Association between renal function and clinical outcome in patients with acute stroke

BACKGROUND AND PURPOSE

Data on the association between renal dysfunction and outcome in patients with stroke are controversial and scarce. We investigated the predictors of renal dysfunction upon admission and the association between renal dysfunction and clinical outcome in patients with acute stroke in a hospitalized Chinese population.

METHODS

1,758 acute stroke patients were consecutively enrolled into the study. The estimated glomerular filtration rate (eGFR) was calculated by the Modification of Diet in Renal Disease equation. Reduced estimate of the glomerular filtration rate was defined as eGFR <60 ml/min/1.73 m(2). Multivariate logistical regression was used to evaluate the predictors of renal dysfunction upon admission and to examine the association between renal dysfunction and outcomes. The main outcome measures were death and death/disability (disability defined as modified Rankin Scale score >2) at 12 months after stroke.

RESULTS

Of the included 1,758 cases (ischemic stroke: n = 1,192; hemorrhagic stroke: n = 566), 463 cases had reduced eGFR, which accounted for 26.3% of the total number. The distribution of eGFR upon admission was normal and the mean was 75.87 +/- 38.31 ml/min/1.73 m(2) (ischemic stroke: 75.07 +/- 29.89 ml/min/1.73 m(2); hemorrhagic stroke: 77.57 +/- 51.73 ml/min/1.73 m(2)). There was no significant difference between the two groups (p = 0.285). The independent predictors of eGFR upon admission were age (OR = 1.039, 95% CI = 1.028-1.050), male gender (OR = 0.658, 95% CI = 0.504-0.859), hematocrit on admission (OR = 1.008, 95% CI = 1.003-1.013), history of hypertension (OR = 1.307, 95% CI = 1.034-1.653), history of diabetes (OR = 1.411, 95% CI = 1.012-1.967) and NIHSS scores upon admission (OR = 1.497, 95% CI = 1.286-1.743). After adjustment for confounders, the patients with renal dysfunction had a significantly higher risk of death/disability (OR = 1.864, 95% CI = 1.170-2.970) compared with patients whose eGFR was more than 90 ml/min/1.73 m(2) at the end of the 12th month. Further analysis on type of stroke showed that reduced eGFR was an independent predictor of death/disability at the end of the 12th month in patients with hemorrhagic stroke (OR = 2.353, 95% CI = 1.063-5.209), but not for ischemic stroke (OR = 1.625, 95% CI = 0.881-2.999).

CONCLUSIONS

Our study indicated that more than 1/4 of all patients with acute stroke presented with renal dysfunction. Reduced eGFR on admission is a strong predictor of poor outcome for hemorrhagic stroke but not for ischemic stroke.