Terms used in this evidence summary

Advice

European Scleroderma Study Group disease activity and severity indices

The European Scleroderma Study Group (EScSG) has developed disease activity and severity indices to help assess scleroderma in clinical practice and in clinical trials.

The EScSG disease activity index is a 10‑item index with a maximum score of 10, indicating greater disease activity. There are 3 indices: 1 for systemic sclerosis as a whole, 1 for diffuse systemic sclerosis and for limited systemic sclerosis. Items include skin scores, scleroderma, digital necrosis and arthritis on examination; patient-reported deterioration in various symptoms; and several laboratory tests.

The EScSG disease severity index scores 9 organ systems (general, peripheral vascular, skin, joint and tendon, muscle, gastrointestinal tract, lung, heart and kidney) on a scale of 0 to 4, with higher scores indicating worse disease.

The minimal clinically important treatment effect is unclear for the EScSG disease activity and severity indices. It is also unclear if these indices have been validated.

Health Assessment Questionnaire Disability Index

The Health Assessment Questionnaire Disability Index (HAQ‑DI) is a validated, self-reported questionnaire with 8 categories (dressing and grooming, arising, eating, walking, hygiene, reach, grip, and activity). Each category includes 2 or 3 questions, which are scored from 0 (without difficulty) to 3 (unable to do). Points may also be added if help and aids or devices are required for usual activities. The score for the disability index is the mean of the 8 category scores and higher scores indicate greater disability.

Redelmeier DA et al. (1993) reported that HAQ‑DI scores needed to differ by about 0.19 points for average respondents to stop rating themselves as 'about the same' and start rating themselves as 'somewhat better' (95% confidence interval 0.10 to 0.28). Following a Delphi consensus building exercise, Gazi H et al. (2007) reported that the minimal clinically important treatment effect for the HAQ‑DI ranges from 0.2 to 0.25 units.

Modified Rodnan skin score

The modified Rodnan skin score (mRSS) is a validated measure of skin thickness, with higher scores indicating worse thickening. The skin is palpated in 17 areas (fingers, hands, forearms, arms, feet, legs, thighs, face, chest and abdomen) and scored on a scale of 0–3, where 0 is normal, 1 is mild thickening, 2 is moderate thickening and 3 is severe thickening. The total skin score can range from 0 (no thickening) to 51 (severe thickening in all 17 areas).

Following a Delphi consensus building exercise, Gazi H et al. (2007) reported that, the minimal clinically important treatment effect for the mRSS ranges from 3 to 7.5 units.