From robustness to frailty: how post-COVID-19 frailty shapes dyspnea, fatigue, and physical and functional status in post-COVID-19 syndrome.

Abstract

To examine the relationship between post-COVID-19 frailty and dyspnea, fatigue, and physical and functional status in subjects with post-COVID-19 syndrome (PCS), and to compare these outcomes according to frailty level. A cross-sectional study was conducted at the University of Granada (March-June 2024). Forty-five previously hospitalized subjects (18-80 years) with PCS were classified as robust (<i>n</i> = 13), pre-frail (<i>n</i> = 21), or frail (<i>n</i> = 11) using the FRAIL scale. Persistent symptoms and physical and functional parameters were assessed using validated questionnaires and standardized tests. Frailty correlated positively with dyspnea at light, moderate, and intense exercise, overall dyspnea, and fatigue, and negatively with physical activity, muscle quality, strength, and performance. Functionality showed a strong association with frailty. Regression analysis identified length of hospital stay and comorbidities as significant factors in the descriptive model, whereas persistent symptoms were not associated. In the physical-functional model, only functionality was associated. Group comparisons revealed a progressive pattern across frailty levels. Post-COVID-19 frailty is associated with greater dyspnea and fatigue, and reduced physical and functional status. Early identification and targeted interventions may be important, although causal inferences are limited by the cross-sectional design, small sample size, and potential overlap between frailty and outcome measures.