Range and consistency of outcome measures reported in randomised trials in dermatomyositis: a systematic review

Dermatomyositis (DM) and juvenile dermatomyositis (JDM) are idiopathic inflammatory myopathies, which can be resistant and unresponsive to initial treatments, leading to severe complications and impaired quality of life. There are few randomised trials in dermatomyositis and the outcomes reported may not be consistent, which can limit decision-making. The aim of this study is to assess the scope and consistency of outcomes reported in randomised trials in dermatomyositis.

MEDLINE, Embase, PsycINFO and clinicaltrials.gov were searched from 1993-2020 for randomised trials in children and adults with dermatomyositis. The frequency and characteristics of the outcomes reported were analysed and classified.

20 trials were included. Across these trials, a total of 743 outcome measures were reported, which were grouped into 34 outcome domains; of which 17 were clinical, 13 were surrogate/biochemical, and 4 were patient-reported outcomes. The top five most frequently reported outcome domains were muscle inflammation (15 trials, 46 outcome measures), physical function (14 trials, 16 outcome measures), muscle strength (13 trials, 30 outcome measures), global health (12 trials, 33 outcome measures) and immunologic marker (11 trials, 91 outcomes).

The majority of outcomes reported in trials in people with dermatomyositis and JDM are clinical and surrogate outcomes rather than patient-reported outcomes. The outcomes reported are very inconsistent across trials, with wide heterogeneity in the measures used. Standardised reporting of critically important outcomes is needed to strengthen the value of trials for decision-making.