LOTUS - Long-term pulmonary outcomes after infection with SARS-CoV-2:Dyspnea is poorly explained by reduced lung function

Abstract

Background: Reports of long-lasting pulmonary sequelae after Covid-19 has raised serious concern. Still, little is known about the interplay of lasting lung function (LF) affection and patient-reported dyspnea.

Aims and objectives: To investigate the incidence of decreased LF after hospitalization for Covid-19, and to compare LF measures to patient-reported outcome measures (PROMs).

Methods: Patients hospitalized for PCR confirmed Covid-19 in the Central Denmark Region were invited for follow-up visits 3 and 12 months after discharge including LF tests, six-minute walk test, high-resolution CT scan, and selected PROMs (Medical Research Council for dyspnea (MRC), SF-36, Hospital Anxiety and Depression Score, Fatigue Assessment Score (FAS), Montreal Cognitive Assessment (MoCA)). We present an interim analysis of LF and dyspnea score for the first 80 patients at 3 months follow-up.

Results: We included 80 patients, 44 men (55%), median age 59.3 years (range: 19-88). Mean diffusion capacity (DLCO) was 81.6% (SD: 19.9)). In total, 36 (45.6%) and 15 (19.0%) patients had a DLCO below 80% and 60%, respectively. Median MRC was 2 (range 1-4). There was a weak correlation between MRC and DLCO (Spearman’s r= -0.28, p=0.014). Notably, of 42 patients with normal DLCO, 21 (50%) had MRC score ≥ 2 indicating significant dyspnea.

Conclusions: Considerable patient-reported dyspnea is a common problem 3 months after hospitalization for Covid-19 but is poorly explained by reduced LF measured by DLCO. Though pre-morbid LF among these patients is unknown, our results indicate that post-Covid-19 dyspnea is complex and involves respiratory as well as non-respiratory mechanisms.