Evaluation of 6-minute walk test (6MWT) in adults with sickle cell disease in São Paulo/SP

• Ano de defesa: 2017
• Autor(a) principal: Norvil, Wesny [UNIFESP]
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Sickle Cell Disease; Hypoxemia; Six-Minute Walking Test; Hemolysis; Doença Falciforme; Hipoxemia; Teste de Caminhada de Seis Minutos; Hemolise
• Link de acesso: https://sucupira.capes.gov.br/sucupira/public/consultas/coleta/trabalhoConclusao/viewTrabalhoConclusao.jsf?popup=true&id_trabalho=5580737; http://repositorio.unifesp.br/handle/11600/50371

Introduction: Sickle-cell Disease (SCD) is the hematological disease, with the most hereditary, monogenic and autosomal features in the world. Its pathophysiology involves hemolysis and vaso-occlusion, which can affect several organs, including the lung. It is observed that hypoxemia in the steady state is a common manifestation in SCD and it has been proven an association with the level of anemia and the degree of hemolysis in previous studies. The 6-minutes-walking test (6MWT) is a simple functional capacity test that evaluates the exercise tolerance according to the distance covered in 6 minutes and with monitoring of the behavior of oxygen saturation and blood pressure. It has been gaining importance in sickle cell disease, since lots of results were found showing the impact of baseline oxygen(O2) desaturation in the 6MWT performance in children with sickle cell disease whereas just a few have been found in adults. Objective: In this current study we aimed at evaluating hypoxemia in sickle-cell adults though the 6MWT and its relation with the clinical-laboratory parameters. Methods: A cross-sectional, analytical and descriptive study was performed in 44 patients with SCD and 19 healthy controls based on the 6MWT and clinical-laboratory data. Results: The group of patients covered a shorter distance [median (interquartile): 416.9m (406.6-444.8)] than controls [652.5m (634.4-665.0); p<0001]. No individual in the control group had baseline or post-test desaturation. Moderate O2 desaturation at rest (defined as SpO2<95%) was observed in 25.0% (n=11) of the patients. The distance walked by the patients showed a positive correlation with hemoglobin (r=0.461, 95% CI: 0.170- 0.678, p=0.002) and negative with reticulocytes count (r=-0.352, 95% CI:-0.601- - 0.041; p=0.023). Patients with moderate desaturation at rest had odds of increase 6.5-fold of post-test desaturation development (OR: 6.5; 95% CI: 1.47-28.71; p=0.021). When evaluating the patients in relation to the absence (G1) or presence (G2) of post-test desaturation (defined as decline O2≥3% from baseline), 14 (31.8%) of the individuals belonging to G2 were observed. Regarding the hemolytic biomarkers, G2 presented a lower HbF level (p=0.041), lower BMI (p=0.007), higher reticulocytes count (p=0.007) and DHL (p=0.002) compared with G1. Conclusion: It was detected a high prevalence of moderate desaturation at steady state as well as post 6MWT in adults with SCD. Desaturation was associated with elevation of hemolysis biomarkers, suggesting being associated with the greater severity of the disease. The detection of these abnormalities in the 6MWT underscores the importance of considering this non-invasive test as a means of monitoring patients with FD, although additional studies are needed to elucidate the role of 6MWT in adults with SCD.