Six Minute Walk Test changes during outpatient rehabilitation in individuals Post-COVID with and without moderately severe to severe depression symptoms

Research Objectives: To explore Six Minute Walk Test (6MWT) improvements in individuals with and without moderately severe to severe depression symptoms.

Design: Retrospective longitudinal study.

Setting: Two multidisciplinary Post-COVID clinics in the USA.

Participants: 32 adults [mean age 54.9 (14.2) years; 78% female] who underwent outpatient post-COVID rehabilitation for whom admission depression scores (Patient Health Questionnaire-9; PHQ-9) and admission and discharge 6MWT scores were documented.

Interventions: Participants received standard multidisciplinary outpatient therapy. Depression and 6MWT evaluated using established procedures. Minimally clinically important difference of 54m (threshold used for individuals with pulmonary disease) used to define 6MWT improvement.

Main Outcome Measures: 6MWT distance change.

Results: At admission, 34.4% of participants (n= 11) were classified as exhibiting moderately severe to severe depression symptoms (PHQ9 ≥ 15). Normalized 6MWT distances did not vary significantly between those with and without moderately severe to severe depression at admission (65.1%N vs. 60.3%N) or discharge (73.5%N vs. 74.0%N), nor did mean normalized 6MWT improvements (8.4%N vs. 13.7%N). However, the proportion of individuals achieving a clinically significant 6MWT distance improvement (i.e., >54m) was significantly lower in individuals with vs. without moderately severe to severe depression symptoms (27.3% vs. 66.7%) [X2(1, 32)=4.499; p=0.034].

Conclusions: Depression is common in individuals undergoing post-COVID outpatient rehabilitation and may limit treatment benefits. In this pilot study, neither group, on average, achieved normal 6MWT distances. Further, individuals with greater depression symptoms were less likely to achieve clinically significant improvements in 6MWT distance compared to counterparts. Further study is needed to explore relationships between mental health and physical rehabilitation outcomes.

Author(s) Disclosures: This work was developed through subawards from the U.S. Department of the Treasury (FAINs SLFRP1965 and SLFRP1615; PI: Burnfield).