Pulmonary function and 6-min walk test (6MWT) among North African long COVID-19 patients

Abstract

Introduction: Long COVID-19, defined as symptom persistence beyond 3 months without alternative diagnosis after recovery, generates cardiorespiratory sequelae that are not yet well elucidated. This study aimed to assess, through spirometry and 6MWT, deficiency of patients who recovered from COVID-19.

Methods: Eighty patients (age>30 years) were included. Anthropometric (age, body mass index (BMI)), spirometric (FEV1, FVC and FEV1/FVC), and 6MWT (6-min walk distance (6MWD), heart-rate (HR), pulsed haemoglobin saturation in oxygen (SpO2), dyspnoea (visual analogous scale (VAS)) data were collected. Applied definitions were: abnormal 6MWD (< lower limit of normal), desaturation (fall in SpO2>5%), abnormal dyspnoea (VAS after 6MWT>5), chronotropic insufficiency (HR after 6MWT<60%), excessive cardiac response (HR after 6MWT>80%).

Results: Age and BMI medians were 61years and 28.4kg/m², respectively. FEV1, FVC, and FEV1/FVC means±SD were 84±16%, 91±14%, and 0.79±0.08, respectively. 6MWD, HR, and resting VAS means±SD were 571±79m (97±15%), 78±11bpm (46±7%), and 1±1, respectively. After 6MWT, HR and VAS were statistically increased (115±24bpm (67±14%) and 3±2, respectively). Mean resting SpO2 was 96.5±1.9% and it increased significantly to 94.7±4.4% after 6MWT. Ten (12.5%) patients presented desaturation. After 6MWT, 15 (19%), 23 (29%), 11 (14%), and 4 (5%) patients had abnormal 6MWD, chronotropic insufficiency, excessive cardiac response, and abnormal dyspnoea, respectively.

Conclusion: Long COVID-19 patients seem to have altered submaximal aerobic capacity, and are likely to develop long-term pulmonary and cardiac impairments. A respiratory rehabilitation program could help restore this incapacity.