Minimal Clinically Important Differences in Inspiratory Muscle Function Variables after a Respiratory Muscle Training Programme in Individuals with Long-Term Post-COVID-19 Symptoms.

OBJECTIVE: To establish the minimal clinically important difference (MCID) for inspiratory muscle strength (MIP) and endurance (IME) in individuals with long-term post-COVID-19 symptoms, as well as to ascertain which of the variables has a greater discriminatory capacity and to compare changes between individuals classified by the MCID. DESIGN: Secondary analysis of randomised controlled trial of data from 42 individuals who performed an 8-week intervention of respiratory muscle training programme. RESULTS: A change of at least 18 cmH2O and 22.1% of that predicted for MIP and 328.5s for IME represented the MCID. All variables showed acceptable discrimination between individuals who classified as "improved" and those classified as "stable/not improved" (area under the curve ≥0.73). MIP was the variable with the best discriminative ability when expressed as a percentage of prediction (Youden index, 0.67; sensitivity, 76.9%; specificity, 89.7%). Participants classified as "improved" had significantly greater improvements in quality of life and lung function compared with the participants classified as "stable/not improved". CONCLUSION: In individuals with long-term post-COVID-19 symptoms, the inspiratory muscle function variables had an acceptable discriminative ability to assess the efficacy of a respiratory muscle training programme. MIP was the variable with the best discriminative ability, showing better overall performance when expressed as a percentage of prediction.

Home-based respiratory muscle training on quality of life and exercise tolerance in long-term post-COVID-19: Randomized controlled trial.

OBJECTIVE: To evaluate the effects of a home-based respiratory muscle training programme (inspiratory [IMT] or inspiratory/expiratory muscles [RMT]) supervised by telerehabilitation on quality of life and exercise tolerance in individuals with long-term post-COVID-19 symptoms. The secondary objective was to evaluate the effects of these programmes on respiratory muscle function, physical and lung function, and psychological state. METHODS: 88 individuals with long-term symptoms of fatigue and dyspnoea after COVID-19 diagnosis were randomly (1:1 ratio) assigned to IMT, IMTsham, RMT or RMTsham groups for an 8-week intervention (40min/day, 6 times/week). Primary outcomes were quality of life (EuroQol-5D questionnaire) and exercise tolerance (Ruffier test). Secondary outcomes were respiratory muscle function (inspiratory/expiratory muscle strength; inspiratory muscle endurance), physical function (lower and upper limb strength [1-min Sit-to-Stand and handgrip force]), lung function (forced spirometry), and psychological status (anxiety/depression levels and post-traumatic stress disorder). All outcomes were measured pre-, intermediate- (4th week), and post-intervention. RESULTS: At post-intervention, there was a statistically significant and large (d>0.90) improvement in quality of life, but not in exercise tolerance, in the RMT group compared with the RMTsham group. Both of the real training groups produced a statistically significant and large increase in inspiratory muscle strength and endurance (d≥0.80) and in lower limb muscle strength (d≥0.77) compared with the 2 sham groups. Expiratory muscle strength and peak expiratory flow showed a statistically significant and large (d≥0.87) increase in the RMT group compared with the other 3 groups. CONCLUSION: Only an 8-week supervised home-based RMT programme was effective in improving quality of life, but not exercise tolerance, in individuals with long-term post-COVID-19 symptoms. In addition, IMT and RMT programmes were effective in improving respiratory muscle function and lower limb muscle strength, but had no impact on lung function and psychological status.

A tele-health primary care rehabilitation program improves self-perceived exertion in COVID-19 survivors experiencing Post-COVID fatigue and dyspnea: A quasi-experimental study.

BACKGROUND: Current evidence suggests that up to 70% of COVID-19 survivors develop post-COVID symptoms during the following months after infection. Fatigue and dyspnea seem to be the most prevalent post-COVID symptoms. OBJECTIVE: To analyze whether a tele-rehabilitation exercise program is able to improve self-perceived physical exertion in patients with post-COVID fatigue and dyspnea. METHODS: Sixty-eight COVID-19 survivors exhibiting post-COVID fatigue and dyspnea derived to four Primary Health Care centers located in Madrid were enrolled in this quasi-experimental study. A tele-rehabilitation program based on patient education, physical activity, airway clearing, and breathing exercise interventions was structured on eighteen sessions (3 sessions/week). Self-perceived physical exertion during daily living activities, dyspnea severity, health-related quality of life and distance walked and changes in oxygen saturation and heart rate during the 6-Minute walking test were assessed at baseline, after the program and at 1- and 3-months follow-up periods. RESULTS: Daily living activities, dyspnea severity and quality of life improved significantly at all follow-ups (p<0.001). Additionally, a significant increase in oxygen saturation before and after the 6-Minute Walking test was found when compared with baseline (P<0.001). Heart rate adaptations at rest were found during the follow-up periods (P = 0.012). Lower perceived exertion before and after the 6-Minute Walking test were also observed, even if larger distance were walked (P<0.001). CONCLUSION: Tele-rehabilitation programs could be an effective strategy to reduce post-COVID fatigue and dyspnea in COVID-19 survivors. In addition, it could also reduce the economic burden of acute COVID-19, reaching a greater number of patients and releasing Intensive Unit Care beds for prioritized patients with a severe disease. STUDY REGISTRATION: The international OSF Registry registration link is https://doi.org/10.17605/OSF.IO/T8SYB.

