Katsuno Noah, Li Pei Z, Bourbeau Jean, Aaron Shawn, Maltais Francois, Hernandez Paul, Chapman Kenneth R, Walker Brandie, Marciniuk Darcy D, ODonnell Denis D, Sin Don D, Hogg James C, Cheng Michael, Road Jeremy, Tan Wan C
University of British Columbia, Centre for Heart Lung Innovation, St Paul's Hospital, Vancouver, British Columbia, Canada.
Research Institute, McGill University Health Centre, McGill University, Montreal, Quebec Canada.
Chronic Obstr Pulm Dis. 2023 Apr 27;10(2):178-189. doi: 10.15326/jcopdf.2022.0380.
Retaining participants in longitudinal studies increases their power. We undertook this study in a population-based longitudinal cohort of adults with COPD to determine the factors associated with increased cohort attrition.
In the longitudinal population-based Canadian Cohort of Obstructive Lung Disease (CanCOLD) study, 1561 adults > 40 years old were randomly recruited from 9 urban sites. Participants completed in-person visits at 18-month intervals and also were followed up every 3 months over the phone or by email. The cohort retention for the study and the reasons for attrition were analyzed. Hazard ratios and robust standard errors were calculated using Cox regression methods to explore the associations between participants who remained in the study and those who did not.
The median follow-up (years) of the study is 9.0 years. The overall mean retention was 77%. Reasons for attrition (23%) were: dropout by participant (39%), loss of contact (27%), investigator-initiated withdrawal (15%), deaths (9%), serious disease (9%), and relocation (2%). Factors independently associated with attrition were lower educational attainment, higher pack-year tobacco consumption, diagnosed cardiovascular disease, and a higher Hospital Anxiety and Depression Scale score: adjusted hazard ratios (95% confidence interval) were 1.43(1.11, 1.85); 1.01(1.00, 1.01); 1.44(1.13, 1.83); 1.06(1.02, 1.10) respectively.
Identification and awareness of risk factors for attrition could direct targeted retention strategies in longitudinal studies. Moreover, the identification of patient characteristics associated with study dropout could address any potential bias introduced by differential dropouts.
在纵向研究中留住参与者可增强研究效力。我们在一个以人群为基础的慢性阻塞性肺疾病（COPD）成人纵向队列中开展了这项研究，以确定与队列损耗增加相关的因素。
在基于人群的加拿大阻塞性肺病纵向队列（CanCOLD）研究中，从9个城市地点随机招募了1561名40岁以上的成年人。参与者每18个月进行一次面对面访问，并且每3个月通过电话或电子邮件进行随访。分析了该研究的队列保留情况和损耗原因。使用Cox回归方法计算风险比和稳健标准误，以探讨留在研究中的参与者与未留在研究中的参与者之间的关联。
该研究的中位随访时间（年）为9.0年。总体平均保留率为77%。损耗原因（23%）包括：参与者退出（39%）、失去联系（27%）、研究者发起的退出（15%）、死亡（9%）、重病（9%）和搬迁（2%）。与损耗独立相关的因素有较低的教育程度、较高的吸烟包年数、已诊断的心血管疾病以及较高的医院焦虑抑郁量表评分：调整后的风险比（95%置信区间）分别为1.43（1.11, 1.85）；1.01（1.00, 1.01）；1.44（1.13, 1.83）；1.06（1.02, 1.10）。
识别和了解损耗的风险因素可指导纵向研究中有针对性的保留策略。此外，识别与研究退出相关的患者特征可解决因不同退出情况而引入的任何潜在偏倚。
