Chronic kidney disease and risk of death during hospitalization for stroke

Abstract

Background: Chronic kidney disease (CKD) is associated with higher stroke incidence, but little is known about the impact of CKD on mortality during stroke hospitalization, especially by CKD stage and index stroke type. This study assessed the effect of prevalent CKD on risk of dying in the hospital after a stroke.

Methods: Data were obtained from all US states that contributed to the Nationwide Inpatient Sample. All patients identified by the International Classification of Diseases, Ninth Revision procedure codes (n=1,127,842) admitted to hospitals between October 2005 and December 2006 with a discharge diagnosis of stroke were included. Independent associations of CKD with in-hospital mortality following stroke were evaluated using multivariable logistic regression.

Results: Of the sample, 64,985 (6%) had CKD, of which 5,785 (9%) died in the hospital. In multivariable analyses, CKD was associated with mortality overall (OR 1.63, 95% CI=1.52-1.75) and regardless of stroke type: ischemic stroke (OR 1.70, 95% CI=1.55-1.86), subarachnoid hemorrhage (OR 1.93, 95% CI=1.45-2.58), intracerebral hemorrhage (OR 1.28, 95% CI=1.10-1.49). Association between CKD and greater mortality was more pronounced in younger age groups (CKD*age interaction: p < 0.0001) and in women vs. men (CKD*sex interaction: p < 0.0001). Higher CKD stage was associated with greater mortality odds, but only with Stages 5 (OR 3.21, 95% CI: 2.09-4.92) and 6 (OR 2.92, 95% CI: 2.62-3.25) was this association of significance.

Conclusions: Presence of CKD is independently associated with higher odds of dying during stroke hospitalization regardless of index stroke type. This adverse association is driven by severe CKD and is more pronounced in relatively younger persons and women.