Construct validity of the Spanish version of the Post-COVID-19 Functional Status scale and validation of the web-based form in COVID-19 survivors.

OBJECTIVES: To assess the psychometric characteristics of the Spanish Post-COVID-19 Functional Status (PCFS) scale (web-based and paper-based forms) and the test-retest reliability of the web-based form. STUDY DESIGN AND SETTING: Cross-sectional study of 125 COVID-19 survivors. The test-retest reliability of the web-based form was assessed at 7 days after the first evaluation. We collected symptoms, functional status (PCFS scale), health-related quality of life (EuroQol-5D questionnaire, EQ-5D-5L), activities of daily living limitations [Barthel Index and Global Activity Limitation Index, GALI] and psychological state (Hospital Anxiety and Depression Scale, HADS). RESULTS: The paper- and web-based forms of the Spanish PCFS scale showed adequate construct validity, and the web-based form provided substantial test-retest reliability (kappa = 0.63). The percentage of agreement between the web-based and paper-based forms was high (88%). Functional status showed a high correlation with EQ-5D-5L (inverse) and GALI (direct) (both; Rho ≥ .743), a moderate correlation with HADS (Rho ≥ .409) and a low correlation with the Barthel Index (Rho < .30). The Kruskal-Wallis test showed statistically significant differences in EQ-5D-5L, GALI and HADS according to the degree of functional status. CONCLUSION: The Spanish version of the PCFS scale (web-based and paper-based forms) showed adequate construct validity, and the web-based form provided substantial test-retest reliability in COVID-19 survivors.

Longitudinal study of changes observed in quality of life, psychological state cognition and pulmonary and functional capacity after COVID-19 infection: A six- to seven-month prospective cohort.

AIMS: To investigate the health-related quality of life (HRQoL), symptoms, psychological and cognitive state and pulmonary and physical function of nonhospitalised COVID-19 patients at long-term, and to identify factors to predict a poor HRQoL in this follow-up. BACKGROUND: Studies have focused on persistent symptoms of hospitalised COVID-19 patients in the medium term. Thus, long-term studies of nonhospitalised patients are urgently required. DESIGN: A longitudinal cohort study. METHODS: In 102 nonhospitalised COVID-19 patients, we collected symptoms at 3 months (baseline) and at 6-7 months (follow-up) from diagnosis (dyspnoea, fatigue/muscle weakness and chest/joint pain), HRQoL, psychological state, cognitive function, pulmonary and physical function. This study adhered to the STROBE statement. RESULTS: HRQoL was impaired in almost 60% of the sample and remained impaired 6-7 months. At 3 months, more than 60% had impaired physical function (fatigue/muscle weakness and reduced leg and inspiratory muscle strength). About 40%-56% of the sample showed an altered psychological state (post-traumatic stress disorder (PTSD), anxiety/depression), cognitive function impairment and dyspnoea. At 6-7-months, only a slight improvement in dyspnoea and physical and cognitive function was observed, with a very high proportion of the sample (29%-55%) remained impaired. Impaired HRQoL at 6-7 months was predicted with 82.4% accuracy (86.7% sensitivity and 83.3% specificity) by the presence at 3 months of muscle fatigue/muscle weakness (OR = 5.7 (1.8-18.1)), PTSD (OR = 6.0 (1.7-20.7)) and impaired HRQoL (OR = 11.7 (3.7-36.8)). CONCLUSION: A high proportion of nonhospitalised patients with COVID-19 experience an impaired HRQoL, cognitive and psychological function at long-term. HRQoL, PTSD and dyspnoea at 3 months can identify the majority of patients with COVID-19 who will have impaired quality of life at long-term. RELEVANCE TO CLINICAL PRACTICE: Treatments aimed at improving psychological state and reducing the fatigue/muscle weakness of post-COVID-19 patients could be necessary to prevent the patients' HRQoL from being impaired at 6-7 months after their reported recovery.