Hospital Volume and Quality of Care

产品说明：医院里的医生治疗了大量患有类似疾病的患者，他们将获得最有效治疗方法的经验。人们会认为这种专业知识应该反映在更好的健康结果中（实践使完美假设）。然而，使用观察数据，选择偏倚出现，因为患者更喜欢感知的“更好”的医院，在数量和结果之间产生虚假的相关性（选择性转诊假设）。全面了解医院数量与健康结果之间的关系是一项高度优先的政策。虽然医院的数量和护理质量之间的正相关关系已被大量的医疗干预，很少有研究试图控制的选择性偏见，由于选择性转诊。拟议的研究将利用两个现有的数据库，以更好地了解医院数量和健康结果之间的关系的原因。该项目有以下两个具体目标：1）获得医院数量对健康结果影响的无偏估计。2)分析自技术采用以来的时间和积累的经验对护理质量的影响。 我们的数据将来自心血管合作项目（CCP）（1994年至1995年因急性心肌梗死（AMI）入院的医疗保险患者样本），我们将使用全国不耐烦样本（NIS）来衡量医院数量和采用特定技术的年份。CCP数据在研究医院数量与健康结果之间的关系方面有几个优势：1）它是一个大的和全国代表性的样本，2）它包含了医院后死亡率和再入院的信息，3）它包含了非常详细的信息，在入院时的疾病严重程度和所进行的程序，4）它包含患者的邮政编码，这将为我们提供比以前的研究更好的工具。

DESCRIPTION: Physicians in hospitals that treat a large number of patients with a similar condition will gain experience about the most effective treatments. One would assume this expertise should be reflected in better health outcomes (practice-makes-perfect hypothesis). However, using observational data, a selection bias arises since patients prefer the perceived "better" hospital, creating a spurious correlation between volume and outcomes (selective-referrals hypothesis). Gaining a comprehensive understanding of the relationship between hospital volume and health outcomes commands a high policy priority. Although the positive relationship between hospital volume and quality of care has been well documented for a large number of medical interventions, few studies have tried to control for the selectivity bias due to selective referrals. The proposed research will take advantage of two existing data bases to better understand the causes of the relationship between hospital volume and health outcomes. This project has the following two specific aims: 1) Obtain unbiased estimates of the effect of hospital volume on health outcomes. 2) Analyze the effects of time since technology adoption and accumulated experience on quality of care. Our data will come from the Cooperative Cardiovascular Project (CCP) (a sample of Medicare patients who were admitted for an acute myocardial infarction (AMI) between 1994 and 1995) and we will use the Nationwide Impatient Sample (NIS) to measure hospital volume and the year when a particular technology was adopted. The CCP data has several advantages to study the relation between hospital volume and health outcomes: 1) It is a large and nationally representative sample, 2) It contains information on post-hospital mortality and readmissions, 3) it contains very detailed information on the severity of illness at admission and the procedures performed, 4) it contains the patient's zip code which will provide us with better instruments than previous studies.