Background
Methods
Study sample
Procedure
Definition and severity of COPD
Global Initiative for Chronic Obstructive Lung Disease, GOLD [3]: FEV1/FVC < 70% | ||
---|---|---|
I: | Mild COPD | FEV1 ≥ 80% predicted |
II: | Moderate COPD | FEV1 50- < 80% predicted |
III: | Severe COPD | FEV1 30- < 50% predicted |
IV: | Very severe COPD | FEV1 < 30% predicted |
British Thoracic Society, BTS [2]: FEV
1
/VC < 70% and FEV
1
< 80% predicted
| ||
I: | Mild COPD | FEV1 60- < 80% predicted |
II: | Moderate COPD | FEV1 40-59% predicted |
III: | Severe COPD | FEV1 < 40% predicted |
HRQL questionnaires
Short Form 36
St George's Respiratory Questionnaire
EQ-5D
Statistical analysis
Results
Subject characteristics
Characteristic | Mean data (range) |
---|---|
n, total number agreed | 176 |
Men/women n = 168 | 98/70 |
Mean age, years (range) n = 168 | 64.3 (28–80) |
FEV1, L (range) n = 159 | 1.76 (0.46–4.12) |
FEV1 % predicted (range) n = 159 | 62 (18–118) |
Smoking status n = 171 | Smoker, n = 57 Non-smoker, n = 29 Ex-smoker, n = 85 |
Socioeconomic group n = 174 | Manual employees, n = 78 Non-manual employees, n = 60 Unemployed incl. housewives, n = 36 |
HRQL in relation to COPD severity according to GOLD
Scale | FEV1 % predicted | ||||
---|---|---|---|---|---|
≥ 80% Stage I n = 26
|
79-50% Stage II n = 91
|
49-30% Stage III n = 33
|
< 30% Stage IV n = 9
|
p-value (all stages)
| |
SF-36 PCS | 42(12) | 42(12) | 40(10) | 29(12) | 0.0059 |
SF-36 MCS | 55(8) | 51(11) | 52(12) | 48(18) | 0.19 |
SGRQ Total | 25(20) | 32(20) | 36(20) | 53(23) | 0.0005 |
EQ-5D VAS | 73(21) | 65(24) | 62(21) | 37(28) | 0.0001 |
EQ-5D index | 0.84(0.15) | 0.73(0.23) | 0.74(0.25) | 0.52(0.26) | 0.0008 |
HRQL in relation to COPD severity according to BTS
Scale | FEV1 % predicted | ||||
---|---|---|---|---|---|
≥ 80% Stage 0 n = 26
|
79-60% Stage I n = 63
|
59-40% Stage II n = 47
|
< 40%Stage III n = 23
|
p-value (all stages)
| |
SF-36 PCS | 42(12) | 43(11) | 40(13) | 35(11) | 0.032 |
SF-36 MCS | 55(8) | 50(10) | 54(11) | 50(15) | 0.29 |
SGRQ Total | 25(20) | 32(20) | 34(19) | 45(22) | 0.0023 |
EQ-5D VAS | 73(21) | 68(20) | 60(28) | 50(25) | 0.0007 |
EQ-5D index | 0.84(0.15) | 0.74(0.21) | 0.72(0.28) | 0.63(0.25) | 0.0041 |
Influence of age, gender, smoking status and socio-economic group
HRQL in relation to FVC % predicted
Scale | FVC % predicted | ||||
---|---|---|---|---|---|
> 95% n = 35
|
95-81% n = 33
|
80-66% n = 40
|
< 66% n = 34
|
p-value (all stages)
| |
SF-36 PCS | 44(11) | 45(11) | 38(12) | 35(10) | 0.0008 |
SF-36 MCS | 53(9) | 52(10) | 53(11) | 49(14) | 0.28 |
SGRQ Total | 26(17) | 29(17) | 37(22) | 43(20) | 0.0002 |
EQ-5D VAS | 71(19) | 69(24) | 63(25) | 49(25) | 0.0002 |
EQ-5D index | 0.79(0.18) | 0.80(0.19) | 0.71(0.27) | 0.62(0.26) | 0.0017 |
Correlations between the instruments
SF-36 PCS | SF-36 MCS | SGRQ Total | EQ-5D VAS | EQ-5D index | FEV1 % predicted | FVC % predicted | |
---|---|---|---|---|---|---|---|
SF-36 PCS
| 1.0 | -- | -- | -- | -- | -- | -- |
SF-36 MCS
| 0.22 | 1.0 | -- | -- | -- | -- | -- |
SGRQ Total
| -0.62 | -0.42 | 1.0 | -- | -- | -- | -- |
EQ-5D VAS
| 0.73 | 0.49 | -0.63 | 1.0 | -- | -- | -- |
EQ-5D index
| 0.64 | 0.58 | -0.61 | 0.68 | 1.0 | -- | -- |
FEV
1
% predicted
| 0.30 | 0.10 | -0.34 | 0.38 | 0.26 | 1.0 | -- |
FVC % predicted
| 0.32 | 0.08 | -0.37 | 0.36 | 0.22 | 0.81 | 1.0 |