Background: current data on the impact of acute illness severity on exercise capacity and ventilatory efficiency of COVID-19 survivors, evaluated at cardiopulmonary exercise test (CPET), are limited.

Methods: in this post-hoc analysis of our previous observational, prospective, cohort study on mechanisms of exercise intolerance in COVID-19 survivors, we aimed at evaluating the impact of acute COVID-19 severity on exercise capacity, pulmonary function testing (PFT) and chest computed tomography (CT) outcomes.

Results: we enrolled 75 patients (18 with mild-to-moderate disease, 18 with severe disease, and 39 with critical disease). Mean (standard deviation – SD) follow-up time was 97 (26) days. Groups showed a similar PFT and CT residual involvement, featuring a mildly reduced exercise capacity with comparable mean (SD) values of peak oxygen consumption as percentage of predicted (83 (17) vs 82 (16) vs 84 (15), p = 0.895) among groups, as well as the median (interquartile range – IQR) alveolar-arterial gradient for O₂ in mmHg at exercise peak (20 (15–28) vs 27 (18–31) vs 26 (21-21), p = 0.154), which was in the limit of normal. In addition, these patients featured a preserved mean ventilatory efficiency evaluated through the slope of the relation between ventilation and carbon dioxide output during exercise (27.1 (2.6) vs 29.8 (3.9) vs 28.3 (2.6), p = 0.028), without a clinically relevant difference.

Conclusions

Disease severity does not impact on exercise capacity in COVID-19 survivors at 3 months after discharge, including a ventilatory response still in the limit of normal.

中文翻译：

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严重程度不会影响 COVID-19 幸存者的运动能力

背景：目前关于急性疾病严重程度对 COVID-19 幸存者运动能力和通气效率影响的数据，通过心肺运动试验 (CPET) 进行评估，是有限的。

方法：在我们之前关于 COVID-19 幸存者运动不耐受机制的观察性、前瞻性队列研究的事后分析中，我们旨在评估急性 COVID-19 严重程度对运动能力、肺功能测试 (PFT) 的影响和胸部计算机断层扫描 (CT) 结果。

结果：我们纳入了 75 名患者（18 名患有轻度至中度疾病，18 名患有严重疾病，39 名患有危重症）。平均（标准差 - SD）随访时间为 97（26）天。各组表现出相似的 PFT 和 CT 残余受累，具有轻度降低的运动能力，峰值耗氧量的均值 (SD) 与预测值的百分比相当 (83 (17) vs 82 (16) vs 84 (15)，p = 0.895 ) 在各组之间，以及 O _{2的中值（四分位数范围 - IQR）肺泡 - 动脉梯度}以运动峰值时的 mmHg 为单位（20 (15–28) vs 27 (18–31) vs 26 (21-21)，p = 0.154），处于正常范围内。此外，这些患者的平均通气效率保持不变，通过运动期间通气与二氧化碳输出量之间关系的斜率进行评估（27.1 (2.6) vs 29.8 (3.9) vs 28.3 (2.6)，p = 0.028），没有临床相关差异。

结论

出院后 3 个月，疾病严重程度不会影响 COVID-19 幸存者的运动能力，包括仍处于正常范围内的通气反应。