Asthma | Asthma+COPD | COPD | Total sample | |
Patients | 510 | 510 | 510 | 1530 |
Factor loadings for RSQ items | ||||
1# | 0.800 | 0.819 | 0.798 | 0.812 |
2¶ | 0.760 | 0.761 | 0.734 | 0.758 |
3+ | 0.814 | 0.820 | 0.806 | 0.817 |
4§ | 0.817 | 0.757 | 0.744 | 0.770 |
Eigenvaluesƒ | ||||
Factor 1 | 2.55 | 2.49 | 2.38 | 2.49 |
Factor 2 | 0.55 | 0.57 | 0.60 | 0.55 |
Variance explained % | 63.7 | 62.4 | 59.4 | 62.4 |
Data are presented as n, unless otherwise stated. COPD: chronic obstructive pulmonary disease; RSQ: Respiratory Symptoms Questionnaire. #: question 1 (“In the past 4 weeks, how often have you had shortness of breath, wheezing, coughing and/or chest tightness during the day?”); ¶: question 2 (“In the past 4 weeks, how often did you use a rescue inhaler (quick relief inhaler) in response to shortness of breath, wheezing, coughing and/or chest tightness?”); +: question 3 (“In the past 4 weeks, how limited were your activities as a result of shortness of breath, wheezing, coughing and/or chest tightness?”); §: question 4 (“In the past 4 weeks, how often did you wake up at night due to shortness of breath, wheezing, coughing and/or chest tightness?”); ƒ: one factor was retained for each analysis based on a factor retention criteria of eigenvalue ≥1.00 (a second factor did not meet this threshold and there were no items with split loadings in a two-factor solution).