RESUMEN
ABSTRACT Objective: One of the common limitations after COVID-19 pneumonia is the decrease in exercise capacity. The identification of the factors affecting exercise capacity and the assessment of patients at risk are important for determining treatment strategy. This study was conducted to determine the predictors of decreased exercise capacity in long post-COVID-19 patients. Methods: We investigated the association of exercise capacity as measured by the incremental shuttle walk test (ISWT) with age, sex, spirometric variables, respiratory and peripheral muscle strength, quality of life, fatigue, hospital anxiety depression scale, chest X-ray involvement, and hospitalization. The patients were divided into three groups: outpatients, inpatients, and ICU patients. Regression analysis was used to determine which parameters were significant predictors of exercise capacity. Results: Of the 181 patients included in the study, 56 (31%) were female. The mean ISWT in percentage of predicted values (ISWT%pred) was 43.20% in the whole sample, whereas that was 52.89%, 43.71%, and 32.21% in the outpatient, inpatient, and ICU patient groups, respectively. Linear regression analysis showed that predictors of decreased ISWT%pred were sex (b = 8.089; p = 0.002), mMRC scale score (b = −7.004; p ≤ 0.001), FVC%pred (b = 0.151; p = 0.003), and handgrip strength (b = 0.261; p = 0.030). Conclusions: In long post-COVID-19 patients, sex, perception of dyspnea, restrictive pattern in respiratory function, and decrease in peripheral muscle strength are predictors of reduced exercise capacity that persists three months after COVID-19. In this context, we suggest that pulmonary rehabilitation might be an important therapy for patients after COVID-19.
RESUMO Objetivo: Uma das limitações comuns após a pneumonia por COVID-19 é a diminuição da capacidade de exercício. A identificação dos fatores que afetam a capacidade de exercício e a avaliação dos pacientes em risco são importantes para determinar a estratégia de tratamento. Este estudo foi conduzido para determinar os preditores de diminuição da capacidade de exercício em pacientes pós-COVID-19 longa. Métodos: Foi investigada a associação da capacidade de exercício medida pelo incremental shuttle walk test (ISWT, teste de caminhada incremental) com idade, sexo, variáveis espirométricas, força muscular respiratória e periférica, qualidade de vida, fadiga, escala hospitalar de ansiedade e depressão, envolvimento na radiografia de tórax e status de atendimento. Os pacientes foram divididos em três grupos: pacientes ambulatoriais, pacientes internados e pacientes em UTI. A análise de regressão foi utilizada para determinar quais parâmetros eram preditores significativos da capacidade de exercício. Resultados: Dos 181 pacientes incluídos no estudo, 56 (31%) eram do sexo feminino. O ISWT médio em porcentagem dos valores previstos (ISWT%prev) foi de 43,20% em toda a amostra, enquanto foi de 52,89%, 43,71% e 32,21% nos grupos de pacientes ambulatoriais, internados e em UTI, respectivamente. A análise de regressão linear mostrou que os preditores de diminuição do ISWT%prev foram sexo (b = 8,089; p = 0,002), pontuação na escala mMRC (b = −7,004; p ≤ 0,001), CVF%prev (b = 0,151; p = 0,003), e força de preensão manual (b = 0,261; p = 0,030). Conclusões: Em pacientes pós-COVID-19 longa, sexo, percepção de dispneia, padrão restritivo da função respiratória e diminuição da força muscular periférica são preditores de redução da capacidade de exercício que persiste três meses após COVID-19. Nesse contexto, sugerimos que a reabilitação pulmonar pode ser uma terapia importante para pacientes pós-COVID-19.
RESUMEN
SUMMARY OBJECTIVE: This study aimed to investigate if there is any correlation between the quantitative computed tomography and the impulse oscillometry or spirometry results of post-COVID-19 patients. METHODS: The study comprised 47 post-COVID-19 patients who had spirometry, impulse oscillometry, and high-resolution computed tomography examinations at the same time. The study group consisted of 33 patients with quantitative computed tomography involvement, while the control group included 14 patients who did not have CT findings. The quantitative computed tomography technology was used to calculate percentages of density range volumes. The relationship between percentages of density range volumes for different quantitative computed tomography density ranges and impulse oscillometry-spirometry findings was statistically analyzed. RESULTS: In quantitative computed tomography, the percentage of relatively high-density lung parenchyma, including fibrotic areas, was 1.76±0.43 and 5.65±3.73 in the control and study groups, respectively. The percentages of primarily ground-glass parenchyma areas were found to be 7.60±2.86 and 29.25±16.50 in the control and study groups, respectively. In the correlation analysis, the forced vital capacity% predicted in the study group was correlated with DRV%[(-750)-(-500)] (volume of the lung parenchyma that has density between (-750)-(-500) Hounsfield units), but no correlation with DRV%[(-500)-0] was detected. Also, reactance area and resonant frequency were correlated with DRV%[(-750)-(-500)], while X5 was correlated with both DRV%[(-500)-0] and DRV%[(-750)-(-500)] density. Modified Medical Research Council score was correlated with predicted percentages of forced vital capacity and X5. CONCLUSION: After COVID-19, forced vital capacity, reactance area, resonant frequency, and X5 correlated with the percentages of density range volumes of ground-glass opacity areas in the quantitative computed tomography. X5 was the only parameter correlated with density ranges consistent with both ground-glass opacity and fibrosis. Furthermore, the percentages of forced vital capacity and X5 were shown to be associated with the perception of dyspnea.