TY - JOUR
T1 - Optimizing the 6-min walk test as a measure of exercise capacity in COPD
AU - Chandra, Divay
AU - Wise, Robert A.
AU - Kulkarni, Hrishikesh S.
AU - Benzo, Roberto P.
AU - Criner, Gerard
AU - Make, Barry
AU - Slivka, William A.
AU - Ries, Andrew L.
AU - Reilly, John J.
AU - Martinez, Fernando J.
AU - Sciurba, Frank C.
N1 - Funding Information:
Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts of interest: Dr Make has participated in advisory boards, speaker bureaus, consultations, and multicenter clinical trials with funding from the National Heart, Lung, and Blood Institute; Abbott Laboratories; Astellas Pharma US, Inc; AstraZeneca; Boehringer Ingelheim GmbH; Dey Pharma LP; Forest Laboratories, Inc; GlaxoSmithKline plc; Merck & Co, Inc; MedImmune, LLC; Nabi Biopharmaceuticals; Novartis Pharmaceuticals Corporation; Takeda Pharmaceuticals International GmbH; Pfizer, Inc; Philips Respironics; Sunovion Pharmaceuticals Inc; Sequel Pharmaceuticals, Inc; and Talecris Biotherapeutics. Dr Martinez has participated in advisory boards in COPD development for Actelion Pharmaceuticals Ltd; AstraZeneca; Bayer AG; BoomComm; Fb Communications; Forest Laboratories, Inc; Almirall, SA; GlaxoSmithKline plc; Ikaria, Inc; MedImmune LLC; Merck & Co, Inc; Novartis Pharmaceuticals Corporation; Takeda Pharmaceuticals International GmbH; Pearl Therapeutics Inc; Pfizer, Inc; Hoffmann-La Roche Inc; Bayer Schering Pharma AG; and Talecris Biotherapeutics. He has been a member of steering committees for COPD studies sponsored by Actelion Pharmaceuticals, Inc; GlaxoSmithKline plc; Forest Laboratories, Inc; Mpex Pharmaceuticals, Inc; and Takeda Pharmaceuticals International GmbH. He has participated in Food and Drug Administration mock panels for Boehringer Ingelheim GmbH and Forest Laboratories, Inc. The University of Michigan received funds from Boehringer Ingelheim GmbH for a COPD study. Dr Martinez has served on speaker's bureaus or in continuing medical education activities sponsored by the American Lung Association; Almirall, SA; Altana; AstraZeneca; Boehringer Ingelheim GmbH; CME Incite; ePocrates, Inc; Forest Laboratories, Inc; The France Foundation; GlaxoSmithKline plc; Med Ed, Inc; NACE International; Pfizer, Inc; Potomac Center for Medical Education; Prescott Pharmaceuticals; Sanofi-Aventis US LLC; Vox Medica, Inc; WebMD, LLC; and UpToDate, Inc. He has received royalties from Associates in Medical Marketing and Castle Connolly Medical Ltd. Dr Sciurba has received research funds from the National Institutes of Health; GlaxoSmithKline plc; Pfizer, Inc; Boehringer Ingelheim GmbH; and Forest Laboratories, Inc. He has received consulting funds from GlaxoSmithKline plc; AstraZeneca plc; and PnuemRX. Drs Chandra, Wise, Kulkarni, Benzo, Criner, Ries, and Reilly and Mr Slivka have reported that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
Funding Information:
Funding/Support: The National Emphysema Treatment Trial (NETT) is supported by contracts with the National Heart, Lung, and Blood Institute [N01HR76101 through N01HR76119, P50HL084948]; the Centers for Medicare & Medicaid Services; and the Agency for Healthcare Research and Quality. This article is subject to the National Institutes of Health public access policy ( http://www.nhlbi.nih.gov/funding/policies/public-access.htm ).
PY - 2012/12
Y1 - 2012/12
N2 - Background: It is uncertain whether the effort and expense of performing a second walk for the 6-min walk test improves test performance. Hence, we attempted to quantify the improvement in 6-min walk distance if an additional walk were to be performed. Methods: We studied patients consecutively enrolled into the National Emphysema Treatment Trial who prior to randomization and after 6 to 10 weeks of pulmonary rehabilitation performed two 6-min walks on consecutive days (N = 396). Patients also performed two 6-min walks at 6-month follow-up after randomization to lung volume reduction surgery (n = 74) or optimal medical therapy (n = 64). We compared change in the first walk distance to change in the second, average-of-two, and best-of-two walk distances. Results: Compared with the change in the first walk distance, change in the average-of-two and best-of-two walk distances had better validity and precision. Specifically, 6 months after randomization to lung volume reduction surgery, changes in the average-of-two(r = 0.66 vs r = 0.58, P = .01) and best-of-two walk distances (r = 0.67 vs r = 0.58, P = .04) better correlated with the change in maximal exercise capacity (ie, better validity). Additionally, the variance of change was 14% to 25% less for the average-of-two walk distances and 14% to 33% less for the best-of-two walk distances than the variance of change in the single walk distance, indicating better precision. Conclusions: Adding a second walk to the 6-min walk test significantly improves its performance in measuring response to a therapeutic intervention, improves the validity of COPD clinical trials, and would result in a 14% to 33% reduction in sample size requirements. Hence, it should be strongly considered by clinicians and researchers as an outcome measure for therapeutic interventions in patients with COPD.
AB - Background: It is uncertain whether the effort and expense of performing a second walk for the 6-min walk test improves test performance. Hence, we attempted to quantify the improvement in 6-min walk distance if an additional walk were to be performed. Methods: We studied patients consecutively enrolled into the National Emphysema Treatment Trial who prior to randomization and after 6 to 10 weeks of pulmonary rehabilitation performed two 6-min walks on consecutive days (N = 396). Patients also performed two 6-min walks at 6-month follow-up after randomization to lung volume reduction surgery (n = 74) or optimal medical therapy (n = 64). We compared change in the first walk distance to change in the second, average-of-two, and best-of-two walk distances. Results: Compared with the change in the first walk distance, change in the average-of-two and best-of-two walk distances had better validity and precision. Specifically, 6 months after randomization to lung volume reduction surgery, changes in the average-of-two(r = 0.66 vs r = 0.58, P = .01) and best-of-two walk distances (r = 0.67 vs r = 0.58, P = .04) better correlated with the change in maximal exercise capacity (ie, better validity). Additionally, the variance of change was 14% to 25% less for the average-of-two walk distances and 14% to 33% less for the best-of-two walk distances than the variance of change in the single walk distance, indicating better precision. Conclusions: Adding a second walk to the 6-min walk test significantly improves its performance in measuring response to a therapeutic intervention, improves the validity of COPD clinical trials, and would result in a 14% to 33% reduction in sample size requirements. Hence, it should be strongly considered by clinicians and researchers as an outcome measure for therapeutic interventions in patients with COPD.
UR - http://www.scopus.com/inward/record.url?scp=84870624079&partnerID=8YFLogxK
U2 - 10.1378/chest.11-2702
DO - 10.1378/chest.11-2702
M3 - Article
C2 - 23364913
AN - SCOPUS:84870624079
SN - 0012-3692
VL - 142
SP - 1545
EP - 1552
JO - CHEST
JF - CHEST
IS - 6
ER -