Table 2.
Distribution and reliability of PDQ-39 scoresa
| PDQ-39 dimension/index | Mean (SD)b | Median (inter-quartile)c | Floor/ceiling effect (%)d | Cronbach’s αe | Test-retest ICCf | Success/total | Scaling success rate (%)g |
| Mobility | 33.73 (28.12) | 30.0 (10.0, 52.5) | 12.7/1.4 | 0.86 | 0.77 | 73/80 | 91.25 |
| Activities daily living | 28.35 (27.37) | 20.8 (4.2, 41.7) | 16.9/4.2 | 0.87 | 0.82 | 44/48 | 91.67 |
| Emotional well-being | 31.57 (22.29) | 25.0 (16.7, 45.8) | 4.2/0 | 0.87 | 0.62 | 42/48 | 87.50 |
| Stigma | 24.56 (27.49) | 18.8 (0, 37.5) | 32.4/1.4 | 0.88 | 0.67 | 29/32 | 90.63 |
| Social support | 19.48 (22.67) | 16.7 (0, 33.3) | 43.7/0 | 0.87 | 0.56 | 9/24 | 37.50 |
| Cognitions | 35.65 (21.74) | 31.3 (18.8, 43.8) | 2.8/2.8 | 0.87 | 0.71 | 8/32 | 25.00 |
| Communication | 28.64 (27.01) | 16.7 (0, 58.3) | 26.8/0 | 0.86 | 0.77 | 19/24 | 79.17 |
| Bodily discomfort | 35.09 (23.98) | 25.0 (16.7, 50.0) | 8.5/1.4 | 0.87 | 0.82 | 18/24 | 75.00 |
| PDQ-39 summary index | 29.63 (17.35) | 29.1 (15.1, 39.6) | 0/0 | 0.84 | 0.82 | ||
a
All data, except for test-retest reliability, were from the first time
b
Scores for all dimensions/summary indexes range from 0 to 100, with higher score indicating worse health-related quality of life (HRQOL)
c
The first figure in the bracket is P25 (the 25th percentile) and the second figure in the bracket is P75 (the 75th percentile)
d
Percentage scoring 0 (floor) and 100 (ceiling) should not exceed 15%
e
n=71
f
n=68. Agreement model intra-class correlation coefficients (ICC) from scores of patients completing both administrations (7-d interval)
g
Percentage of occasions when items correlated significantly stronger with their proposed scale than with other scales