Is the 1-minute sit-to-stand test a good tool for the evaluation of the impact of pulmonary rehabilitation? Determination of the minimal important difference in COPD

Abstract

BackgroundThe 1-minute sit-to-stand (STS) test could be valuable to assess the level of exercise tolerance in chronic obstructive pulmonary disease (COPD). There is a need to provide the minimal important difference (MID) of this test in pulmonary rehabilitation (PR).MethodsCOPD patients undergoing the 1-minute STS test before PR were included. The test was performed at baseline and the end of PR, as well as the 6-minute walk test, and the quadriceps maximum voluntary contraction (QMVC). Home and community-based programs were conducted as recommended. Responsiveness to PR was determined by the difference in the 1-minute STS test between baseline and the end of PR. The MID was evaluated using distribution and anchor-based methods.ResultsForty-eight COPD patients were included. At baseline, the significant predictors of the number of 1-minute STS repetitions were the 6-minute walk distance (6MWD) (r=0.574; P<10−3), age (r=−0.453; P=0.001), being on long-term oxygen treatment (r=−0.454; P=0.017), and the QMVC (r=0.424; P=0.031). The multivariate analysis explained 75.8% of the variance of 1-minute STS repetitions. The improvement of the 1-minute STS repetitions at the end of PR was 3.8±4.2 (P<10−3). It was mainly correlated with the change in QMVC (r=0.572; P=0.004) and 6MWD (r=0.428; P=0.006). Using the distribution-based analysis, an MID of 1.9 (standard error of measurement method) or 3.1 (standard deviation method) was found. With the 6MWD as anchor, the receiver operating characteristic curve identified the MID for the change in 1-minute STS repetitions at 2.5 (sensibility: 80%, specificity: 60%) with area under curve of 0.716.ConclusionThe 1-minute STS test is simple and sensitive to measure the efficiency of PR. An improvement of at least three repetitions is consistent with physical benefits after PR.

The validation of the sit-to-stand test for COPD patients

“…Confidence in a specific MID usually evolves over time and is confirmed by additional evidence. Interestingly, the study by A. Chambellan and colleagues where the 6MWT was used as an anchor, along with distributional methods, found the same MID estimate as in our study [2].…”

“…A. Chambellan and colleagues noted that the correlation between the post-pulmonary rehabilitation change scores in 1-min STS test and 6-min walk test (6MWT) observed in the STAND-UP study (r= −0.08) was weak in comparison to the correlation coefficient observed in their own study (r=0.50) [2]. They consider whether the discrepancies could be explained by differences in pulmonary rehabilitation programmes or severity of disease in the two populations.…”

Sit-to-stand tests for COPD: A literature review

“…Several studies [10,19,21,22,28,37] have compared the STST with the 6MWT in order to assess its relevance as a tool for evaluation of functional status in COPD patients and healthy subjects. The results obtained by Ozalevli et al in COPD showed a strong correlation between performance in the 1 min-STST and distance walked in the 6-min (r ¼ 0.75, p < 0.001).…”

Prognostic value of simple measures of physical function and muscle strength in COPD: A systematic review

“…In addition, there are normative values [25][26][27] available to guide clinicians' decision on the best treatment options based on the test results. The 1-min STS test [28] is also a good option since it has been shown to be a strong predictor of mortality in patients with COPD [18], has excellent long-term predictive validity [21], is responsive to pulmonary rehabilitation [29], does not require any specific equipment and has normative data available based on age and gender [28]. The disadvantage of the 1-min STS is that it may n/a n/a n/a n/a n/a n/a n/a 5.…”