title: Six-minute walk test and respiratory muscle strength in patients with uncontrolled severe asthma: a pilot study.
abstract: OBJECTIVE
  To evaluate respiratory muscle strength and six-minute walk test (6MWT) variables in patients with uncontrolled severe asthma (UCSA).
  
  
  METHODS
  This was a cross-sectional study involving UCSA patients followed at a university hospital. The patients underwent 6MWT, spirometry, and measurements of respiratory muscle strength, as well as completing the Asthma Control Test (ACT). The Mann-Whitney test was used in order to analyze 6MWT variables, whereas the Kruskal-Wallis test was used to determine whether there was an association between the use of oral corticosteroids and respiratory muscle strength.
  
  
  RESULTS
  We included 25 patients. Mean FEV1 was 58.8 ± 21.8% of predicted, and mean ACT score was 14.0 ± 3.9 points. No significant difference was found between the median six-minute walk distance recorded for the UCSA patients and that predicted for healthy Brazilians (512 m and 534 m, respectively; p = 0.14). During the 6MWT, there was no significant drop in SpO2. Mean MIP and MEP were normal (72.9 ± 15.2% and 67.6 ± 22.2%, respectively). Comparing the patients treated with at least four courses of oral corticosteroids per year and those treated with three or fewer, we found no significant differences in MIP (p = 0.15) or MEP (p = 0.45).
  
  
  CONCLUSIONS
  Our findings suggest that UCSA patients are similar to normal subjects in terms of 6MWT variables and respiratory muscle strength. The use of oral corticosteroids has no apparent impact on respiratory muscle strength.
authors.affiliation: Hospital das Clínicas, Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Luiz Fernando Ferreira
authors.initials: LF
authors.lastname: Pereira
authors.affiliation: School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Eliane Viana
authors.initials: EV
authors.lastname: Mancuzo
authors.affiliation: Hospital das Clínicas, Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Camila Farnese
authors.initials: CF
authors.lastname: Rezende
authors.affiliation: School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Ricardo de Amorim
authors.initials: Rde A
authors.lastname: Côrrea
mesh_terms: D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D001249:Asthma / Q000188:drug therapy / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005080:Exercise Test / Q000379:methods*; D017079:Exercise Tolerance / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000187:drug effects / Q000502:physiology*; D010865:Pilot Projects; D011965:Receptors, Glucocorticoid / Q000627:therapeutic use; D012720:Severity of Illness Index; D013147:Spirometry; D013997:Time Factors; D016138:Walking / Q000502:physiology*
chemical_list: D000305:Adrenal Cortex Hormones; D011965:Receptors, Glucocorticoid