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Table 4 Construct validity: E-RS and wheeze Spearman correlations with SGRQ and clinical assessments

From: Reliability, validity and responsiveness of E-RS:COPD in patients with spirometric asthma-COPD overlap

  Baseline week (Day − 7 to Day − 1) Final treatment week (Day 21 to Day 28)
SGRQ: Total SGRQ: Activity SGRQ: Impacts SGRQ: Symptoms Rescue medication use Morning PEF FEV1 FEV1% predicted SGRQ: Total SGRQ: Activity SGRQ: Impacts SGRQ: Symptoms Rescue medication use Morning PEF FEV1 FEV1% predicted
N 326 328 329 327 336 338 338 338 321 324 325 325 326 327 327 327
RS-Total 0.46 0.43 0.36 0.39 0.33 −0.30 −0.18 −0.17 0.52 0.54 0.40 0.43 0.40 −0.27 − 0.18 − 0.17
RS-Cough and Sputum 0.32 0.29 0.22 0.35 0.26 −0.23 −0.11 − 0.11 0.38 0.36 0.29 0.44 0.34 − 0.16 − 0.11 − 0.10
RS-Chest Symptoms 0.37 0.32 0.3 0.33 0.29 − 0.19 −0.06 − 0.05 0.45 0.43 0.37 0.39 0.32 −0.18 − 0.09 − 0.08
RS-Breathlessness 0.48 0.48 0.38 0.35 0.33 −0.33 −0.24 − 0.22 0.53 0.59 0.42 0.38 0.40 −0.31 −0.23 − 0.23
Wheeze 0.38 0.33 0.29 0.41 0.33 −0.12 0.01 −0.11 0.42 0.38 0.34 0.43 0.32 −0.12 −0.04 − 0.06
  1. Weak, moderate and strong correlations were defined as r ≤ 0.4 (unmarked), r > 0.4 (bold) and r > 0.7 (none present in this table), respectively
  2. E-RS Evaluating Respiratory Symptoms in chronic obstructive pulmonary disease, FEV1 forced expiratory volume in 1 s, PEF peak expiratory flow, RS respiratory symptoms, SGRQ St George’s Respiratory Questionnaire