Study Population
Among a total of 105,994 stroke patients registered from 2006 to 2016 in the TSR, 15,031 were patients with intracerebral hemorrhage (Figure 1). Patients with intracerebral hemorrhage caused by trauma or brain tumors were not registered in this database. We excluded patients younger than 18 years old, and patients without information on dialysis status, body mass index (BMI), systolic blood pressure levels, hemoglobin (Hb) levels, serum cholesterol levels, or serum creatinine levels. Patients who died during hospitalization were not excluded. A total of 4,036 hemorrhagic stroke patients were included in this study and divided into five subgroups by the level of estimated glomerular filtration rate (eGFR): ≥ 90 ml/min/1.73 m2, 60-89 ml/min/1.73 m2, 30-59 ml/min/1.73 m2, 15-29 ml/min/1.73 m2, and < 15 ml/min/1.73 m2 or on dialysis. The eGFR was calculated by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation for each non-dialysis patient21. The CKD-EPI equation, expressed as a single equation, is GFR = 141 × min (Scr/κ, 1)α × max (Scr/κ, 1)-1.209 × 0.993Age × 1.018 [if female] × 1.159 [if black], where Scr is serum creatinine, κ is 0.7 for females and 0.9 for males, α is -0.329 for females and -0.411 for males, min indicates the minimum of Scr/κor 1, and max indicates the maximum of Scr/κ or 1. The etiologies of intracerebral hemorrhage were classified into hypertension and non-hypertensive causes. One-month and one-year mortality rates after intracerebral hemorrhage were evaluated by the eGFR levels.