Location specific risk factors for intracerebral hemorrhage: Systematic review and meta-analysis

OBJECTIVE: To conduct a systematic review and meta-analysis of studies reporting on risk factors according to location of the intracerebral hemorrhage. METHODS: We searched PubMed and Embase for cohort and case-control studies reporting ≥100 patients with spontaneous intracerebral hemorrhage that specified the location of the hematoma and reported associations with risk factors published until June 27, 2019. Two authors independently extracted data on risk factors. Estimates were pooled with the generic variance-based random-effects method. RESULTS: After screening 10,013 articles, we included 42 studies totaling 26,174 patients with intracerebral hemorrhage (9,141 lobar and 17,033 nonlobar). Risk factors for nonlobar intracerebral hemorrhage were hypertension (risk ratio [RR] 4.25, 95% confidence interval [CI] 3.05-5.91, I2 = 92%), diabetes mellitus (RR 1.35, 95% CI 1.11-1.64, I2 = 37%), male sex (RR 1.63, 95% CI 1.25-2.14, I2 = 61%), alcohol overuse (RR 1.48, 95% CI 1.21-1.81, I2 = 19%), underweight (RR 2.12, 95% CI 1.12-4.01, I2 = 31%), and being a Black (RR 2.83, 95% CI 1.02-7.84, I2 = 96%) or Hispanic (RR 2.95, 95% CI 1.69-5.14, I2 = 71%) participant compared with being a White participant. Hypertension, but not any of the other risk factors, was also a risk factor for lobar intracerebral hemorrhage (RR 1.83, 95% CI 1.39-2.42, I2 = 76%). Smoking, hypercholesterolemia, and obesity were associated with neither nonlobar nor lobar intracerebral hemorrhage. CONCLUSIONS: Hypertension is a risk factor for both nonlobar and lobar intracerebral hemorrhage, although with double the effect for nonlobar intracerebral hemorrhage. Diabetes mellitus, male sex, alcohol overuse, underweight, and being a Black or Hispanic person are risk factors for nonlobar intracerebral hemorrhage only. Hence, the term hypertensive intracerebral hemorrhage for nonlobar intracerebral hemorrhage is not appropriate.