Six-Minute Walk Test Results Predict Risk of Hospitalization for Youths with Cystic Fibrosis: A 5-Year Follow-Up Study
Donadio MCAV, Heinzmann-Filho JP, Vendrusculo FM, Frasson PX, Marostica PJ. Six-Minute Walk Test Results Predict Risk of Hospitalization for Youths with Cystic Fibrosis: A 5-Year Follow-Up Study. The Journal of Pediatrics. 2017;182. doi:10.1016/j.jpeds.2016.11.071.
The purpose of this study was to determine if the 6 minute walk test, along with multiple other variables, could predict the risk of hospitalization for pulmonary exacerbation in children and adolescents with cystic fibrosis over a five year period. The other variables include anthropometry, chronic pseudomonas aeroginosa colonization, pulmonary function, and respiratory muscle strength. The evaluated values for lung function were forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and forced expiratory flow 25% and 75% of FVC (FEF25%-75%) Of the 41 participants that were eligible for the study, only 26 participants met the inclusion criteria of being able to perform all of the required tests (satisfactory lung function, respiratory muscle strength, and the 6MWT) and being able to attend the annual appointments. The participants were between 6-18 years old who all had a confirmed clinical diagnosis of cystic fibrosis. In regards to the 6MWT, the patients were instructed to walk down a 30 m corridor as fast as possible for 6 minutes. HR, oxygen saturation, blood pressure, respiratory rate, and the modified BORG scale were all recorded. Each patient was seen once a year to perform the necessary tests.
The results indicate that participants who had a greater 6MWT had a reduced risk for hospitalization due to pulmonary exacerbation. Specifically, participants who ambulated <577.5 meters had 4 times the risk of being hospitalized. In fact the 6MWT was the only independent variable associated with the lowest risk for the first hospitalization This study also found that if a participant was hospitalized, a decreased amount of total days spent in the hospital was seen with greater 6MWT scores. There was a moderate positive correlation between FEV1 and the 6MWT however there was no significant association for MIP and MEP. This study had many strengths, including the fact that the participants were followed over a long period of time (5 years) and the age range of the participants was so varied at 6-18 years old. This study also had some limitations. For example, the same size was low at 26 participants. Also there was not much differentiation on what type of CF each patient had and how much it had progressed. There were no interventions performed specifically through this study, as it was done to determine if the 6MWT could be a good predictive outcome measure. The article mentioned how the patients continued their normal physical therapy schedule, but there were no details on what that consisted of. In conclusion, this study determined that the 6MWT is a good predictive indicator for risk of hospitalization for children and adolescents with cystic fibrosis.