Distúrbios do sono, capacidade de exercício e nível de atividade física diária em crianças e adolescentes com fibrose cística

Abstract

Introduction: Cystic fibrosis (CF) is an autosomal recessive multisystem genetic disease that primarily affects the epithelium of several organs, although the respiratory disfunction is the leading cause of mortality in this population. The influence of pulmonary function, nutritional status, exacerbations and exercise capacity on the prognosis of CF is well documented in the literature. Studies have shown that sleep disorders are more common in CF than in healthy individuals and may be present before daytime clinical manifestations, regardless of impaired pulmonary function, playing an important role in quality of life and disease progression. Objective: To evaluate the presence of sleep disorder and its correlation with pulmonary function, nutritional status and morbidity markers (length of hospitalization and use of antibiotics), as well as its association on exercise capacity and daily physical activity levels of children and adolescents with CF. Methods: This thesis is divided into two articles. Both studies are cross-sectional and included children and adolescents aged between six and 18 years, with a diagnosis of CF and attended at a reference center located in Vitória, Espírito Santo. Information regarding sociodemographic profile, sleep evaluation, pulmonary function, Shwachman Kulczycki (SK) score and nutritional status were performed. For the elaboration of the first article, data on spirometry, bioimpedance, polysomnography, history of hospitalizations and use of antibiotics in the last year were used. As for the second article, besides the polysomnography sleep evaluation, an exercise capacity test (modified shuttle test - MST) was performed and the daily physical activity levels were evaluated by using both an international physical activity questionnaire for children and adolescents and an accelerometer for five days. The presence of nocturnal hypoxemia was considered when the participant remained more than 5% of the total sleep time (TTS) with oxyhemoglobin saturation (SpO2) below 90% and obstructive sleep apnea syndrome (OSAS) when the obstructive apnea hyponeia index was greater than or equal to 2 per hour. Results: In both studies, 31 patients with a median age of 9.6 years and forced expiratory volume in one second (FEV1) of 68.1±24.4% were included. OSAS was present in 32.3% and nocturnal hypoxemia in 29% of the studied sample. In article 1, individuals with OSAS and nocturnal hypoxemia had lower spirometric values compared to patients without OSAS and without hypoxemia, but the nocturnal hypoxemia group also had lower SK score, longer hospitalization and antibiotic use. The TTS with SpO2<90% was associated with the hospitalization time (r2=0.53). In article 2, the longer the distance achieved in the MST, the higher the average SpO2 during sleep (r=0.40) and the lower the percentage of total sleep time with SpO2<90% (r=-0.49). The lower the SpO2 at the end of the MST, the higher the occurrence of sleep apnea (r=-0.48) and the lower mean nocturnal SpO2 (r=0.45). The levels of daily physical activity correlated with sleep architecture, so that the longer the daily sedentary activity time, the higher the percentage of stage II (r=0.5) and the lower the percentage of REM stage (r=-0.47) sleep. The group with OSAS and the group with nocturnal hypoxemia presented significantly lower values of distance and final SpO2 in the MST (p<0.05) than the group without these disorders. Conclusion: Children and adolescents with CF have presented sleep disorders, including OSAS and nocturnal hypoxemia. Individuals with nocturnal hypoxemia have lower lung function, worse clinical score and higher morbidity, as well as the TTS with SpO2<90% was associated with the higher hospitalization time and exercise intolerance. OSAS correlates with pulmonary function, but there was no association between it and other clinical outcomes. The % of time in sedentary activities during the day correlated with a higher % of time in sleep stage II and shorter % of REM sleep time.