Geography of Amputations Among African Americans

描述（由申请人提供）：非创伤性下肢截肢（LEA）是糖尿病的破坏性后果。65岁及以上的患者约占非创伤性下肢截肢的糖尿病患者的50%。65岁以上的非裔美国人（AA）糖尿病患者截肢的风险增加。在国际上，国与国之间和国家内部的LEAs发生率存在很大的地理差异。在美国，医院转诊地区之间的比较显示出9倍的差异。目前还没有评估较小地理区域（如县）间LEA变化程度的研究。修订探索性研究的目的是：1)表征美国南部3个州65-99岁白人与AA之间糖尿病相关LEA发病率的地理差异；2)探讨美国南部3个州65-99岁白人与AA之间糖尿病相关LEA发病率的地理差异与选定决定因素的关系。这些决定因素的选择基于：1)那些先前提出的解释在LEA率中观察到的地理差异的决定因素；2)新的研究表明，在社会经济条件不利的地区，糖尿病患者的健康状况较差，疾病更多，手术次数更多，可避免的住院率更高；③LEA的危险因素与地理差异无关。研究区域是根据这三个南部州25%或更多的AA人员选择的。根据审稿人的意见，我们提供了更多关于数据质量、有用结果的可能性以及所建议的统计分析方面的细节。

DESCRIPTION (provided by applicant): Nontraumatic lower-extremity amputations (LEA) are a devastating consequence of diabetes. Persons age 65 and older account about 50% of persons with diabetes who had nontraumatic lower-extremity amputations. African Americans (AA) age 65 or older with diabetes are at increased risk of such amputations. Internationally, substantial geographic variation exists in incidence of LEAs between and within nations. In the United States, comparisons between hospital referral regions have shown nine-fold variation. Studies that have assessed the extent of the variation of LEA among smaller geographic areas, such as counties, are not available. The purpose of the revised exploratory study is to: 1) characterize the geographic variation of the incidence of diabetes-related LEA at the county level among AA and white persons age 65-99 in 3 southern states, and 2) explore the association of selected determinants with the geographic variation in diabetes-related incidence of LEA among AA and white persons age 65-99 in 3 southern states. These determinants have been selected based on 1) those previously suggested as explanation of the geographic variation that was observed in LEA rates; 2) emerging research that shows that persons in areas with adverse socioeconomic conditions have lower health status, more disease, more surgical procedures, and a higher rate of avoidable hospitalizations among persons with diabetes; and 3) risk factors for LEA regardless of their geographic variation. The study area has been selected based on the 25 percent or more AA persons in these 3 southern states. Based on the reviewers' comments, we have provided greater detail about the data quality, the likelihood of useful outcomes, and aspects about the proposed statistical analysis. Using an ecological study design, existing data sources will be linked and analyzed, including Medicare claims data (LEA, foot ulcers, peripheral vascular disease, diabetes), Provider of Services file (availability of medical providers), and the 2000 census data (area sociodemographics). We will use county-rates of LEA among AA and white persons age 65-99 with diabetes as the outcome measure. This exploratory study will serve to focus subsequent, more in-depth studies on identifying additional underlying factors that could determine why those with diabetes are at increased risk of LEA in specific geographic areas in a future RO1.