.27 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 greater than or equal to119 mumol/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 greater than or equal to9 mmol/L (RR, 1.74; 95% CI, 1.42 to 2.13), and ratio of urea to creatinine greater than or equal to0.08573 mmol/mumol (RR, 1.24; 95% CI, 1.03 to 1.50) remained significant predictors of mortality after adjustment for confounders.

Conclusions-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.

C1 Ninewells Hosp & Med Sch, Dept Med, Stroke Studies Ctr, Dundee DD1 9SY, Scotland.

Ninewells Hosp & Med Sch, Dept Clin Pharmacol & Therapeut, Dundee DD1 9SY, Scotland.

Ninewells Hosp & Med Sch, Dept Biochem Med, Dundee DD1 9SY, Scotland.

Ninewells Hosp & Med Sch, Dept Epidemiol & Publ Hlth, Dundee DD1 9SY, Scotland.

Ninewells Hosp & Med Sch, Cardiovasc Epidemiol Unit, Dundee DD1 9SY, Scotland.

Inonu Univ, Fac Med, Turgut Ozal Med Ctr, Dept Phys Med & Rehabil, Malatya, Turkey.