“…The number of patients varied widely, and not all series were large enough to have the statistical power for reliable conclusions. 1,5,[11][12][13][14]16,[31][32][33][34][35][36] The diagnosis of ICH was confirmed by imaging studies or autopsy in a few studies, 2,6,13,15,32,33,37,38 and it is often unclear whether ICH was spontaneous or primary. 3-5,8 -12,14 -16,31-34,39,40 In some studies, cases were identified on the basis of International Classification of Diseases (ICD) discharge codes, 8,9,10,39 whereas others included subarachnoid hemorrhage (SAH) 32 or excluded elderly patients.…”