Renal dysfunction increases the risk of recurrent stroke in patients with acute ischemic stroke

Background and aims: This study investigated risks of short-term (1 and 3 months) and long-term (1-year) recurrent stroke associated with glomerular filtration rate (eGFR) in patients with acute ischemic stroke. Methods: From the Taiwan Stroke Registry data, we identified 45,876 acute ischemic stroke patients from April 2006 to April 2014 and classified them into 4 groups based on the eGFR at admission: ≥ 90, 60–89, 30–59, and <30 mL/min/1.73 m² or on dialysis. The risks of 1-month, 3-month and 1-year recurrent stroke related to the eGFR levels were investigated. Results: Both the risks of short-term and long-term recurrent stroke increased as the eGFR levels declined. The 1-month recurrent incidence rates increased steadily from 0.54 to 0.59, 0.84 and 0.89 per 1000 person-days, as the eGFR declined from ≥90 to 60–89, 30–59, and <30 mL/min/1.73 m² or on dialysis, respectively. Compared to patients with eGFR ≥90 mL/min/1.73 m², the adjusted subhazard ratio of 1-month recurrent stroke decreased from 1.69 (95% confidence interval (CI) = 1.24–2.31) for patients with eGFR < 30 mL/min/1.73 m² or on dialysis to 1.14 (95% CI = 0.91–1.43) for patients with eGFRs of 60–89 mL/min/1.73 m², considering the competing risk of deaths. Similar patterns were also observed for the adjusted HRs of 3-month and 1-year recurrent stroke, but with reduced hazard values, by the corresponding eGFR levels. Conclusions: There is an independent graded association between an increased risk of recurrent stroke and declining eGFR levels in patients with acute ischemic stroke.