Propensity Scores and Preventive Drug Use in the Elderly

描述（由申请人提供）：使用处方药和非处方药预防慢性疾病是老年人护理的一个核心特征。评估老年人慢性疾病药物预防有效性的随机对照试验非常昂贵，需要很长时间来设计和实施，并且由于参与者的选择、治疗持续时间较短以及在试验过程中发生的治疗方法变化，可能具有有限的推广能力。然而，关于药物的有益和有害影响的非实验研究，包括基于行政数据的研究，往往是唯一可用的数据，经常被批评为产生有偏见的结果。因此，在评估老年患者用药的预防效果的观察性研究中，开发和应用适当的方法来减少偏倚是至关重要的。倾向评分（ps）是一种越来越多地用于解决非实验研究中的混淆技术。在评估药物和医疗程序有效性的非实验研究中，PSs通常被认为优于传统分析。由RO1 AG023178资助，我们评估了倾向分数（PS）在真实数据集和广泛模拟中的局限性和优势，并自2005年以来开发了基于PS的新型分析技术。我们在主要的国际流行病学、药物流行病学、生物统计学和统计学会议上通过口头报告（28）、海报（16）和研讨会/专题讨论会(4)以及一系列27份出版物传播了我们的结果，其中9份发表在排名最高的流行病学期刊（美国流行病学杂志）上。我们的研究重点是药物治疗的有益和有害影响的非实验研究的主要问题之一，即不可测量的混杂问题。我们之前已经开发了一种创新的方法，从结合PS和回归校准（倾向得分校准）的外部验证研究中纳入了主研究中未测量的混杂因素的额外信息。我们最近发表了另一种创新方法来处理由未测量的混杂因素引起的混杂偏倚。这种方法是基于这样的假设，即患者的治疗与预测相反，更有可能有不可测量的混杂因素，如虚弱，导致医生推翻预测的治疗。这是第一篇显示PS方法相对于传统的多变量结果模型在未测量混杂因素方面具有明显优势的论文。第二个竞争延续将建立在我们过去7年的工作基础上，并将其扩展到相同的领域- PSs的局限性和价值，以评估老年患者药物使用的预防效果，研究团队略有变化，同时保持相同的核心研究人员。使用新的数据来源，包括2007年、2008年和2009年的300万医疗保险受益人的大型随机国家样本，我们将重点关注一些未解决的新的和独特的主题，这些主题涉及实施PSs和老年人预防性用药的影响。

DESCRIPTION (provided by applicant): The use of prescription and non-prescription drugs for prevention of chronic diseases is a central feature of the care of older adults. Randomized controlled trials assessing the effectiveness of pharmacoprevention of chronic diseases in older adults are very costly, take a long time to design and implement, and may be of limited generalizability due to selection of participants, shorter duration of treatment, and changes in therapies that occur over the course of the trial. Nonexperimental studies on beneficial and harmful effects of drugs, including studies based on administrative data that often are the only available data, however, have frequently been criticized as producing biased results. It is therefore vital to develop and apply adequate methods to reduce bias in observational studies that assess the preventive effects of medication use in older patients. Propensity scores (PSs) are an increasingly used technique to address confounding in nonexperimental research. PSs are often perceived as superior to conventional analyses in nonexperimental studies assessing the effectiveness of drugs and medical procedures. Funded by RO1 AG023178, we have assessed limitations and advantages of propensity scores (PS) in real datasets and extensive simulations and have developed novel analytic techniques based on PS since 2005. We have disseminated our results by means of oral presentations (28), posters (16), and workshops/symposia (4) at major international epidemiologic, pharmacoepidemiologic, biostatistics, and statistics meetings and in a series of 27 publications, including 9 in the highet ranked epidemiologic journal (the American Journal of Epidemiology). We have focused our research on one of the major problems of nonexperimental research of beneficial and harmful effects of drug treatments, i.e., the problem of unmeasured confounding. We previously had developed an innovative method to include additional information on confounders not measured in the main study from an external validation study combining PS and regression calibration (Propensity Score Calibration). We recently published another innovative method to deal with confounding bias by unmeasured confounders. This method is based on the assumption that patients treated contrary to prediction are more likely to have unmeasured confounders, like frailty, leading the physician to override the predicted treatment. This is the first paper ever showing a clear advantage of PS methods over conventional multivariable outcome models with respect to unmeasured confounders. The second competing continuation will build on our work over the last 7 years and extend it in the same domain - limitations and value of PSs to assess the preventive effects of medication use in older patients with a slightly changed team of researchers while keeping the same core investigators. Using new data sources, including a large random national sample of 3 million Medicare beneficiaries each for the years 2007, 20008, and 2009, we will focus on several unresolved new and distinct topics regarding the implementation of PSs and the effects of preventive drug use in the elderly.