Introduction
Methods
Study design and recruitment
EuroQol-5-Dimensions 5-Level (EQ-5D-5L)
Asthma Quality of Life Utility Index-5-Dimensions (AQL-5D)
Time Trade-Off (TTO)
Construct validity
- < 50% of the best/predicted PEF (life threatening or acute severe asthma)
- 50–75% of the best/predicted PEF (moderate acute asthma)
- > 75% of the best/predicted PEF (good/very good asthma)
Responsiveness
- Question Compared to your asthma state when you were in hospital approximately 4 weeks ago, how would you rate your asthma now?
- Answers options very good, good, moderate, poor or very poor.
Results
Demographics | N = 121 |
---|---|
Age (mean, years) | 49.68 |
Height (mean, cm) | 167.22 |
Weight (mean, kg) | 85.54 |
Gender (%) | |
Male | 26.45 |
Female | 73.55 |
Ethnicity (%) | |
White | 95.83 |
Mixed white and black | 0.83 |
White other | 3.33 |
Smoking status (%) | |
Never | 42.50 |
Non smoker | 1.67 |
Smoker | 15.00 |
Ex-smoker | 40.83 |
Highest level of education (%) | |
School | 47.06 |
College | 33.61 |
Degree | 19.33 |
Employment status (%) | |
Full-time | 27.50 |
Part-time | 15.83 |
Retired | 28.33 |
Stay at home parents | 7.50 |
Student | 3.33 |
Unemployed | 17.50 |
Convergent validity
EQ-5D-5L (utility) | AQL-5D (utility) | TTO (utility) | |
---|---|---|---|
EQ-5D-5L (utility) | N = 120 | ||
1.0000a | |||
AQL-5D (utility) | N = 118 | N = 118 | |
0.3888a** | 1.0000a | ||
TTO (utility) | N = 111 | N = 109 | N = 112 |
0.1287a | 0.0864a | 1.000a |
EQ-5D-5L (utility) | AQL-5D (utility) | TTO (utility) | PEF | |
---|---|---|---|---|
EQ-5D-5L (utility) | N = 71 | |||
1.0000a | ||||
AQL-5D (utility) | N = 63 | N = 70 | ||
0.5355a** | 1.0000a | |||
TTO (utility) | N = 62 | N = 62 | N = 87 | |
0.1771a | 0.3027a* | 1.000a |
EQ-5D-5L (utility) | AQL-5D (utility) | TTO (utility) | |
---|---|---|---|
EQ-5D-5L (utility) | N = 64 | ||
1.0000a | |||
AQL-5D (utility) | N = 61 | N = 64 | |
0.6260a** | 1.0000a | ||
TTO (utility) | N = 60 | N = 58 | N = 80 |
0.1871a | 0.3087a* | 1.000a |
Discriminative validity
< 50% of best/predicted PEF mean ranka | < 50% of best/predicted PEF N | 50–75% of best/predicted PEF mean ranka | 50–75% of best/predicted PEF N | > 75% of best/predicted PEF mean ranka | > 75% of best/predicted PEF N | p-value* | |
---|---|---|---|---|---|---|---|
EQ-5D-5L utility | 53.64 | 18 | 57.02 | 42 | 71.89 | 27 | 0.105 |
AQL-5D utility | 53.36 | 18 | 56.45 | 42 | 68.96 | 26 | 0.223 |
TTO utility | 49.91 | 16 | 58.11 | 40 | 56.70 | 28 | 0.713 |
Responsiveness
Items | N | Baseline (mean) | Week 4 (mean) | Mean change | SD at baseline | SD at change | ES | SRMb | p valuea |
---|---|---|---|---|---|---|---|---|---|
EQ-5D-5L | |||||||||
Very good | 14 | 0.747 | 0.922 | 0.175 | 0.280 | 0.235 | 0.625 | 0.745** | 0.011 |
Good | 17 | 0.585 | 0.807 | 0.221 | 0.325 | 0.233 | 0.680 | 0.948*** | 0.000 |
Moderate | 24 | 0.630 | 0.724 | 0.094 | 0.265 | 0.239 | 0.355 | 0.393* | 0.031 |
Poor | 8 | 0.604 | 0.328 | − 0.276 | 0.148 | 0.268 | − 1.865 | − 1.030*** | 0.066 |
AQL-5D | |||||||||
Very good | 15 | 0.629 | 0.798 | 0.169 | 0.135 | 0.187 | 1.252 | 0.904*** | 0.010 |
Good | 17 | 0.621 | 0.787 | 0.166 | 0.132 | 0.140 | 1.258 | 1.186*** | 0.001 |
Moderate | 26 | 0.560 | 0.621 | 0.061 | 0.113 | 0.110 | 0.540 | 0.555** | 0.023 |
Poor | 9 | 0.529 | 0.524 | − 0.005 | 0.107 | 0.019 | − 0.047 | − 0.263* | 0.356 |
TTO | |||||||||
Very good | 14 | 0.679 | 0.932 | 0.254 | 0.250 | 0.329 | 1.016 | 0.772** | 0.014 |
Good | 19 | 0.682 | 0.908 | 0.227 | 0.296 | 0.320 | 0.767 | 0.709** | 0.013 |
Moderate | 23 | 0.598 | 0.787 | 0.189 | 0.297 | 0.348 | 0.636 | 0.543** | 0.008 |
Poor | 8 | 0.881 | 0.708 | − 0.173 | 0.177 | 0.376 | − 0.977 | − 0.471* | 0.468 |