Supplementary Material for: Determinants of Physical Activity in Patients with Chronic Obstructive Pulmonary Disease: A 5-Year Prospective Follow-Up Study

Background: Although many studies examined determinants of physical activity in patients with chronic obstructive pulmonary disease (COPD), most were cross-sectional and focused on single determinants only. Objectives: The aim of this study was to determine how COPD patients' physical activity changes over time and to identify the determinants of physical activity using multivariable and longitudinal methods. Methods: In a prospective cohort study, 409 primary care patients with COPD in the Netherlands and Switzerland were followed for up to 5 years. Physical activity was assessed at baseline and every 6 months using the Longitudinal Aging Study Amsterdam Physical Activity Questionnaire (LAPAQ) adapted to a 0- to 23-point scale. We studied the associations between determinants at baseline and patients' long-term physical activity levels using linear mixed models. Results: Unadjusted analysis showed an overall gradual decline in physical activity (0.22 points of the LAPAQ scale every 6 months, 95% CI: 0.17-0.28; p < 0.001). In multivariable analyses, baseline determinants that were independently associated (p ≤ 0.05) with lower long-term physical activity levels included (starting from coefficients with the smallest p value) lower exercise capacity, older age, working, more smoking pack-years, more fatigued, male sex, lower educational levels, previously not in fitness programs, more depressed, lower lung function, lower overall health status, and more prescription drug use. Conclusions: We found that physical activity of COPD patients may decline more than reported in the healthy elderly. Longitudinal analysis identified independent determinants of physical activity, which allows the identification of patients having low physical activity levels and who may benefit from physical activity interventions.

背景：尽管众多研究探讨了慢性阻塞性肺疾病（COPD）患者体力活动的影响因素，但大多数研究仅为横断面研究，且仅关注单一因素。目标：本研究的目的是确定COPD患者体力活动随时间的变化，并利用多元和纵向方法识别体力活动的决定因素。方法：在一项前瞻性队列研究中，对荷兰和瑞士的409名COPD原发性护理患者进行了长达5年的随访。体力活动在基线及每6个月使用经过调整的阿姆斯特丹纵向衰老研究体力活动问卷（LAPAQ）进行评估，量表范围为0至23分。我们利用线性混合模型研究了基线决定因素与患者长期体力活动水平之间的关联。结果：未经调整的分析显示，体力活动呈总体渐进性下降（每6个月LAPAQ量表下降0.22分，95%CI：0.17-0.28；p < 0.001）。在多元分析中，与较低长期体力活动水平独立相关（p ≤ 0.05）的基线决定因素包括（从最小p值系数开始）：较低的运动能力、较高年龄、在职、吸烟年数较多、更加疲劳、男性性别、较低的教育水平、以前未参加健身项目、情绪低落、肺功能较低、整体健康状况较低以及更多处方药物的使用。结论：我们发现，COPD患者的体力活动可能比健康老年人的下降幅度更大。纵向分析确定了体力活动的独立决定因素，这使得识别体力活动水平较低且可能从体力活动干预中受益的患者成为可能。