Table 2.
Studied Measurement Characteristics of Patient Reported Outcomes in Psoriatic Arthritis
| Patient Reported Outcome |
Populatio n |
Reliabilit y Internal consiste ncy |
Reliabil ity e.g. test- retest |
Measurem ent error |
Conten t validity |
Construct validity |
Criterio n validity |
Responsiven ess |
Interpretabi lity (existence of cutoffs) |
|---|---|---|---|---|---|---|---|---|---|
| Medical Outcomes Study Short Form-36 (SF-36) | general | Cronbach’s alpha >0.8 for all 8 scales (25) | NR | NR | NR | Hypothesis testing based on
convergent/divergent validity (25) Structural validity of PCS and MCS dimensions with confirmatory factor analysis (76) |
NR | Area under Receiver Operator Curve (77) | PsA MID calculated (13) |
| Euro-Qol 5 Dimensions (EQ-5D) | general | NR | NR | NR | NR | NR | NR | NR | NR |
| PsA Quality of Life Index (PsAQoL) | psoriatic arthritis | Internal consistency 0.91 Rasch analysis: person separation index 0.93 (27) |
Test retest reliability 0.89 (27) | NR | qualitative research | Hypothesis testing convergent validity (27) | NR | NR | NR |
| Dermatologic Life Quality Index (DLQI) | dermatological conditions | NR | NR | NR | NR | NR | NR | NR | NR |
| Psoriatic Arthritis Impact of Disease (9 and 12 item) | psoriatic arthritis | Cronbach’s alpha=0.93–0.94 (4) | Test-retest reliability at 2–10 days ICC 0.95 and 0.94 (4) | NR | Patient prioritized domains (4) | Hypothesis testing convergent validity (4) | NR | Provided SRM (4) | Preliminary
values PASS=4 MCII=3 (4) |
| Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) | ankylosing spondylitis | NR | NR | NR | NR | Hypothesis testing correlation w disease activity (45, 46) | NR | Area under Receiver Operator Curve calculated for predicting high disease activity/change in treatment (46) | NR |
| Health Assessment Questionnaire Disability Index (HAQ-DI) | rheumatoid arthritis | NR | NR | NR | NR | NR | NR | Area under Receiver Operator Curve calculated (77) | PsA MID 0.131 (78) PsA MCII 0.35 (51) |
| Disabilities of arm, shoulder and hand questionnaire (DASH) | rheumatoid arthritis | NR | NR | NR | NR | Hypothesis testing, correlations with disease activity measures (55) | NR | NR | NR |
| Psoriasis Symptom Inventory (PSI) | psoriasis | Cronbach’s alpha =0.95–0.97 (63) | Test re-test (0–2 week and 2–4 week) ICC=0.7 and 0.87 (63) | (psoriasis) Limits of agreement (62) | Qualitative research | Structural validity using confirmatory factor
analysis and Rasch analysis:
uni-dimensionality Hypothesis testing correlations w BSA, SF-36 (63) |
NR | Comparison of PSI change scores w change in patient global (63) | NR |
| Functional Assessment Chronic Illness Therapy-Fatigue (FACIT-F) | cancer | Cronbach’s alpha =0.96 (66) | Test – retest ICC=0.95 (66) | NR | NR | Hypothesis testing (66) | Correlation with Fatigue Severity Scale =−0.79 | NR | No PsA MID RA MID is 4 |
| Work Productivity Survey (WPS) | rheumatoid arthritis | NR | NR | NR | Literature review | Hypothesis testing (72) | NR | Report SRM (72) | NR |