MODELING SPATIAL ACCESSIBILITY TO LOWER ENDOSCOPY SERVICES IN THE UNITED STATES

描述（由申请人提供）：结直肠癌（CRC）是美国第四大常见癌症和第二大癌症死亡原因。包括柔性乙状结肠镜和结肠镜在内的下内镜检查已被证明可以通过发现和切除癌前病变和早期发现CRC来降低CRC发生率和CRC特异性死亡率的风险。然而，在50岁或50岁以上的人群中，较低的内窥镜使用率仍然不到60%。先前的研究发现，CRC筛查、发病率和生存率存在显著的地理差异。小区域的社会经济剥夺与crc相关结果相关，但无法解释观察到的crc相关结果的地理差异，这表明其他社区水平的特征导致了crc相关结果的地理差异。获得保健是获得高质量保健的重要先决条件，因此也是健康结果的决定因素。乳房x光检查服务的低空间可达性与晚期乳腺癌的风险增加有关。很少有人知道低内镜服务的空间可达性是否会导致crc相关结果的地理差异。因此，我们将探讨以下假设：CRC筛查、发病率和生存率的地理差异可归因于低内镜服务的空间可达性。研究将解决两个具体目标：(1)使用GIS、医疗保险数据和空间统计模型，计算和绘制美国50个州和华盛顿特区的下内镜服务的小区域空间可达性；(2)检查下内镜服务的小区域空间可达性对CRC相关结果的影响，包括发生CRC的风险、晚期诊断阶段和CRC特异性死亡率。我们将使用三种不同的空间方法，根据使用医疗保险数据进行乙状结肠镜检查或结肠镜检查的医生的位置，量化和绘制小区域内内镜服务的空间可达性。然后，我们将小区域空间可达性测量与来自高质量的NIH-AARP饮食与健康研究（包括566,407人）的数据联系起来，前瞻性地评估空间可达性对低内镜服务对CRC发病率、晚期诊断和CRC特异性死亡率的影响。这是第一个研究下部内镜服务空间可达性的地理差异，并前瞻性评估其对结直肠癌结局的影响的研究。拟议研究的结果将为开发和实施基于证据的多层次干预措施提供证据，以增加下内镜检查的使用，从而改善crc相关的结果。此外，建议的研究将开发一个空间可达性地图，这将有助于地方和国家决策者改善下层内窥镜服务的分配。

DESCRIPTION (provided by applicant): Colorectal cancer (CRC) is the fourth most common cancer and the second leading cause of cancer deaths in the United States. Lower endoscopic examinations including flexible sigmoidoscopy and colonoscopy have been demonstrated to reduce the risks of incident CRC and CRC-specific mortality through detection and removal of precancerous lesions and early detection of CRC. However, lower endoscopy utilization is still less than 60% among persons aged 50 years or older. Previous research identified significant geographic variations in CRC screening, incidence, and survival. Small-area socioeconomic deprivation has been associated with CRC-related outcomes, but was unable to explain the observed geographic disparity in CRC-related outcomes, suggesting that other community-level characteristics contribute to geographic disparities in CRC-related outcomes. Access to healthcare is an important prerequisite to obtaining quality care and thus a determinant of health outcomes. Low spatial accessibility to mammography service has been associated with an increased risk of late-stage breast cancer. Little is known whether spatial accessibility to lower endoscopy services contributes to the geographic variation in CRC-related outcomes. Therefore, we will explore the hypothesis that geographic disparities in CRC screening, incidence and survival are attributable to spatial accessibility to lower endoscopy services. Two specific aims will be addressed: (1) Compute and map small-area spatial accessibility to lower endoscopy services across the United States including 50 states and Washington DC, using a GIS, Medicare data, and spatial statistical modeling, and (2) Examine the effects of small-area spatial accessibility to lower endoscopy services on CRC-related outcomes, including the risks of incident CRC, advanced stage at diagnosis, and CRC-specific mortality. We will use three different spatial approaches to quantify and map small-area spatial accessibility to lower endoscopy services based on the locations of physicians who performed a sigmoidoscopy or colonoscopy using Medicare data. Then, we will link the small-area spatial accessibility measures with data from the high- quality NIH-AARP Diet and Health Study including 566,407 persons to prospectively assess the effects of spatial accessibility to lower endoscopy services on CRC incidence, advanced stage at diagnosis and CRC- specific mortality. This is the first study to examine the geographic disparity in spatial accessibility to lower endoscopy services and prospectively evaluate its effect on CRC outcomes. The results of the proposed study will provide evidence for the development and implementation of evidence-based multilevel interventions to increase lower endoscopy use and thus improve CRC-related outcomes. In addition, the proposed study will develop a spatial accessibility map which will help local and state policy makers improve the allocation of lower endoscopy services.