Supplementary Material for: Predictors of Supratentorial Deep Intracerebral Hemorrhage Volume and Their Effect on Short-Term Mortality in Asians

Background: The volume of intracerebral hemorrhage (ICH) measured at hospital admission is the strongest predictor of clinical outcomes in patients with ICH. Despite the high incidence rate of ICH in Asians, there is lack of data regarding predictors of ICH volume in this ethnic group. The purpose of this study was to determine predictors of deep ICH volume and examine their effect on short-term mortality in Asians. Methods: Hematoma volume was measured using the ABC/2 method. ICH volume was transformed to the natural log scale to normalize distributions for all analyses. We estimated the coefficients of ICH volume based on relevant predictors using multivariable linear regression. We also determined the association between body mass index (BMI) and ICH volume using a regression line and a line determined by a locally weighted scatter plot smoothing. Results: A total of 1,039 patients from 2 twin hospitals in Korea who were admitted with primary spontaneous supratentorial deep ICH over a 12-year period were enrolled in this study. The median ICH volume was 19.7 ml. The average patient age was 59.2, and 62.4% of patients were men. The mean ICH volume showed a gradual, approximately 2% decrease per 1 BMI increase in the current study, after adjusting for all relevant variables (β = -0.024; SE 0.004; p < 0.001). In addition, patients with frequent alcohol consumption showed a 10% increase in mean ICH volume (β = 0.098; SE 0.041; p = 0.016), and patients undergoing warfarin treatment showed a 30% increase in mean ICH volume after full adjustment of all relevant variables (β = 0.296; SE 0.050; p < 0.001). Relative to overweight patients, there was a 47, 11, and 18% increase in admission mean ICH volume in underweight, normal weight and obese patients, respectively. Patients in the first quartile and underweight BMI groups had 1.45-fold (hazard ratio (HR) 1.45; 95% CI 1.03-2.03; p = 0.035) and 1.77-fold (HR 1.77; 95% CI 1.10-2.84; p = 0.019) higher increased risk of death during the first 3 months after ICH, retrospectively. In addition, patients in groups with frequent alcohol consumption and warfarin use both showed a significant association with mortality 90 days after ICH. Conclusions: We demonstrated the association between various predictors and admission ICH volume with short-term mortality in Asians. Further studies are needed to account for these observations and determine their underlying mechanisms.

研究背景：入院时测得的脑内血肿（intracerebral hemorrhage, ICH）体积是ICH患者临床结局的最强预测因子。尽管亚洲人群中ICH的发病率较高，但目前仍缺乏针对该种族群体ICH体积预测因素的相关数据。本研究旨在明确幕上深部ICH体积的预测因素，并探讨其对亚洲人群短期死亡率的影响。

研究方法：采用ABC/2法计算血肿体积。为使所有分析的分布趋于正态，将ICH体积进行自然对数转换。基于相关预测因子，通过多变量线性回归估算ICH体积的回归系数。此外，通过回归线与局部加权散点图平滑（locally weighted scatter plot smoothing）拟合得到的直线，分析体重指数（body mass index, BMI）与ICH体积之间的关联。

研究结果：本研究共纳入12年间在韩国两家姊妹医院收治的1039例原发性自发性幕上深部ICH患者。受试者的ICH体积中位数为19.7 ml，平均年龄为59.2岁，男性患者占比62.4%。在校正所有相关变量后，本研究中BMI每升高1个单位，平均ICH体积约呈2%的渐进式下降（β=-0.024；标准误（standard error, SE）=0.004；p<0.001）。此外，在完全校正所有相关变量后，频繁饮酒患者的平均ICH体积升高10%（β=0.098；标准误SE=0.041；p=0.016），接受华法林治疗的患者平均ICH体积升高30%（β=0.296；标准误SE=0.050；p<0.001）。与超重患者相比，体质量过低、体重正常及肥胖患者的入院平均ICH体积分别升高47%、11%及18%。本回顾性研究显示，在ICH发病后前3个月内，BMI处于第一四分位数组与体质量过低组患者的死亡风险分别升高1.45倍（风险比（hazard ratio, HR）=1.45；95%置信区间（confidence interval, CI）=1.03~2.03；p=0.035）与1.77倍（HR=1.77；95%CI=1.10~2.84；p=0.019）。此外，频繁饮酒与华法林使用人群均与ICH发病后90天死亡率存在显著关联。

研究结论：本研究明确了亚洲人群中多种预测因子与入院ICH体积及短期死亡率之间的关联。未来仍需开展进一步研究以阐释上述观察结果并明确其潜在机制。