Identifying COPD patients with poor health status and low exercise tolerance through the five-repetition sit-to-stand test and modified Medical Research Council Dyspnea Score

•Health status and exercise tolerance are relevant non-pulmonary markers for patients with COPD.•The differential characteristics of subjects with both poor health status (CAT score ≥ 10 points) and low exercise tolerance (6MWT < 350 m) have not been explored yet.•Our results evince a worse clinical profile among patients with both conditions (i.e., high CAT score and low performance in the 6MWT).•The model developed from these combined measures but using surrogate measures (mMRC and 5STS) is highly efficient. The objective of this study was to determine whether the concomitant presence of poor health status (COPD Assessment Test, CAT ≥ 10 points) and low exercise tolerance (6-Minute Walking Test, 6MWT < 350 m) is associated with worse clinical characteristics in patients with COPD. In addition, we aimed to develop a readily applicable diagnostic model to discriminate COPD patients with these conditions. A cross-sectional multicenter study involving 208 stable COPD patients (FEV1/FVC < 0.7, smoking history of at least 10 pack-years, and chronic respiratory symptoms) was carried out. The outcome measures were the 6MWT, CAT score, 5-repetition sit-to-stand test (5STS) and modified Medical Research Council Dyspnea Scale (mMRC). Patients were categorized into three groups: no condition (6MWT ≥ 350 m and CAT < 10 points), one condition (6MWT < 350 m or CAT ≥ 10 points), and both conditions (6MWT < 350 m and CAT ≥ 10 points). A total of 26 patients (12,5%) presented both conditions. These patients experienced a higher degree of dyspnea (p = 0.001), smoking pack-years (p = 0.011), severe obstruction (p = 0.006), and time on 5STS (p = 0.001). The probability of having both conditions directly increased with the time spent on the 5STS (β=0.188; p = 0.010) and the degree of dyspnea (β=1.920; p < 0.001) (R2=0.413). The scoring system, using the 5STS and dyspnea as surrogate measures, demonstrated adequate calibration between the predicted and observed risk (linear R2=0.852). COPD patients with concurrent conditions have worse clinical status. The diagnostic model developed to discriminate these patients shows good internal validation.