International Journal of COPD (Apr 2020)
Easy to Perform Physical Performance Tests to Identify COPD Patients with Low Physical Activity in Clinical Practice
Abstract
Zinka Matkovic,1 Neven Tudoric,1,2 Danijel Cvetko,3 Cristina Esquinas,4 Dario Rahelic,2,5,6 Marko Zarak,7 Marc Miravitlles4 1Department of Internal Medicine, Division of Pulmonary Medicine, Dubrava University Hospital, Zagreb, Croatia; 2University of Zagreb, School of Medicine, Zagreb, Croatia; 3Department of Diagnostic and Interventional Radiology, Dubrava University Hospital, Zagreb, Croatia; 4Pneumology Department, Hospital Universitari Vall d’Hebron/Vall d’Hebron Institut de Recerca (VHIR), CIBER de Enfermedades Respiratorias (CIBERES), Barcelona, Spain; 5Vuk Vrhovac University Clinic for Diabetes, Endocrinology and Metabolic Diseases, Merkur University Hospital, Zagreb, Croatia; 6University of Osijek, School of Medicine, Osijek, Croatia; 7Department of Laboratory Diagnostics, Dubrava University Hospital, Zagreb, CroatiaCorrespondence: Zinka MatkovicDepartment of Internal Medicine, Division of Pulmonary Medicine, Dubrava University Hospital, Avenija Gojka Šuška 6, Zagreb 10000, CroatiaTel/Fax +3851290 2488Email [email protected]: The study investigates which physical performance or muscle function/mass tests significantly correlate with objectively measured physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) and could potentially serve to identify physically inactive COPD patients in routine clinical practice.Methods: A cross-sectional, observational study was conducted in outpatients with moderate to very severe COPD. PA was measured during one week with the StepWatch Activity Monitor®, an ankle-worn accelerometer, and expressed in steps per day. Physical fitness and peripheral muscle function/mass were evaluated by the 4-meter gait speed (4MGS) test, the 6-minute walk distance (6MWD), the 30-second chair stand test (30sCST), the timed up and go test (TUGT), handgrip strength, arm muscle area, calf circumference, the fat-free mass index (FFMI), and ultrasound measurement of the quadriceps muscle. Spearman’s rank correlation analysis and ROC analysis were performed.Results: The study population (N=111, 69% men, mean age 68 years) walked a mean of 8059 steps/day. The daily step count strongly correlated with the 6MWD (rho=0.684, p< 0.001) and moderately with the 4MGS (rho=0.464, p< 0.001), the TUGT (rho= − 0.463, p< 0.001), and the 30sCST (rho=0.402, p< 0.001). The correlation with the FFMI was weak (rho=0.210, p=0.027), while the other parameters did not significantly correlate with the daily step count. The 6MWD had the best discriminative power to identify patients with very low PA defined as < 5000 steps/day (AUC=0.802 [95% CI: 0.720– 0.884], p< 0.001), followed by the TUGT, the 4MGS, and the 30sCST.Conclusion: The 6MWD, the 4MGS, the TUGT, and the 30sCST are easy to perform in any clinical setting and may be used by clinicians in the screening of physically inactive COPD patients.Keywords: chronic obstructive pulmonary disease, physical activity, gait speed, muscle function, muscle mass, exercise capacity