Supplementary Material for: Percentage of Age-Predicted Cardiorespiratory Fitness Is Inversely Associated with Cardiovascular Disease Mortality: A Prospective Cohort Study

<b><i>Introduction:</i></b> Percentage of age-predicted cardiorespiratory fitness (% age-predicted CRF) is a potentially useful cardiopulmonary exercise testing (CPX) parameter, but there are limited data on its prognostic relevance for adverse cardiovascular disease (CVD) outcomes. We aimed to assess the association of % age-predicted CRF with CVD mortality and the extent to which % age-predicted CRF measurements could improve the prediction of CVD mortality. <b><i>Methods:</i></b> Peak oxygen uptake, used as the measure of CRF, was directly assessed in 2,276 men who underwent CPX. The age-predicted CRF estimated from a regression equation for age was transformed to % age-predicted CRF with the following formula: (achieved CRF/age-predicted CRF) × 100. Hazard ratios (HRs) (95% confidence intervals [CIs]) and measures of risk discrimination for CVD mortality were calculated. <b><i>Results:</i></b> During a median follow-up of 28.5 years, 643 fatal CVDs were recorded. The relationship between % age-predicted CRF and CVD mortality was dose response in nature. In analysis adjusted for conventional risk factors, one standard deviation increase in % age-predicted CRF was associated with a reduced risk of CVD mortality (HR 0.61; 95% CI: 0.56–0.67), which was minimally attenuated on further adjustment for several other confounders (HR 0.71; 95% CI: 0.64–0.78). Addition of % age-predicted CRF to a CVD mortality risk prediction model containing established risk factors significantly improved risk discrimination and reclassification. <b><i>Conclusion:</i></b> Percentage of age-predicted CRF is inversely and independently associated with CVD mortality in a graded fashion and significantly improves the prediction and classification of the long-term risk for CVD mortality beyond established risk factors.

**引言**：年龄预测心肺适能百分比（% age-predicted CRF）是一项颇具临床应用价值的心肺运动试验（cardiopulmonary exercise testing, CPX）参数，但目前针对其在不良心血管疾病（cardiovascular disease, CVD）结局中的预后相关性研究数据仍较为匮乏。本研究旨在探讨年龄预测心肺适能百分比与心血管疾病死亡率的关联，以及该指标对心血管疾病死亡率预测效能的提升价值。
**方法**：本研究纳入2276名接受心肺运动试验的男性受试者，以峰值摄氧量作为心肺适能（cardiorespiratory fitness, CRF）的直接评估指标。通过针对年龄建立的回归方程估算年龄预测心肺适能，并采用公式（实测CRF/年龄预测CRF）×100转换为年龄预测心肺适能百分比。本研究计算了心血管疾病死亡率的风险比（hazard ratio, HR）与95%置信区间（confidence interval, CI），以及相关风险区分度指标。
**结果**：中位随访时长为28.5年，期间共记录到643例心血管疾病死亡病例。年龄预测心肺适能百分比与心血管疾病死亡率之间呈显著剂量反应关系。在校正传统心血管疾病危险因素的分析中，年龄预测心肺适能百分比每提升1个标准差，受试者的心血管疾病死亡风险显著降低（HR=0.61；95%CI：0.56~0.67）；进一步校正其他混杂因素后，该关联仅出现小幅衰减（HR=0.71；95%CI：0.64~0.78）。将年龄预测心肺适能百分比加入包含既定心血管疾病危险因素的死亡预测模型后，可显著提升模型的风险区分度与重分类能力。
**结论**：年龄预测心肺适能百分比与心血管疾病死亡率呈分级负向独立关联，且在现有既定心血管危险因素基础上，可显著改善心血管疾病死亡率的长期风险预测与分类效能。