Summary of case studies.
| Outcome Topic [Author] | Focus | What are the outcome domains you are currently working with? | How were the outcome instruments selected? | How was face validity assessed? | How was content validity assessed? | How was construct validity assessed? |
|---|---|---|---|---|---|---|
| Fatigue/Sleep [SH/GAW] | Fatigue | Bristol RA Fatigue Scales | Final 20 items selected from repeated factor analysis in large RA cohort | 45 draft items obtained from qualitative interviews with RA patients on fatigue | 45 draft items obtained from qualitative interviews with RA patients on fatigue | Associations with expected related variables in comparison with performance of best existing fatigue PROM |
| Gout [JS] | Chronic gout | Pain; joint swelling; joint tenderness; patient global; activity limitations | A previously used physician-judged joint swelling Likert scale was used | Previous use in other inflammatory arthritis conditions like rheumatoid arthritis | Previous use in other inflammatory arthritis conditions like rheumatoid arthritis | Correlation with joint tenderness, pain, and patient global |
| MRI in RA [MO] | Rheumatoid arthritis magnetic resonance imaging score (RAMRIS) | Synovitis; bone marrow edema (osteitis); bone erosion; joint space narrowing | Consensus among experts, followed by iterative testing in cross-sectional and longitudinal multireader exercises with group discussions in between Comparison with physician expert panel recommendations and with the results of an ongoing patient interview qualitative study about meaning of stiffness and the burden of PMR | By subjective evaluation of the credibility (whether the measures appeared to measure what they were supposed to) among rheumatologist, radiologists, and metrologists | By subjective evaluation among rheumatologist, radiologists, and metrologists of whether the measures covered all aspects of the attribute to be assessed (comprehensiveness) | Synovitis and bone marrow edema: By comparison with clinical and biochemical (CRP) measures of inflammation. Bone erosion and JSN: By comparison with radiography and computed tomography |
| PMR [CD/JK] | Polymyalgia rheumatica | Pain; stiffness; function; systemic inflammation | Candidate outcome measures identified for a postulated future interventional trial of an alternative to morning prednisolone for PMR through a systematic review of RCT and longitudinal observational studies in PMR to identify outcome measures reported. The instruments are generic and have not been validated for PMR specifically. | Within reported studies, correlations between reported measures of outcome were sought, particularly within patient-reported measures, within laboratory measures of pathophysiology, and between these 2 groups | ||
| Worker productivity [AB/DB] | Instruments to measure presenteeism (being at work while ill) | Work outcomes in inflammatory rheumatic disease (and osteoarthritis) | A systematic review of the literature to identify instruments that measure presenteeism in studies on patients with inflammatory disease (or osteoarthritis) | Careful assessment of (1) the stated objective to develop the instrument; (2) the instrument itself. ↓ Then classifying instruments as (1) those aiming to quantify the “productivity for the workplace” vs those aiming to assess the “difficulty or ability of the patients;” and (2) either multidimensional (usually addressing difficulty) or single item (most frequently addressing productivity) | (1) For the multidimensional instruments, content was linked to the nearest fitting ICF category; (2) for the single item instruments: (a) survey among clinicians, and economic researchers: does this instrument assess productivity, ability/difficulty or both? (b) cognitive debriefing: do patients understand the construct? (further non-English–speaking culture debriefing planned) | (1) Against measure of disease burden: disease activity, activities, other social roles, and (2) against other measures of work outcome; either presenteeism or sick leave |
RA: rheumatoid arthritis; PROM: patient-reported outcome measures; CRP: C-reactive protein; JSN: joint space narrowing; PMR: polymyalgia rheumatica; RCT: randomized controlled trial; ICF: International Classification of Functioning, Disability, and Health.