Supplementary Material for: Rural-Urban Disparities in Acute Stroke Treatments and Outcomes: A Propensity Score-Matched Analysis of a Nationwide Sample.

Purpose
To investigate the rural-urban differences in acute stroke care in a large cohort of patients hospitalized for acute ischemic stroke (AIS), using a nationwide inpatient sample.

Methods
In this retrospective cohort study, the National Inpatient Sample database was investigated for patients admitted with AIS from 2016 to 2022. Socio-demographics and comorbidities were reviewed. Interventions (rtPA and thrombectomy) were investigated. Outcome measures were prolonged length of stay (PLOS) and mortality. PLOS was defined as length of stay exceeding the 75th percentile of the entire cohort. The cohort was divided in rural and urban location Propensity-score matching (PSM) was applied to balance demographics and comorbidities between the two groups, and outcomes were analyzed between the two matched groups. Multivariable logistic models were used to determine the association between each intervention and rural location. Risk ratio was calculated for PLOS and mortality. Subgroup analyses were performed by age, race, and income. P value as set at 0.05 for all analyses.

Results
Of 897,206 AIS patients, 64,640 (7.2%) were cared for in rural location. Rural group was older (74 [64-83] vs. 71 [60-81], p<0.01) years. Rural group had higher rate of females (51.8% vs. 49%), white racial group (79.8% vs. 64.5%), lower median household income (54.3% vs. 29.1%), and lower private insurance (14.3% vs. 19.2%), p<0.01 for all. After PSM 1:1, rural group independently retained lower odds of rtPA (OR: 0.532, 95%CI: 0.505 - 0.561), lower odds of thrombectomy (OR: 0.074, 95%CI: 0.061 – 0.089), lower risk of PLOS (RR: 0.887, 95%CI: 0.882 – 0.892) and higher risk of mortality (RR: 1.149, 95%CI: 1.122 – 1.177), p<0.01 for all. Older patients in rural setting had lowest odds of interventions, whereas younger, Black, and Hispanic rural patients had highest risk of mortality after AIS.

Conclusions
Socio-demographic differences are present between rural and urban acute stroke care. Profound inequalities exist in the use of reperfusion therapy and outcomes. Great effort is needed by the stroke community to fill this gap and provide equality in acute stroke care.

研究目的
基于全国住院患者样本（National Inpatient Sample, NIS），纳入因急性缺血性脑卒中（acute ischemic stroke, AIS）住院的大型队列患者，探讨城乡急性脑卒中诊疗的差异。

研究方法
本回顾性队列研究纳入2016至2022年因急性缺血性脑卒中住院的患者，数据来源于全国住院患者样本数据库。收集患者的社会人口学特征与合并症信息，分析其接受的干预措施（重组组织型纤溶酶原激活剂（rtPA）与机械取栓术）。主要结局指标为住院时间延长（prolonged length of stay, PLOS）与死亡率。其中住院时间延长定义为住院时长超过全队列的75%分位数。将队列按城乡居住地分为两组，采用倾向得分匹配（propensity-score matching, PSM）平衡两组间的人口学与合并症特征，随后对匹配后的两组患者的结局进行比较。采用多变量logistic回归模型分析每种干预措施与城乡居住地的关联，计算住院时间延长与死亡率的风险比（risk ratio, RR）。按年龄、种族与收入水平进行亚组分析，所有分析均设定检验水准为0.05。

研究结果
本研究共纳入897206例急性缺血性脑卒中患者，其中64640例（7.2%）接受乡村地区的脑卒中诊疗服务。乡村组患者的年龄更高[74岁（四分位间距64~83）vs. 城市组71岁（60~81），P<0.01]；女性占比更高（51.8% vs. 49%），白人占比更高（79.8% vs. 64.5%），家庭中位收入更低（54.3% vs. 29.1%），私人保险覆盖率更低（14.3% vs. 19.2%），以上差异均具有统计学意义（均P<0.01）。经过1:1倾向得分匹配后，乡村组患者接受重组组织型纤溶酶原激活剂治疗的校正比值比（OR）为0.532（95%置信区间：0.505~0.561），接受机械取栓术的校正OR为0.074（95%CI：0.061~0.089），发生住院时间延长的风险比为0.887（95%CI：0.882~0.892），而死亡率的风险比为1.149（95%CI：1.122~1.177），以上差异均具有统计学意义（均P<0.01）。乡村地区的老年患者接受干预措施的几率最低，而年轻、黑人和西班牙裔的乡村患者在发生急性缺血性脑卒中后的死亡风险最高。

研究结论
城乡急性脑卒中诊疗体系存在社会人口学特征差异，再灌注治疗的应用与临床结局均存在显著的不公平性。脑卒中诊疗领域亟需投入更多资源以缩小这一差距，实现急性脑卒中诊疗的公平性。