Chest
Spirometry and Dyspnea in Patients With COPD: When Small Differences Mean Little
Section snippets
Setting
We recruited individuals with severe COPD who were participating in a supervised respiratory rehabilitation program. Participants admitted to the rehabilitation program came from the community, were receiving maximal medical therapy, and had no other active medical conditions (including congestive heart failure, significant anemia, or substantial obesity).5 Most individuals in the rehabihtation program had been referred because of reduced exercise tolerance, inability to perform activities of
RESULTS
We recruited 112 patients in groups of between 5 and 13 individuals (15 groups). The typical participant was 67 years old with symptomatic COPD for 10 years. Half were men and half were women. The distributions of age, gender, and spirometry were similar to the general characteristics of patients enrolled in the respiratory rehabilitation program.7 Patients varied in their severity of disease, with FEV1 values ranging from 12% predicted to 86% predicted. The mean FEV1 was 35% predicted (SD=16),
DISCUSSION
Dyspnea in patients with chronic lung disease is a complex subjective phenomenon accompanied by complex neurophysiology.8 In this study, we estimated the threshold at which a difference in FEV1 tended to be associated with a small but noticeable difference in breathing for the average patient with severe COPD. By comparing objective differences in FEV1 to subjective comparison ratings of breathing ability, we found that the threshold for the FEV1 was about 112 mL for patients who had an average
REFERENCES (26)
- et al.
Can there be a more patient centered approach to determining clinically important effect sizes for randomized treatment trials
J Clin Epidemiol
(1994) - et al.
Randomised controlled trial of respiratory rehabilitation
Lancet
(1994) - et al.
Breathlessness in patients with severe chronic airflow limitation: physiologic correlates
Chest
(1992) Pulmonary-function testing
N Engl J Med
(1990)- et al.
Evaluation of clinical methods for rating dyspnea
Chest
(1993) - et al.
The natural history of chronic airflow obstruction
BMJ
(1977) - et al.
Long-term outcome after respiratory rehabilitation
Can Med Assoc J
(1987) Standardization of spirometry, 1994 update
Am J Respir Crit Care Med
(1995)- et al.
Exertional breathlessness in patients with chronic airflow limitation: the role of lung hyperinflation
Am Rev Respir Dis
(1993) Lung function testing: selection of reference values and interpretative strategies
Am Rev Respir Dis
(1991)
Assessing the clinical importance of symptomatic improvements: an illustration in rheumatology
Arch Intern Med
Minimum important difference between patients with rheumatoid arthritis: the patient's perspective
J Rheumatol
Cited by (99)
Effects of the tai chi qigong programme on functional capacity, and lung function in chronic obstructive pulmonary disease patients: A ramdomised controlled trial
2020, Journal of Traditional and Complementary MedicineShould continuous rather than single-injection interscalene block be routinely offered for major shoulder surgery? A meta-analysis of the analgesic and side-effects profiles
2018, British Journal of AnaesthesiaCitation Excerpt :Importantly, we found no evidence for CISB-related complications or catheter-related technical issues in this systematic review. While CISB was associated with a small impairment in physiological indices of respiratory function that seemed to be well-tolerated by healthy study participants (very low evidence),68 this may be clinically relevant in high-risk subjects.69,70 The effects of CISB on motor function could not be ascertained because of the variability in outcome measures in a small number of trials.
Quality and reproducibility of spirometry in COPD patients in a randomized trial (UPLIFT<sup>®</sup>)
2013, Respiratory MedicineCitation Excerpt :Although Herpel et al. suggested that FEV1 changes >0.225 L likely represent true changes in lung function,7 we demonstrated that changes greater than 0.280–0.320 L would be required to exceed the normal between-test variation. However, FEV1 changes over time are biased by training in spirometry and patient characteristics, while changes within the normal variation may still represent a clinically meaningful result when accompanied by symptom changes.16 Therefore, some experts have suggested that the minimal clinically important difference between two measurements is best estimated by the standard error, which would be around 0.180 L for UPLIFT®.6,17
FEV<inf>1</inf>minimum important difference versus minimal detectable difference? In search of the unicorn
2021, American Journal of Respiratory and Critical Care Medicine
This project was funded through an Ontario Career Scientist award (Dr. Redelmeier), an Ontario Ministry of Health Research Personnel Development Fellowship award (Dr. Min), and grants from the Ontario Thoracic Society, the National Cancer Institute of Canada, and the West Park Hospital Foundation (Dr. Redelmeier).