Department of Rehabilitation Medicine, St. Marianna University School of Medicine Hospital, Kanagawa, Japan.
Am J Cardiol. 2013 Jun 15;111(12):1767-71. doi: 10.1016/j.amjcard.2013.02.034. Epub 2013 Mar 27.
The purpose of this study was to determine both an association between mortality and physical activity (PA) objectively measured by accelerometer and cutoff values for PA in Japanese outpatients with heart failure (HF). This prospective observational study comprised 170 HF outpatients (mean age, 65.2 years; 77% men). Peak oxygen uptake (VO2) and the relation between ventilation and carbon dioxide production (VE/VCO2 slope) as indices of exercise capacity were measured during cardiopulmonary exercise testing with a cycle ergometer. PA was assessed by accelerometer-measured average step count (steps) per day for 1 week. Study endpoint was cardiovascular-related death. Over an average follow-up of 1,377.1 (median, 1,335) days, 31 cardiovascular-related deaths occurred. Patients were then divided into survivor (n = 139) and nonsurvivor (n = 31) groups. Brain natriuretic peptide level was significantly different between groups. Peak VO2 and steps were also significantly lower and VE/VCO2 slope higher in the nonsurvivors versus survivors. Univariate Cox proportional hazards analysis showed brain natriuretic peptide, peak VO2, VE/VCO2 slope, and steps to be significant prognostic indicators of survival. Multivariate analysis showed PA of ≤4,889.4 steps/day to be a strong and independent predictor of prognosis (hazard ratio: 2.28, 95% confidence interval: 1.31-6.30; p = 0.008). Kaplan-Meier curves after log-rank test showed significant prognostic difference between PA of ≤4,889.4 and >4,889.4 steps/day in the 2 groups (log-rank: 12.19; p = 0.0005). In conclusion, step count as objectively measured by accelerometer may be a prognostic indicator of mortality in Japanese outpatients with HF.
本研究旨在确定通过加速度计客观测量的体力活动 (PA) 与日本心力衰竭 (HF) 门诊患者 PA 的截止值之间的相关性。这项前瞻性观察研究纳入了 170 例 HF 门诊患者（平均年龄 65.2 岁；77%为男性）。在使用功率自行车进行心肺运动测试时，测量了峰值摄氧量 (VO2) 和通气与二氧化碳产生之间的关系 (VE/VCO2 斜率)，作为运动能力的指标。PA 通过 1 周内加速度计测量的平均每日步数 (步数) 来评估。研究终点为心血管相关死亡。在平均 1377.1 天（中位数为 1335 天）的随访期间，31 例发生心血管相关死亡。随后将患者分为存活组（n=139）和非存活组（n=31）。两组间脑钠肽水平存在显著差异。与存活组相比，非存活组的峰值 VO2 和步数显著降低，VE/VCO2 斜率显著升高。单因素 Cox 比例风险分析显示，脑钠肽、峰值 VO2、VE/VCO2 斜率和步数是生存的显著预后指标。多因素分析显示，每天的 PA≤4889.4 步是预后的强有力且独立的预测指标（危险比：2.28，95%置信区间：1.31-6.30；p=0.008）。对数秩检验后的 Kaplan-Meier 曲线显示，两组间 PA≤4889.4 和>4889.4 步/天的患者预后存在显著差异（对数秩检验：12.19；p=0.0005）。总之，加速度计客观测量的步数可能是日本心力衰竭门诊患者死亡率的预后指标。
