Longitudinal Analysis of Respiratory Muscle Strength Recovery in Post-COVID-19 Patients: A Comparative Study of Acute and Long-Term Outcomes in Moderate to Severe Cases

<bold>Purpose:</bold> This study aimed to evaluate the acute (up to 3 months) and long-term (after 12 months) prevalence of respiratory muscle strength (RMS) weakness and reduction in post-COVID-19 patients who experienced moderate to severe forms of the disease. <bold>Methods:</bold> We assessed RMS in a cohort of 26 patients with an average age of 55±11 years, predominantly female, who had recovered from moderate to severe COVID-19. RMS was measured at two intervals: within three months and twelve months post-infection. RMS weakness was classified according to Rodrigues et., (2019) and RMS reduction according to Pessoa et al. (2019) reference values. <bold>Results:</bold> Initially, in the baseline, the prevalence of RMS weakness was observed in 6 (23%) patients, while RMS reduction was noted in 12 (46%) patients. Long-term follow-up, 12 months after baseline, revealed a significant decrease in the prevalence of RMS weakness to 1 (3.8%) and reduction to 5 (19.2%), indicating an improvement in RMS from an average of 73.6±27.2 to 82.8±8.3 cmH2O (p=0.16). Notably, the RMS reduction prevalence was markedly higher in patients with severe disease compared to those with moderate symptoms (88±27 vs 75±32% of predicted, p=0.05). Furthermore, a greater average increase in RMS in patients with severe disease (Δ12±9 vs Δ6±1 cmH2O, p=0.05) was observed, underscoring the differential impact of disease severity on recovery trajectories. <bold>Conclusion:</bold> Our findings highlight a significant initial prevalence of RMS weakness and reduction in individuals recovering from moderate to severe COVID-19. The observed improvements suggest potential recovery of RMS over time.