Supplementary file 1_Community resilience and stroke outcomes in older adults: beyond rural-urban classifications.xlsx

IntroductionStroke is a leading cause of death and disability among older U. S. adults, with persistent geographic disparities. The role of community resilience, and whether its effects differ across changing rural-urban county trajectories, remains underexamined. This study assessed associations between county-level resilience domains and stroke burden among Medicare fee-for-service beneficiaries aged ≥65 and evaluated variation across stable rural, stable urban, rural-to-urban transitioning, and urban-to-rural deurbanizing counties.
MethodsThis ecological study analyzed 3,100 U. S. mainland counties. County trajectories were derived using 2010 and 2020 Rural-Urban Continuum Codes. Resilience was measured using the Baseline Resilience Indicators for Communities (BRIC) index, which includes social, economic, community capital, institutional, infrastructure, and environmental domains. Correlation and multivariable regression models examined associations between resilience domains and stroke burden (2022). Spatial clustering was assessed using Local Indicators of Spatial Association (LISA), which identifies high-high and low-low groupings where counties have values similar to their neighbors.
ResultsMean stroke burden (% of Medicare FFS beneficiaries). was 5.5% (SD = 1.47) and increased by 2.17 percentage points (SD = 1.90) from 2014 to 2022, with the highest levels in urban and deurbanizing counties. Social resilience was consistently associated with lower stroke burden across all trajectories. Infrastructure and environmental resilience were also inversely associated, though effects varied by trajectory. Economic and institutional resilience were positively associated with burden in the overall and rural models. In multivariable analyses, social resilience remained the strongest negative predictor across all strata and the only consistently significant domain in transitioning and deurbanizing counties. Spatial analysis showed high-high stroke clusters in the Southeast (Stroke Belt), while most resilience domains exhibited low-low clusters in the same regions.
ConclusionSocial and infrastructural resilience were the most consistent protective factors for stroke burden among older adults, whereas positive associations for economic and institutional domains likely reflect contextual or measurement characteristics. Overlapping low-resilience and high-stroke clusters in the Stroke Belt highlight the need for trajectory-based, resilience-informed strategies to reduce geographic disparities among older Medicare beneficiaries.

引言
卒中是美国老年成人死亡与致残的首要诱因之一，且存在持续的地理分布差异。目前对于社区韧性的作用，以及其效应是否随县域城乡变迁轨迹的不同而存在差异，仍未得到充分研究。本研究评估了≥65岁的美国医疗保险按服务付费参保人群中，县域层面韧性维度与卒中负担之间的关联，并分析了稳定农村县域、稳定城市县域、城乡转型县域以及城市向农村逆转型县域中该关联的异质性。

方法
本项生态研究共纳入美国本土3100个县域。基于2010年与2020年城乡连续体代码推导县域变迁轨迹。采用社区基础韧性指标（Baseline Resilience Indicators for Communities, BRIC）量表衡量韧性水平，该量表涵盖社会、经济、社区资本、制度、基础设施及环境六大韧性维度。通过相关性分析与多变量回归模型，探究韧性维度与2022年卒中负担之间的关联。采用空间自相关局部指标（Local Indicators of Spatial Association, LISA）分析空间聚集性，该方法可识别县域与其邻域数值相似的高-高聚集与低-低聚集区域。

结果
参保人群平均卒中负担（占医疗保险按服务付费参保人的比例）为5.5%（标准差=1.47）；2014年至2022年间，卒中负担平均升高2.17个百分点（标准差=1.90），其中城市县域与逆转型县域的卒中负担水平最高。在所有变迁轨迹类型的县域中，社会韧性均与更低的卒中负担显著相关。基础设施韧性与环境韧性同样呈负相关关联，但其效应随县域轨迹类型不同而存在差异。在全样本与农村县域模型中，经济韧性与制度韧性均与卒中负担呈正相关。多变量分析显示，社会韧性仍是所有分层中最强的负向预测因子，同时也是城乡转型县域与逆转型县域中唯一始终具有统计学显著性的韧性维度。空间分析结果显示，卒中负担的高-高聚集区位于美国东南部（卒中带），而多数韧性维度在该区域呈现低-低聚集特征。

结论
社会韧性与基础设施韧性是老年人群卒中负担最稳定的保护因素，而经济韧性与制度韧性与卒中负担的正相关关联，可能反映了区域背景或测量方法本身的特征。卒中带区域同时存在低韧性与高卒中负担的聚集特征，这提示需要基于县域变迁轨迹、结合韧性建设的干预策略，以缩小老年医疗保险参保人群间的地理健康差异。