Environmental Impact on Exacerbations, Chronic Symptoms, and QOL in COPD Patients

描述（由申请人提供）： COPD的患病率接近退伍军人人群的22%，重度COPD患者平均每年发生2.5次急性加重。慢性阻塞性肺病的恶化可以由细菌和病毒呼吸道感染引起，但越来越多的证据表明，空气污染也是一个原因。此前研究空气污染与住院率之间关系的研究都是城市层面的生态研究，没有控制疾病严重程度等患者层面的特征，只关注导致住院的最严重病情恶化。很少有研究评估室外环境空气污染与重要的COPD结果之间的关系，如慢性症状，健康相关的生活质量或体力活动。本研究的总体目的是检查室外空气污染对COPD患者急性加重风险、健康相关生活质量和身体功能的影响。具体目标：该提案的目标是：1）检查长期暴露于室外空气污染是否与COPD患者的病情加重和呼吸道症状相关，2）确定室外空气污染是否与COPD特异性健康相关生活质量下降和体力活动减少相关。研究方法：我们建议对目前入组VA CSP #560（BREATH）的COPD患者进行额外一年的随访，这是一项综合自我管理干预的多中心随机临床试验，入组了425例患者。该研究目前处于观察阶段，将于2010年9月30日结束。拟议的研究是一个机会，可以继续随访这一独特且特征良好的中重度COPD人群，以收集有关患者急性加重、体力活动和HRQOL的其他数据。患者水平的数据将与空气污染数据和有关建筑环境的数据（包括步行能力和户外时间）相关联。之前评估的COPD症状/结局和HRQOL信息将与额外一年的COPD症状/结局、HRQOL、体力活动、空气污染和建筑环境测量结果相结合。将采用混合效应泊松回归模型来检查（1）空气污染和急性加重率以及污染与建筑环境之间的相互作用，以及（2）空气污染与COPD特异性和一般HRQOL以及体力活动之间的关联。将针对重要协变量（包括社会经济状况和COPD疾病严重程度）调整模型。结论：这项研究的结果将大大促进我们对环境空气污染对急性加重、HRQOL和PA的影响的理解。研究结果将为患者提供咨询数据，改善自我管理计划，并更好地制定干预措施，以增加体力活动并改善COPD患者的生活质量。 公共卫生相关性： 自我管理计划可能会减少退伍军人COPD的急性加重并改善HRQOL，通过肺康复改善患者的体力活动被认为是COPD治疗的关键组成部分。自我管理教育是帮助COPD患者管理疾病和预防加重的一个组成部分。了解空气污染对急性加重、HRQOL和体力活动的影响将使医疗服务提供者能够更好地为患者提供咨询，并提供数据来指导干预措施，以改善COPD退伍军人的体力活动。

DESCRIPTION (provided by applicant): The prevalence of COPD approaches 22% of the Veteran population, and patients with severe COPD experience an average of 2.5 exacerbations per year. COPD exacerbations can be triggered by both bacterial and viral respiratory infections, however increasing evidence suggests that air pollution is also a cause. Prior studies examining the relationship between air pollution and hospitalization rates have been ecologic studies at the city level, and have not controlled for patient-level characteristics such as disease severity, and focused only on the most severe exacerbations that lead to hospitalizations. Few studies have evaluated the relationship between outdoor ambient air pollution and important COPD outcomes such as chronic symptoms, health- related quality of life or physical activity. The overall purpose of this study is to examine the impact of outdoor air pollution on risk of exacerbations, health related quality of life and physical function among patients with COPD. Specific aims: The goal of this proposal are to: 1) examine whether chronic exposure to outdoor air pollution is associated with exacerbations and respiratory symptoms among COPD patients, and 2) determine whether outdoor air pollution is associated with worse COPD-specific health-related quality of life and decreased physical activity. Methods: We propose an additional year of follow-up for COPD patients currently enrolled in VA CSP #560 (BREATH), a multicenter randomized clinical trial of a comprehensive self-management intervention that enrolled 425 patients. The study is currently in observational phase set to end September 30, 2010. The proposed research is an opportunity to continue to follow this unique and well-characterized population with moderate to severe COPD in order to collect additional data on patient exacerbations, physical activity, and HRQOL. Patient-level data will be linked to air pollution data and data regarding the built environment including walk ability and time spent outdoors. Previously assessed information on COPD symptoms/outcomes and HRQOL will be combined with an additional year of measurements on patients' COPD symptoms/outcomes, HRQOL, physical activity, air pollution, and built environment. Mixed effects Poisson regression models will be employed to examine the associations between (1) air pollution and exacerbations rates and the interaction between pollution and the built environment, and (2) air pollution and COPD-specific and general HRQOL as well as physical activity. Models will be adjusted for important covariates including socioeconomic status and COPD disease severity. Conclusions: The results of the proposed study will greatly advance our understanding of the impact of ambient air pollution on exacerbations, HRQOL and PA. The results will provide data to counsel patients, improve self-management programs and to better develop interventions to increase physical activity and improve quality of life in COPD. PUBLIC HEALTH RELEVANCE: Self-management programs may decrease exacerbations and improve HRQOL in COPD among Veterans, and improving patient physical activity through pulmonary rehabilitation is considered a key component of the treatment of COPD. Self- management education is a integral part to helping COPD patients manage their disease and prevent exacerbations. Understanding the impact of air pollution on exacerbations, HRQOL and physical activity will enable providers to better counsel patients, and provide data to guide interventions to improve physical activity among Veterans with COPD.