title: Sit-to-stand test and 6-min walking test correlation in patients with chronic obstructive pulmonary disease.
abstract: BACKGROUND
  The 6-min walking test (6MWT) is one of the most commonly used tests to assess exercise capacity during chronic obstructive pulmonary disease (COPD). However, it is a relatively time-consuming test. Many authors assessed the usefulness of simpler methods, as the sit-to-stand test (STST), to estimate exercise capacity.
  
  
  OBJECTIVE
  To demonstrate the feasibility of STST, in comparison to 6MWT, for the evaluation of functional status in Tunisian COPD patients and evaluate its correlation to the severity of the disease.
  
  
  METHODS
  We studied patients with COPD (Global Initiative for Chronic Obstructive Lung Disease A-D). All patients had plethysmography and manual quadriceps femoris muscle strength evaluation. Each patient completed a 6MWT and a STST. During the tests, dyspnea severity (Borg scale), heart rate, pulsed oxygen saturation, and blood pressure were measured.
  
  
  RESULTS
  In 49 patients with stable COPD (mean age 67.06 ± 8.4 years, mean forced expiratory volume in the first second 46.25% ± 19.64%), 6MWT and STST were correlated with each other (r = 0.47, P = 0.001). During 6MWT and STST, the rise in heart rate, systolic blood pressure, and severity of dyspnea were statistically significant compared to baseline (P < 0.05). However, cardiorespiratory stress was lower after STST than after 6MWT (P < 0.05). A statistically significant positive correlation was noted between the 6MWT distance and forced vital capacity (r = 0.357, P < 0.05). The 6MWT was negatively correlated with dyspnea severity at baseline (r = -0.289, P < 0.05) and with BODE index (r = -0.672, P < 0.01). STST was correlated only with age (r = 0.377, P < 0.01). No correlation was found between both tests and quadriceps femoris strength.
  
  
  CONCLUSIONS
  As like as 6MWT, STST can determine functional status during COPD. In addition, it is less time consuming and produces less hemodynamical stress compared to 6MWT. STST can be used as an alternative for 6MWT in patients with COPD.
authors.affiliation: Department of Respiratory, Research Unit 12SP06, Tunis El Manar University, Faculty of Medicine of Tunis, Rabta Hospital, Tunisia.
authors.forename: Mjid
authors.initials: M
authors.lastname: Meriem
authors.affiliation: Department of Respiratory, Research Unit 12SP06, Tunis El Manar University, Faculty of Medicine of Tunis, Rabta Hospital, Tunisia.
authors.forename: Jouda
authors.initials: J
authors.lastname: Cherif
authors.affiliation: Department of Respiratory, Research Unit 12SP06, Tunis El Manar University, Faculty of Medicine of Tunis, Rabta Hospital, Tunisia.
authors.forename: Sonia
authors.initials: S
authors.lastname: Toujani
authors.affiliation: Department of Respiratory, Research Unit 12SP06, Tunis El Manar University, Faculty of Medicine of Tunis, Rabta Hospital, Tunisia.
authors.forename: Yassine
authors.initials: Y
authors.lastname: Ouahchi
authors.affiliation: Department of Preventive Medicine, Tunis El Manar University, Faculty of Medicine of Tunis, 1007 Tunis, Tunisia.
authors.forename: Abdelmajid Ben
authors.initials: AB
authors.lastname: Hmida
authors.affiliation: Department of Respiratory, Research Unit 12SP06, Tunis El Manar University, Faculty of Medicine of Tunis, Rabta Hospital, Tunisia.
authors.forename: Majed
authors.initials: M
authors.lastname: Beji
keywords: Chronic obstructive pulmonary disease; functional status; muscle dysfunction; pulmonary function; survival