Effect of Baseline Kidney Function on the Risk of Recurrent Stroke and on Effects of Intensive Blood Pressure Control in Patients With Previous Lacunar Stroke: A Post Hoc Analysis of the SPS3 Trial (Secondary Prevention of Small Subcortical Strokes).

Background We conducted a post hoc analysis of the SPS3 (Secondary Prevention of Small Subcortical Strokes) Trial to examine the association of chronic kidney disease (CKD) with recurrent stroke, and to assess whether baseline renal function modifies the effects of intensive systolic blood pressure control in patients with previous stroke. Methods and Results A total of 3020 patients with recent magnetic resonance imaging-defined symptomatic lacunar infarctions were randomized to a systolic blood pressure target of <130 mm Hg versus 130 to 149 mm Hg. Predefined primary outcomes were (all-recurrent) stroke and a composite of stroke, acute myocardial infarction, or all-cause death; secondary outcomes were acute myocardial infarction, all-cause death, and intracerebral hemorrhage individually. Among 3017 patients with baseline estimated glomerular filtration rate measurements, we evaluated, using Cox proportional hazards models, the association of CKD with recurrent stroke and effects of the blood pressure targets on outcomes using baseline estimated glomerular filtration rate both as a categorical and linear variable. Regardless of the randomized treatment, CKD at baseline was significantly associated with an increased risk of the primary cardiovascular composite outcome (hazard ratio, 1.7; 95% CI, 1.4-2.1), and all-recurrent stroke (1.5; 1.1-2.0). However, the effects of the lower systolic blood pressure intervention on the primary outcome were not influenced by baseline CKD status (P for interaction=0.62). Conclusions CKD increases the risk of recurrent stroke by 50% in patients with previous lacunar stroke. We found no definitive evidence that renal dysfunction modifies the effects of systolic blood pressure control in patients with previous stroke. Conclusive evidence for this will require adequately powered studies with moderate-to-advanced CKD. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT00059306.