| MEASUREMENT PROPERTIES | |
| Limitations | <5 European languages (English) |
| Observations |
To assess the influence of comorbidities on functioning and health in patients with ankylosing spondylitis (AS), the self-administered comorbidity questionnaire (SCQ) was validated in 98 patients with AS in the Outcome in AS International Study (OASIS) . |
| 1. RELIABILITY | |
| A. Internal Consistency | Not Tested |
| Cronbach's (Describe) | |
| B. Reliability intraobserver or test-retest | Tested |
| Continuous scores: intraclass correlation coefficient (ICC) Dichotomus: Cohen kappa (Describe) |
The test-retest was 0.94 as calculated by ICC and 0.81 by the Spearman coefficient |
| C. Reliability interobserver or Measurement error | Not Tested |
| Standard error of measurement (SEM), smallest detectable change (SDC) or Limits of agreement (LoA) (Describe) |
|
| 2. VALIDITY | |
| A. Content validity: face validity | Not Tested |
| Expert opinion (relevance and comprehensiveness) (Describe) |
|
| B. Construct Validity: Structural validity |
Tested |
| Hypotheses-testing | Tested |
| Cross-cultural validity | Tested |
| Brief Description |
The OASIS study showed evidence for criterion and construct validity of the SCQ in patients with long-standing AS, who fulfilled the New York criteria for AS and were under care of a rheumatologist in three tertiary centres in Europe. |
| C. Criterion validity | Not Tested |
| Comparison with a 'gold standard' Continuous scores: correlations, ROC curves Dichotomus: Sensitivity & Specificity (Describe) |
|