Summary of activity instruments used in studies of acute gout. The properties of the 2 methods used most frequently have been shown because no other methods have been used in > 1 study. No articles reported internal validity, feasibility, or test-retest reproducibility. Effect size (ES) is provided wherever possible. If the ES could not be calculated, the statistic and associated p value are provided. References are represented as numerals in parentheses.
| Method | Description | No. and Type of Studies with References | Feasibility | Truth | Within-group Discrimination (ES) | Between-group Discrimination (estimate or statistic with p-value) |
|---|---|---|---|---|---|---|
| Health Assessment Questionnaire (HAQ) | 0–3 composite scale (0 = no disability, 3 = complete disability) | Total: 2; controlled: 1 (18) using 20 item HAQ-DI; observational: 1 (26) using 10 item HAQ-II | Inexpensive, no training required, no specialist equipment required, acceptable to patients | High face validity. Improvement in the HAQ-DI score was accompanied by similar reductions in joint tenderness and swelling, pain score, C-reactive protein, and PGART (18). Improvement in HAQ csores was accompanied by similar improvements in other mesures of disability including the SF-36 PF score (18), Leeds Foot Impact Scale, and the Lower Limb Task Questionnaire (26). Unable to calculate correlation coefficients with available information. Measure has been endorsed by OMERACT for use in chronic gout studies (7). | Both articles reported significant reduction in HAQ scores over time. In an observational study, mean (SD) HAQ-II score reduced from 1.9 (0.6) at baseline to 0.9 (0.6) at the followup visit (> 1 mo after treatment). ES = 1.43 (26). In an RCT of canakinumab (CAN) vs triamcinolone acetonide (TA), reductions in HAQ-DI scores ranged from 0.46–0.67 at Day 7, and 0.52–0.85 at Week 8 across the groups (18). | In an RCT of CAN vs TA, there was no significant difference between the treatment groups in HAQ-DI scores over time (18). |
| Medical Outcomes Study Short Form-36 (SF-36) physical function (PF) domain | Scores range from 0 to 100, where 0 represents the worst possible physical function and 100 is perfect physical function | Total: 2; controlled: 2 (18): SF-36 PF reported, (44) SF-36 PF not reported separately observational: 0 | Licensed, no training required, no specialist equipment required, acceptable to patients | High face validity. Improvement in SF-36 PF score (compared to baseline) was accompanied by reductions in pain, PGART, joint tenderness, swelling, and erythema (18). Unable to calculate correlation coefficients with available information. SF-36 questionnaire has been endorsed by OMERACT for measurement of health-related quality of life in chronic gout studies (3). | In an RCT of CAN vs TA, improvements in SF-36 PF scores were observed in both groups. Mean SF-36 PF scores rapidly improved in the CAN 150 mg group from 41.5 at baseline to 80.0 at 7 days post-dose (a mean increase of 39.0 points), and exceeded the value for the US general population by 8 weeks post-dose (86.1 vs 84.2 for the US general population) (18). ES could not be calculated from available data. | In patients with acute gout, mean SF-36 PF scores were much lower than those for the general US population: 31.1 to 41.5 (US general population, 84.2) (18). In an RCT of CAN vs TA, differences between SF-36 PF scores were not reported between groups over time (18) |
DI: Disability Index; PGART: patient global assessment of response to treatment; OMERACT: Outcome Measures in Rheumatology Clinical Trials; RCT: randomized controlled trials.