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。包括乙状结肠镜检查和结肠镜检查在内的低位内镜检查已被证明可以通过检测和切除癌前病变以及早期发现CRC来降低CRC事件和CRC特异性死亡率的风险。然而，在50岁或50岁以上的人群中，内镜检查的使用率仍低于60%。 以前的研究发现，CRC筛查、发病率和生存率存在显著的地理差异。小区域社会经济贫困与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，这表明其他社区层面的特征有助于CRC相关结果的地理差异。获得医疗保健是获得优质护理的一个重要先决条件，因此也是健康结果的一个决定因素。乳房X光检查服务的空间可及性低与晚期乳腺癌风险增加有关。目前尚不清楚胃镜检查服务的空间可达性是否会导致CRC相关结局的地理差异。因此，我们将探讨这一假设，即CRC筛查、发病率和生存率的地理差异归因于内镜服务的空间可及性。将处理两个具体目标：（1）使用GIS、医疗保险数据和空间统计建模，计算并绘制美国包括50个州和华盛顿特区在内的下段内窥镜检查服务的小区域空间可达性，以及（2）检查下段内窥镜检查服务的小区域空间可达性对CRC相关结局的影响，包括CRC事件的风险、诊断时的晚期、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，量化和绘制下段内窥镜服务的小区域空间可达性。然后，我们将小区域空间可达性指标与高质量的NIH-AARP饮食和健康研究（包括566，407人）的数据相联系，以前瞻性评估内镜检查服务的空间可达性对CRC发病率、诊断时的晚期和CRC特异性死亡率的影响。这是第一项研究，以检查在空间上的差异，以较低的内镜服务，并前瞻性地评估其对结直肠癌的结果。拟议研究的结果将为制定和实施基于证据的多层次干预措施提供证据，以增加下段内窥镜检查的使用，从而改善CRC相关结局。此外，拟议的研究将制定一个空间可达性地图，这将有助于地方和州的政策制定者改善下消化道内镜服务的分配。

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.