Confiabilidade do teste da caminhada de seis minutos em pacientes com miastenia gravis generalizada

Abstract

The purpose of this study was to assess the reliability of the six minuteswalking test (6MWT) as a functional capacity test for patients with generalizedmyasthenia gravis (MG). Eleven patients with generalized MG (5 men, six women),aged 55±9 years, were first assessed as to pulmonary function and then submittedto three 6MWT in different days. Heart rate and oxygen saturation were measured(by means of portable oxymeter) during, and dyspnea (by the Borg scale) and distancewalked were measured after, each test. At the three tests distances walked were498 m, 517 m and 520 m (respectively 99%, 103%, and 104% of predicted values).Mean heart rate, oxygen saturation, and dyspnea values showed constant behaviourthrough the three tests. A high relative reliability was found between the tests, withinterclass coefficient correlation over 0.90 (6MWT1-6MWT2, 0.960; 6MWT1-6MWT3, 0.945; and 6MWT2-6MWT3, 0.970); absolute reliability of 4%, 3.5% and4.8%, as well as good repeatability of 11%, 9.8% and 13.4% were found forrespectively the first, second, and third tests. Upper and lower agreement limits, aswell as bias mean values by the Bland-Altman test show clinically acceptability. Itmay hence be said that the 6MWT proved safe, reliable and reproducible, and maybe used for exercise tolerance assessment and follow up of patients with generalizedmyasthenia gravis.