Changes in cardiopulmonary exercise capacity and limitations 3 to 12 months after COVID-19.

RATIONALE: To describe cardiopulmonary function during exercise 12 months after hospital discharge for COVID-19, assess the change from 3 to 12 months, and compare the results with matched controls without COVID-19. METHODS: In this prospective, longitudinal, multicentre cohort study, hospitalized COVID-19 patients were examined with a cardiopulmonary exercise test (CPET) 3 and 12 months after discharge. At 3 months 180 performed a successful CPET, and 177 at 12 months (mean age 59.3 years, 85 females). The COVID-19 patients were compared with controls without COVID-19 matched for age, sex, body mass index, and comorbidity. Main outcome was peak oxygen uptake (V'O2peak). RESULTS: Exercise intolerance (V'O2peak <80% predicted) was observed in 23% at 12 months, related to circulatory (28%), ventilatory (17%), and other limitations including deconditioning, and dysfunctional breathing (55%). Estimated mean difference between 3 and 12 months showed significant increases in V'O2peak % predicted (5.0 percent points (pp), 95% CI (3.1 to 6.9), p<0.001), V'O2peak·kg-1% predicted (3.4 pp, (1.6 to 5.1), p<0.001), and oxygen pulse % predicted (4.6 pp, (2.5 to 6.8), p<0.001). V'O2peak was 2440 mL min-1 in COVID-19 patients compared to 2972 mL min-1 in matched controls CONCLUSIONS: One year after hospital discharge for COVID-19, the majority, 77%, had normal exercise capacity. Only every fourth had exercise intolerance and in these circulatory limiting factors were more common than ventilatory. Deconditioning was common. V'O2peak and oxygen pulse improved significantly from 3 months.