Trajectories of Physical Disabilities Over 6 Months in Patients With Long COVID

Understanding the long-term impact of long COVID on physical function and health-related quality of life (HRQoL) is essential to guide clinical care and rehabilitation.

The objective of this study was to compare physical capacity over time among adults in 3 groups: those without COVID-19 (control group [CG]), those who recovered from COVID without persistent symptoms (short COVID group [SCG]), and those with long COVID (long COVID group [LCG]). A secondary objective was to identify baseline predictors of 6-month HRQoL in the LCG.

This study was a prospective longitudinal cohort study.

In-laboratory assessments were conducted at baseline, 3 months, and 6 months, at either the Center for Interdisciplinary Research in Rehabilitation and Social Integration (Quebec City) or the Orthopedic Clinical Research Unit (Montreal).

A total of 360 age- and sex-matched adults (n = 120 per group), including individuals without a history of COVID-19 (CG), those with short COVID (symptom resolution within 4 weeks, SCG), and those with persistent symptoms ≥12 weeks (LCG) participated in the study.

Participants were categorized based on their COVID-19 history and symptom duration and no intervention or exposure was applied.

Self-reported outcomes measuring HRQoL, comorbidities, sleep quality, pain, and fatigue, along with objective measures such as grip strength, Short Physical Performance Battery (SPPB), 6-min walk test (6MWT), and perceived exertion (Modified Borg Scale) during the 6MWT, were collected. Daily averages for resting heart rate, step count, and minutes of intensive activity were recorded over 7 days using a fitness tracker watch. Generalized estimating equations were used for longitudinal comparisons, and recursive partitioning analysis for predicting HRQoL factors.

Significant time × group interactions were observed for HRQoL, sleep quality, pain, fatigue, SPPB, and 6MWT. Although the LCG showed significant improvements across these outcomes, only the reduction in fatigue reached a clinically meaningful level, whereas the other groups remained stable. A group effect was detected for all outcomes, except for heart rate and minutes of intensive activity, with the LCG consistently showing lower scores across all follow-ups. Recursive partitioning analysis identified 2 baseline predictors of HRQoL at 6 months in the LCG: self-reported fatigue and daily step count.

These findings highlight the persistent impairments in adults with long COVID and emphasize early HRQoL predictor identification to anticipate long-term needs and adjust treatment plans accordingly.