LAUSR

Background Long-term effects of Coronavirus Disease of 2019 (COVID-19) and their sustainability are of the utmost relevance. We aimed to determine: 1) functional capacity of COVID-19 survivors by cardiopulmonary exercise testing (CPET); 2) characteristics associated with cardiopulmonary exercise testing (CPET) performance; 3) safety and tolerability of CPET. Methods We prospectively enrolled consecutive patients with laboratory-confirmed COVID-19 discharged alive at Azienda Sanitaria Locale-3, Genoa. At 3-month from hospital discharge, complete clinical evaluation, trans-thoracic echocardiography, CPET, pulmonary function test, and dominant leg extension (DLE) maximal strength evaluation were performed. Results From 225 patients discharged from March to November 2020, we excluded 12 incomplete/missing cases, 13 unable to perform CPET leading to a final population of 200. Median percent-predicted peak oxygen uptake (%pVO2) was 88% (78.3–103.1). Ninety-nine(49.5%) patients had %pVO2 below, whereas 101(50.5%) above the 85% predicted value (indicating normality). Of 61/99 patients with reduced %pVO2 but normal anaerobic threshold, 9(14.8%) had respiratory, 21(34.4%) cardiac, and 31(50.8%) non-cardiopulmonary limitation of exercise. One-hundred sixty(80.0%) patients complain at least one symptom, without relationship with pVO2. Multivariate linear regression analysis showed percent-predicted forced expiratory volume in one-second(β = 5.29,p = 0.023), percent-predicted diffusing capacity of lungs for carbon monoxide(β = 6.31,p = 0.001), and DLE maximal strength(β = 14.09,p = 0.008) independently associated with pVO2. None adverse event was reported during/after CPET neither the involved health professionals developed COVID-19. Conclusions CPET after COVID-19 is safe and about 1/3rd of COVID-19 survivors show functional capacity limitation mainly explained by muscular impairment, calling for future research to identify patients at higher risk of long-term effects that may benefit from careful surveillance and targeted rehabilitation.