Objective: To determine the accuracy of the variables related to the fixed-height stair climbing test (SCT) using maximal oxygen uptake (VO2 max) as the gold standard.
Methods: The SCT was performed on a staircase consisting of 6 flights (72 steps; 12.16 m total height), with verbal encouragement, in 51 patients. Stair-climbing 'time' was measured, and the variables 'work' and 'power' also being calculated. The VO2 max was measured using ergospirometry according to the Balke protocol. We calculated the Pearson linear correlation (r), as well as the values of p, between the SCT variables and VO2 max. To determine accuracy, the VO2 max cut-off point was set at 25 mL/kg/min, and individuals were classified as normal or altered. The cut-off points for the SCT variables were determined using the receiver operating characteristic curve. The Kappa statistic (k) was used in order to assess concordance.
Results: The following values were obtained for the variable 'time': cut-off point = 40 s; x= 41 +/= 15.5 s; r = "0.707; p < 0.005; specificity = 89%; sensibility = 83%; accuracy = 86%; and k = 0.724. For 'power', the values obtained were as follows: cut-off point = 200 w; x= 222.3 +/= 95.2 w; r = 0.515; p < 0.005; specificity = 67%; sensibility = 75%; accuracy = 71%; and k = 0.414. Since the correlation between 'work' and VO2 max was not significant, that variable was discarded.
Conclusion: Of the SCT variables tested, using VO2 max as the gold standard, the variable 'time' was the most accurate.