Supplementary Material for: Comparing Vascular Brain Injury and Stroke by Cranial Magnetic Resonance Imaging, Physician-Adjudication, and Self-Report: Data from the Strong Heart Study

Background: Epidemiologic studies often use self-report as proxy for clinical history. However, whether self-report correctly identifies prevalence in minority populations with health disparities and poor health-care access is unknown. Furthermore, overlap of clinical vascular events with covert vascular brain injury (VBI), detected by imaging, is largely unexamined. Methods: The Strong Heart Study recruited American Indians from 3 regions, with surveillance and adjudication of stroke events from 1989 to 2013. In 2010–2013, all 817 survivors, aged 65–95 years, underwent brain imaging, neurological history interview, and cognitive testing. VBI was defined as imaged infarct or hemorrhage. Results: Adjudicated stroke was prevalent in 4% of participants and separately collected, self-reported stroke in 8%. Imaging-defined VBI was detected in 51% and not associated with any stroke event in 47%. Compared with adjudication, self-report had 76% sensitivity and 95% specificity. Participants with adjudicated or self-reported stroke had the poorest performance on cognitive testing; those with imaging-only (covert) VBI had intermediate performance. Conclusion: In this community-based cohort, self-report for prior stroke had good performance metrics. A majority of participants with VBI did not have overt, clinically recognized events but did have neurological or cognitive symptoms. Data collection methodology for studies in a resource-limited setting must balance practical limitations in costs, accuracy, feasibility, and research goals.

背景：流行病学研究常以自我报告作为临床病史的替代指标。然而，在存在健康差异且医疗服务可及性较差的少数群体中，自我报告能否准确反映其患病率尚不清楚。此外，临床血管事件与影像学检出的隐匿性脑血管损伤（covert vascular brain injury, VBI）之间的关联，目前尚未得到充分研究。
方法：本研究依托强心脏研究（The Strong Heart Study），于1989年至2013年间从3个地区招募美洲印第安人受试者，对卒中事件开展监测与审校确认。2010年至2013年，所有817名年龄介于65至95岁的存活受试者接受了脑部影像学检查、神经病史访谈与认知功能测试。本研究将隐匿性脑血管损伤（VBI）定义为影像学检出的脑梗死或脑出血。
结果：经审校确认的卒中患病率为4%，单独收集的自我报告卒中患病率为8%。51%的受试者检出影像学定义的VBI，其中47%未发生过任何卒中事件。与审校确认结果相比，自我报告的灵敏度为76%、特异度为95%。经审校确认或自我报告存在卒中的受试者，其认知功能测试表现最差；仅通过影像学检出的（隐匿性）VBI受试者则表现为中等水平。
结论：在本社区队列研究中，既往卒中的自我报告具有良好的效能指标。大多数存在VBI的受试者并未发生过显性、临床确诊的卒中事件，但确实存在神经或认知症状。在资源受限的研究场景下，数据收集方法需要在成本、准确性、可行性与研究目标之间寻求平衡。