Sarah Crook

A multicentre validation of the 1-min sit-to-stand test in patients with COPD.

Our aim was to comprehensively validate the 1-min sit-to-stand (STS) test in chronic obstructive pulmonary disease (COPD) patients and explore the physiological response to the test. We used data from two longitudinal studies of COPD patients who completed inpatient pulmonary rehabilitation programmes. We collected 1-min STS test, 6-min walk test (6MWT), health-related quality of life, dyspnoea and exercise cardiorespiratory data at admission and discharge. We assessed the learning effect, test–retest reliability, construct validity, responsiveness and minimal important difference of the 1-min STS test. In both studies (n=52 and n=203) the 1-min STS test was strongly correlated with the 6MWT at admission (r=0.59 and 0.64, respectively) and discharge (r=0.67 and 0.68, respectively). Intraclass correlation coefficients (95% CI) between 1-min STS tests were 0.93 (0.83–0.97) for learning effect and 0.99 (0.97–1.00) for reliability. Standardised response means (95% CI) were 0.87 (0.58–1.16) and 0.91 (0.78–1.07). The estimated minimal important difference was three repetitions. End-exercise oxygen consumption, carbon dioxide output, ventilation, breathing frequency and heart rate were similar in the 1-min STS test and 6MWT. The 1-min STS test is a reliable, valid and responsive test for measuring functional exercise capacity in COPD patients and elicited a physiological response comparable to that of the 6MWT. The 1-min STS test is a reliable, valid and responsive exercise capacity test in COPD with an MID of 3 repetitions http://ow.ly/teNx307ni0Q

Minimum important difference of the Epworth Sleepiness Scale in obstructive sleep apnoea: estimation from three randomised controlled trials

Background The Epworth Sleepiness Scale (ESS) is a widely used tool for assessing sleepiness in patients with obstructive sleep apnoea (OSA). We aimed to estimate the minimal important difference (MID) in patients with OSA. Methods We used individual data from three randomised controlled trials (RCTs) in patients with OSA where the preintervention to postintervention change in ESS was used as a primary outcome. We used anchor-based linear regression and responder analysis approaches to estimate the MID. For anchors, we used the change in domains of the Functional Outcomes of Sleep Questionnaire and 36-Item Short Form Health Survey. We also used the distribution-based approaches Cohen’s effect size, SE of measurement and empirical rule effect size to support the anchor-based estimates. The final MID was determined by triangulating all estimates to a single MID. Findings A total of 639 patients with OSA were included in our analyses across the three RCTs with a median (IQR) baseline ESS score of 10 (6–13). The median (IQR) ESS change score overall was −2 (−5 to 1). The anchor-based estimates of the MID were between −1.74 and −4.21 points and estimates from the responder analysis were between −1 and −3 points. Distribution-based estimates were smaller, ranging from −1.46 to −2.36. Interpretation We propose an MID for the ESS of 2 points in patients with OSA with a disease severity from mild to severe. This estimate provides the means to plan trials and interpret the clinical relevance of changes in ESS. Trial registration number Provent, NCT01332175; autoCPAP trial, NCT00280800; MOSAIC,ISRCTN (3416388).

The association between daily exacerbation symptoms and physical activity in patients with chronic obstructive pulmonary disease

Background Evidence from longitudinal studies on the impact of exacerbation symptoms on physical activity in chronic obstructive pulmonary disease (COPD) is lacking. The aim of this first exploratory study was to assess the association between exacerbation symptoms and physical activity, and to quantify the relative influence of specific symptoms. Methods We recruited COPD patients at high risk for exacerbations from 2 pulmonary rehabilitation clinics and 1 acute care clinic in Switzerland. For 3 months after discharge, patients completed a daily symptom diary on a smartphone application, the EXAcerbations of Chronic pulmonary disease Tool (EXACT), and wore a pedometer to measure daily steps. We used mixed-effects models to determine the association of daily steps with exacerbation symptoms. Results A total of 21 patients (Global Initiative for Chronic Obstructive Lung Disease grades 2–4) were enrolled for a mean of 94.4 days (standard deviation 4.2). The baseline median number of daily steps was 3,264.6 (interquartile range [IQR]: 1,851.3–4,784.1) and EXACT score was 37.0 (IQR: 30.9–41.4). A 12-point increase in EXACT score (indicating the start of an exacerbation) was statistically significantly associated with a decrease in daily steps of 653.3 (95% CI 969.7–336.9). Chest symptoms (tightness, discomfort and congestion) were more strongly associated with change in steps than breathlessness, and cough and sputum (z-value −4.5 vs −2.9 and −3.0). Conclusion This is the first study to show that, in a small cohort of COPD patients, increases in exacerbation symptoms were associated with a statistically and clinically significant reduction in daily physical activity. These results underscore the importance for symptom control and exacerbation prevention in COPD patients.

Prediction of long-term clinical outcomes using simple functional exercise performance tests in patients with COPD: a 5-year prospective cohort study

The 1-min sit-to-stand (1-min STS) test and handgrip strength test have been proposed as simple tests of functional exercise performance in chronic obstructive pulmonary disease (COPD) patients. We assessed the long-term (5-year) predictive performance of the 1-min sit-to-stand and handgrip strength tests for mortality, health-related quality of life (HRQoL) and exacerbations in COPD patients. In 409 primary care patients, we found the 1-min STS test to be strongly associated with long-term mortality (hazard ratio per 3 more repetitions: 0.81, 95% CI 0.65 to 0.86) and moderately associated with long-term HRQoL. Neither test was associated with exacerbations. Our results suggest that the 1-min STS test may be useful for assessing the health status and long-term prognosis of COPD patients. This study was registered at http://www.clinicaltrials.gov/ (NCT00706602, 25 June 2008).

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

We thank A. Chambellan and colleagues for their interest in our study on the validation of the 1-min sit-to-stand (STS) test in chronic obstructive pulmonary disease (COPD) patients published in the European Respiratory Journal [1]. The authors highlighted some discrepancies between our study results and the results that they found in a similar study of COPD patients, raised questions over the possible cause of this difference and discuss results from their own study that they believe may provide additional information on the responsiveness of the 1-min STS test. Although evaluated in 3 different PR settings, the 1-min STS test shows consistent cross-sectional validity and MID http://ow.ly/kJ0v30equOIThe change in the sit-to-stand test after a pulmonary rehabilitation is not influenced by the initial value http://ow.ly/i2CI30eqprD