Overview of patient-reported health-related quality of life instruments27,28,29,30,31,32.
| Instrument | Description | Assessment | MCID |
|---|---|---|---|
| Global disease activity and pain by VAS | Disease activity and pain scales | 0–100 mm, include “anchors” | Improvement: 10.0 points |
| HAQ-DI | Functional ability questionnaire | 0–3 (0 = no difficulty, 3 = unable to do) | Improvement: −0.13 points* and −0.3 points* |
| FACIT-F | Fatigue questionnaire; 13 questions evaluated on 5-point scale | 0–4 (0 = not at all, 4 = very much) | Improvement: 4.0 |
| SF-36 domains | Self-administered instrument assessing 8 health domains: (1) PF: limitations in physical activities; (2) RP: limitations in usual role activities; (3) BP: bodily pain; (4) GH: general health perceptions; (5) VT: vitality; (6) RE: limitations in usual role activities; (7) SF: limitations in social activities; (8) MH: general mental health | 0–100 points, worst to best | Improvement: 5.0 points Deterioration: −2.5 points |
| SF-36 physical and mental component summary scores (PCS and MCS) | Summarizes SF-36 subscale scores | 0–50 points (normative value = 50, SD 10) | Improvement: 2.5 points Deterioration: −0.8 points |
| SF-6D (utility-based measure) | Preference-based measure derived from the SF-36; yields a single score that qualifies changes across all 8 SF-36 domains | 0.296–1.0 (0 = death, 1.0 = perfect health) | MID ≥ 0.041 |
↵* MCID for HAQ-DI was analyzed using 2 different definitions based on 2 published MCID levels in PsA: −0.1331 and −0.332. The present study population more closely resembles the population studied in Kwok, et al31 (MCID, −0.13); however, the more stringent level reported by Mease, et al32 (MCID, −0.3) was included for comparative purposes. FACIT-F: Functional Assessment of Chronic Illness Therapy for Fatigue; HAQ-DI: Health Assessment Questionnaire Disability Index; MCID: minimum clinically important differences; MCS: mental component summary; MID: minimum important differences; PCS: physical component summary; SF-36: 36-Item Medical Outcomes Study Short-Form Health Survey, version 2; SF-6D: 6-Domain Short-Form Health Survey; VAS: visual analog scale.