Background
Methods
Translation of the ASQoL
Field-testing for face and content validity
Psychometric validation
Cross-sectional study
ASQoL [3]
Health Assessment Questionnaire (HAQ) [24]
Short form-36 health survey (SF-36) version 2 [26]
The bath indices [29‐31]
Statistical analyses
Rasch model analysis
Test-retest reliability study
Results
Translation of the ASQoL
Field-testing for face and content validity
Psychometric validation
Age (years) | ||
Mean (SD) | 39.5 (13.7) | |
Gender | n | % |
Male | 141 | 77.0 |
Female | 42 | 23.0 |
Marital Status | ||
Single | 72 | 39.3 |
Married | 103 | 56.3 |
Divorced/Separated | 7 | 3.8 |
Widowed | 1 | 0.5 |
Education | ||
Primary or below | 6 | 33 |
Secondary | 45 | 24.6 |
Post-secondary | 66 | 36.1 |
Tertiary | 65 | 35.5 |
missing | 1 | 0.5 |
Work status | ||
Employed/ self employed | 128 | 69.9 |
Student | 19 | 10.4 |
Housekeeper | 10 | 5.5 |
Retired | 8 | 4.4 |
Unemployed | 16 | 8.7 |
missing | 2 | 1.1 |
Administered Language | ||
English | 150 | 82.0 |
Chinese | 33 | 18.0 |
Ethnicity | ||
Chinese | 156 | 85.2 |
Malay | 5 | 2.7 |
Indian | 9 | 4.9 |
Others | 13 | 7.1 |
Mean (SD) | % ceiling (Best score) | % Floor (Worse score) | |
---|---|---|---|
ASQoL | 4.6 (4.2) | 19.1 | 0 |
Pain VAS (0–100) | 35.0 (25.1) | 3.3 | 0 |
PGA (0–100) | 37.6 (24.5) | 3.3 | 0 |
PhGA (1–5) | 2.3 (0.9) | 0 | 0.5 |
BASDAI (0–100) | 33.1 (18.2) | 0.5 | 0 |
BASFI (0–100) | 20.5 (20.1) | 12 | 0 |
BAS–G (0–100) | 38.9 (21.6) | 2.2 | 0 |
HAQ (0–3) | 0.28 (0.39) | 42.6 | 0 |
SF–36 PCS (norm-based) | 42.9 (11.8) | NA | NA |
SF–36 MCS (norm-based) | 43.7 (12.3) | NA | NA |
ASQoL Spearman’s rank correlation coefficient | |
---|---|
Pain VAS | 0.50* |
PGA | 0.43* |
PhGA | 0.44* |
BASDAI | 0.50* |
BASFI | 0.44* |
BAS-G | 0.46* |
HAQ | 0.53* |
SF36 | |
Physical Functioning | −0.60* |
Role Physical | −0.60* |
Bodily Pain | −0.60* |
General Health | −0.59* |
Vitality | −0.63* |
Social Functioning | −0.64* |
Role Emotional | −0.67* |
Mental Health | −0.55* |
Physical Component Summary | −0.60* |
Mental Component Summary | −0.58* |
Rasch model analysis
Item | Item Calibration in logits (SE) | INFIT (MNSQ) | OUTFIT (MNSQ) | DIF Probability by Mantel-Haenszel statistics (p) | ||
---|---|---|---|---|---|---|
Gender | Agea
| Languageb
| ||||
#1 | −0.64 (0.20) | 1.14 | 1.25 | 0.4381 | 0.0074 | 0.7937 |
#2 | 0.48 (0.23) | 0.99 | 0.89 |
0.0005
| 0.9200 | 0.5870 |
#3 | 1.56 (0.30) | 1.08 | 0.93 | 0.5964 | 0.0037 | 0.6836 |
#4 | 0.63 (0.24) | 0.80 | 0.69 | 0.9713 | 0.2586 | 0.9458 |
#5 | 1.09 (0.26) | 0.87 | 0.78 | 0.7520 | 0.0476 | 0.9763 |
#6 | −0.51 (0.20) | 1.07 | 1.14 | 0.6056 | 0.8955 | 0.1197 |
#7 | −0.58 (0.20) | 0.95 | 0.87 | 0.0476 | 0.2484 | 0.0850 |
#8 | −0.85 (0.20) | 0.78 |
0.68
| 0.5995 | 0.9560 | 0.8635 |
#9 | 1.02 (0.26) | 0.90 | 0.72 | 0.5301 | 0.5218 | 0.1634 |
#10 | 0.32 (0.23) | 0.94 | 1.01 | 0.0631 | 0.9597 | 0.1467 |
#11 | 1.94 (0.33) | 1.09 | 0.95 | 0.5933 | 0.6896 | 0.3634 |
#12 | −1.61 (0.20) | 0.86 | 0.74 | 0.1651 | 0.0992 | 0.0293 |
#13 | −0.55 (0.20) | 0.89 | 0.97 | 0.4904 | 0.1512 | 0.6042 |
#14 | −1.69 (0.20) |
1.45
|
1.66
| 0.7045 | 0.6147 | 0.0397 |
#15 | −0.51 (0.20) | 0.92 | 0.82 | 0.6857 | 0.2089 | 0.0286 |
#16 | 2.44 (0.38) | 1.00 | 1.29 | 0.4703 | 0.0555 | 0.1191 |
#17 | −1.31 (0.20) | 1.13 | 1.12 | 0.4670 | 0.9162 | 0.9222 |
#18 | −1.23 (0.20) | 1.04 | 0.95 | 0.5116 | 0.2195 | 0.7969 |
Observed data | Simulated data 1 | Simulated data 2 | |
---|---|---|---|
Total raw variance in observations | 100% | 100% | 100% |
Raw variance explained by Rasch model | 37.2% | 38.8% | 38.4% |
Raw variance explained by persons | 16.1% | 17.4% | 16.8% |
Raw variance explained by items | 21.1% | 21.3% | 21.5% |
Raw unexplained variance (total) | 62.8% | 61.2% | 61.6% |
Unexplained variance in first contrast in Eigenvalue, (%) | 2.077 (7.2%) | 1.67 (5.7%) | 1.69 (5.8%) |