ABSTRACT
BACKGROUND: Although the six-minute-walk test (6MWT) has been used to predict chronic obstructive pulmonary disease (COPD) exacerbations, additional research is necessary to identify more rapid, simpler tests that are directly associated with exacerbations, such as the five-repetition sit-to-stand (5STS) test and 4-m gait speed (4MGS) test. AIMS: To determine the ability of the 5STS and 4MGS tests in predicting severe exacerbations in stable COPD over the following year, and to assess the ability of the best prognostic test to identify patients at high risk of hospital admission correctly. METHODS: This prospective study included 137 patients with stable COPD. Multiple logistic regression models were constructed to assess whether the 6MWT, 5STS, and 4MGS tests were associated with severe exacerbations in the year following the test. Receiver-operating characteristic curves and the area under the curve (AUC) were evaluated to determine the accuracy of each test for identifying patients with severe exacerbations. RESULTS: Scores of <350 m for the 6WMT and ⩽2 for the 5STS test were associated with severe exacerbations in the model adjusted for age and the number of exacerbations in the previous year. The 5STS test and the 6MWT had very similar predictive and discriminative abilities. Odds ratios were 3.20 (95% confidence interval [CI] 1.14-8.96) and 3.84 (95% CI 1.14-12.94) and AUCs were 0.793 (95% CI 0.704-0.882) and 0.783 (95% CI 0.686-0.879), respectively. CONCLUSIONS: The 5STS test predicted the risk of severe exacerbation within the following year among patients with COPD. The 5STS test could replace the 6MWT for identifying patients at high risk of hospital admission.
ABSTRACT
BACKGROUND: Chronic obstructive pulmonary disease (COPD) is a major cause of disability. We aimed to analyse the impact of reduced pulmonary function on non-respiratory impairments and mobility activity limitations in an elderly population with COPD and to elucidate which specific limitations on mobility are related to reduced pulmonary function. METHODS: Cross-sectional study of 110 patients with COPD, recruited from public and university hospital. The effect of impaired pulmonary function on the risk of non-respiratory impairments and mobility limitations was analysed using validated measures, including: the 6-Minute Walk Test (6MWT), skeletal muscle strength, the Short Physical Performance Battery (SPPB), and self-reported mobility questionnaire. Multivariate analysis was used to control for confounders such as age, sex, height, education, and cigarette smoking. RESULTS: Greater impairment of pulmonary function was associated with less distance walked during the 6MWT, poorer SPPB scores, and greater risk of self-reported mobility limitations (p<0.05). Lower forced expiratory volume in 1 s was also associated with a greater risk of limitations in carrying items under 10 pounds (4.54 kg), walking alone up and down a flight of stairs, and walking two or three neighbourhood blocks. There was no clear statistical relationship between pulmonary function impairment and skeletal muscle strength. CONCLUSIONS: Impaired pulmonary function was associated with the 6MWT score and limitations on performance-based and self-reported mobility activities, but not with skeletal muscle strength among elderly COPD patients.
