Renal function and effect of early antihypertensive therapy in acute ischaemic stroke: a subgroup analysis of the CATIS-2 trial

Background The role of renal function in patients with acute ischaemic stroke (AIS) receiving blood pressure (BP) lowering therapy remains incompletely understood. In this prespecified subgroup analysis of the CATIS-2 trial, we tested the hypothesis that baseline estimated glomerular filtration rate (eGFR) affects the relationship between early antihypertensive therapy and outcomes in AIS. Methods In the CATIS-2 trial, AIS patients were randomly assigned to early treatment (initiating BP-lowering agents within 24–48 hours of stroke onset) or delayed treatment (withholding such agents until day 8). The composite of functional dependence or death (modified Rankin Scale score ≥3) at day 90 was defined as the primary outcome. The treatment effect was analysed between different baseline eGFR values (<90 versus ≥90 mL/min per 1.73 m²). Results 4685 patients were finally enrolled. Among 1061 patients with eGFR<90, the risk of the primary outcome was higher in early treatment compared with delayed treatment (15.3% vs 10.5%; OR (OR) 1.55, 95% CI 1.07–2.23; p=0.02). In 3624 patients with eGFR≥90, no such difference was observed (10.7% vs 10.2%; OR 1.05, 95% CI 0.85 to 1.30; p=0.63). The interaction was marginally significant (p=0.07). Conclusions The modification effect of renal function on different antihypertensive timing for AIS was not observed. Further, adequately powered studies were warranted. Trial registration number NCT03479554 .