Discriminant Validity of a Single Clinical Question for the Screening of Inactivity in Individuals Living with COPD

Abstract

Introduction

Quantifying physical activity in chronic obstructive pulmonary disease (COPD) with questionnaires and activity monitors in clinical practice is challenging. The aim of the present study was to analyse the discriminant validity of a single clinical question for the screening of inactive individuals living with COPD.

Methods

A multicentre study was carried out in stable COPD individuals both in primary and tertiary care. Patients wore the Dynaport accelerometer for 8 days and then answered 5 physical activity questions developed for the study, referring to the week in which their physical activity was monitored. Receiver operating characteristic (ROC) curve analysis with physical activity level (PAL) as the gold standard reference was used to determine the best cut-off point for each of the 5 clinical physical activity questions tested.

Results

A total of 86 COPD participants were analysed (males 68.6%; mean (SD) age 66.6 (8.5) years; FEV₁ 50.9 (17.3)% predicted; mean of 7305 (3906) steps/day). Forty-two (48.8%) participants were considered physically inactive (PAL ≤1.69). Answers to 4 out of 5 questions significantly differed in active vs inactive patients. The Kappa index and ROC curves showed that the answer to the question “On average, how many minutes per day do you walk briskly?” had the best discriminative capacity for inactivity, with an area under the curve (AUC) (95% Confidence interval (CI)) of 0.73 (0.63–0.84) and 30 min/day was identified as the best cut-off value (sensitivity (95% CI): 0.75 (0.60–0.87); specificity: 0.76 (0.61–0.88)).

Conclusion

The present results indicate that self-reported brisk walk time lower than 30 min/day may be a valid tool for the screening of inactivity in individuals living with COPD in routine care, if more detailed physical activity measures are not feasible.

Keywords:

• chronic obstructive pulmonary disease
• physical activity
• outcome assessment
• validation studies

Abbreviations

ATS, American Thoracic Society; AUC, Area under the curve; BMI, Body mass index; BODE, Body mass index, obstruction, dyspnoea and exercise index; CAT, COPD assessment test; CI, Confidence interval; COPD, Chronic obstructive pulmonary disease; ERS, European Respiratory Society; FEV_1, Forced expiratory volume in one second; FVC, Forced vital capacity; GLI, Global lung function initiative; HADs, Hospital anxiety and depression scale; ICC, Intraclass correlation coefficient; MET, Metabolic equivalents; mMRC, Modified Medical Research Council; PAL, Physical activity level; ROC, Receiver operating characteristic; SD, Standard deviation; 6MWD, 6-min walking distance.

Acknowledgments

The following investigators participated in the study: Eduardo Loeb, Alexa Nuñez (Hospital Universitari Vall d’Hebron, Barcelona), Eva Tabernero (Hospital de Cruces, Bilbao), Raúl Galera, Raquel Casitas (Hospital Universitario La Paz, Madrid), José Espinoza, Pablo Sánchez, Izaskun Jiménez, Déborah Jorge (Hospital CH de Navarra, Pamplona), Violeta Esteban Ronda (Hospital Arnau de Vilanova-Lliria, Valencia).

Disclosure

Cristóbal Esteban has received speaker fees from AstraZeneca, Boehringer Ingelheim, Chiesi and GlaxoSmithKline. Ines Carrascosa has received speaker fees from AstraZeneca, Boehringer Ingelheim, GlaxoSmithKline, Sandon, Pfizer and, consulting fees from CSL BEHRING and Sanofi. Patricia Sobradillo has received speaker fees from AstraZeneca, Bial, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Menarini, Rovi, TEVA and Novartis, consulting fees from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline and Laboratorios Esteve. Juan José Soler-Cataluña has received speaker fees from AstraZeneca, Bial, Boehringer Ingelheim, Chiesi, Menarini, Novartis, and Teva, and consulting fees from AstraZeneca, Bial, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Novartis. Marc Miravitlles has received speaker fees from AstraZeneca, Boehringer Ingelheim, Chiesi, Cipla, GlaxoSmithKline, Menarini, Rovi, Bial, Sandoz, Zambon, CSL Behring, Jansen, Kamada, Grifols and Novartis, consulting fees from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline, Bial, Gebro Pharma, Kamada, CSL Behring, Laboratorios Esteve, Ferrer, Mereo Biopharma, Palobiofarma SL, Takeda, Verona Pharma, TEVA, Spin Therapeutics, pH Pharma, Novartis, Sanofi and Grifols and research grants from Grifols. Francisco García-Río has received speaker fees from AstraZeneca, Boehringer Ingelheim, Chiesi, Menarini, Rovi, Sanofi and Novartis, consulting fees from AstraZeneca, Boehringer Ingelheim, Chiesi, GlaxoSmithKline and Laboratorios Esteve, and research grants from GlaxoSmithKline, Menarini, ROCHE Pharma and Chiesi. The remaining authors have no conflicts of interest to disclosure.

Additional information

Funding

This study was funded by an unrestricted grant from Laboratorios Esteve (Barcelona, Spain).