Summary of published data concerning the cross sectional validity of SGRQ Total scores in patients with COPD
| Result | References | |
| Physiology | ||
| FEV1 | r= 0.14–0.41 | 19, 25, 34, 55, 57 |
| Bronchial hyperreactivity | r = 0.20 (independent of FEV1) | 61 |
| RV/TLC | r = 0.24 | 33 |
| Pao 2 | r = 0.41–0.48 | 55, 57 |
| Pimax | r = 0.23 | 62 |
| Exercise (6-minute walk) | r = 0.28–0.61 | 19, 25, 57 |
| Exercise (Vo 2max) | r = 0.5 | 37 |
| Symptoms | ||
| Frequency of wheeze (daily v not daily) | Difference = 20.0 units | 25 |
| Presence of chronic bronchitis | Difference = 13.9 units | 25 |
| Breathlessness (Borg at end exercise) | r = 0.53 | 25 |
| Breathlessness (MRC dyspnoea scale) | r= 0.46–0.7 | 25, 30, 57, 63 |
| Frequency of exacerbations (lowv high) | Difference = 14.8 units | 23 |
| Mood state | ||
| Depression | r = 0.57–0.72 | 25, 37, 57 |
| Anxiety | r = 0.40–0.57 | 25, 37, 57 |
| Health resource use | ||
| Readmission to hospital (admittedv not readmitted over 1 year) | Difference = 4.8 units | 64 |
| Days in hospital over 1 year | rho = 0.5 | 18 |
FEV1 = forced expiratory volume in 1 second; RV = residual volume; TLC = total lung capacity; Pao 2 = arterial oxygen tension; Pimax = maximum inspiratory pressure; Vo 2max = maximum oxygen consumption.
The studies presented here are not exhaustive, but the results given are representative of those in the literature, particularly with respect to the maxima and minima.
Note: (1) The sign of the correlation has been ignored, but in each case the direction of difference in SGRQ score was appropriate to the disease marker against which it was tested. (2) All the results shown are significant at p<0.01 except for those obtained with the FEV1 (see text). (3) A difference in score of 4 units is clinically significant.