Impact of COVID-19 lockdown on exercise capacity in PAH patients

The outbreak of novel coronavirus-19 disease (COVID-19) was classified as a global pandemic thanks to the rapid viral spread, and restrictive policy measures of infection containment, including "lockdown" periods and self-isolation, were first instituted in Belgium from March to June 2020. The consequent reduction in physical activity could have a negative impact on exercise capacity, especially in frail patients with pre-existing chronic diseases, such as pulmonary arterial hypertension (PAH). With the aim to define the impact of COVID-19 lockdown on functional status, we included in our observational analysis clinically stable PAH patients, who had performed at least four consecutive 6-min walking tests (6MWT) during 2019-2020, to compare their exercise performance before and after the lockdown. In the 63 patients included, a comparison between the distance covered at 6MWT after the lockdown period and the pooled mean of the previous three 6MWTs showed a mean reduction of 14 m after the lockdown (p = 0.004). Moreover, the mean distance covered at 6MWT went from 447 m in March 2020 to 434 m in June 2020, with a significant average loss of 13 m (p = 0.024). Our results showed that PAH patients were less performing at 6MWT after 3 months of reduced physical activity, despite constant clinical stability and the absence of signs of disease progression, suggesting that this confounding factor should be kept in mind when evaluating changes in 6MWT during or after COVID-19 pandemic.