Predictive Value of the COPD Assessment Test Combined with Five-Repetition Sit-to-Stand Test for Impaired Exercise...

This study aimed to determine the longitudinal trends of impaired exercise tolerance in patients with chronic obstructive pulmonary disease (COPD) and to evaluate the predictive value, agreement, and longitudinal stability of the COPD Assessment Test (CAT) combined with the the Five-Repetition Sit-to-Stand Test (5STS) in relation to cardiopulmonary exercise testing.

This exploratory, prospective, 12-month cohort study consecutively enrolled 100 patients with stable COPD who attended the outpatient clinic of the Department of Respiratory and Critical Care Medicine at China-Japan Friendship Hospital from January 2021 to October 2025. Impaired exercise tolerance group was defined as a predicted percentage of peak oxygen uptake (peak VO_2pred) < 85%, as measured by CPET. Patients were evaluated for Physical Fitness at baseline and 12 months using the following tools: modified Medical Research Council (mMRC) questionnaire, CAT score, 5STS, Hand Grip Strength (HGS), Timed Up and Go (TUG) test, and Quadriceps maximal voluntary contraction (QMVC).

At baseline, 58% of COPD patients exhibited impaired exercise tolerance. A statistically significant difference (P < 0.05) was observed in CAT score and 5STS results between the impaired exercise tolerance group and the normal exercise tolerance group. The combined CAT score and 5STS demonstrated a sensitivity of 52.5%, a specificity of 92.7%, and an area under the receiver operating characteristic curve (AUC) of 0.759 (95% CI: 0.666-0.852, P < 0.001) for identifying impaired exercise tolerance, indicating that this combination is most effective for ruling in the impairment. Agreement analysis with peak VO_2pred demonstrated that the CAT score and 5STS showed fair agreement, with consistently moderate predictive value across all time points.

The combined application of the CAT score and the 5STS provides both screening and longitudinal monitoring capabilities, indicating potential for identifying patients with COPD at high risk of impaired exercise tolerance in primary care.