Background and aim: Whether the benefit of intensive blood pressure (BP)-lowering varies by hematoma location is uncertain in acute intracerebral hemorrhage (ICH). We aimed to determine the heterogeneity of its treatment effect on functional outcome across hematoma location.
Methods: We conducted an individual participant data meta-analysis (IPD) of five randomized controlled trials (INTERACT1-4, and ATACH-II) investigating intensive BP-lowering in acute ICH. ICH location was classified as lobar or deep hemisphere, or infratentorial. The primary outcome was death or disability (modified Rankin scale [mRS] scores 3-6) at 90 days or 6-months (for INTERACT3). The heterogeneity of the treatment effect of intensive BP-lowering on the primary outcome by ICH location was estimated using generalized linear mixed models with trial as a random effect and adjustment for prespecified clinical covariates and a interaction term of ‘treatment-by-location’.
Results: Among 11,288 patients (mean age 62.5 years [SD 12.7]; 4,056 [35.9%] women), ICH location was 1,141 (10.1%) lobar, 9,202 (81.5%) deep, and 945 (8.4%) infratentorial. Compared with deep or infratentorial ICH, lobar ICH occurred in older patients, was less often associated with intraventricular hemorrhage, and had larger hematoma volumes (all p<0.001). The effect of intensive BP-lowering on the primary outcome of death or disability differed by ICH location (p for interaction = 0.033). A benefit was seen only in deep ICH (adjusted odds ratio [OR] 0.81, 95% confidence interval [CI] 0.74-0.89; p<0.001).
Conclusion: Hematoma location modifies the treatment effect of intensive BP-lowering on functional outcome after ICH, with the benefit observed only in deep ICH.