Primary outcomes reporting in trials of paediatric type 1 diabetes mellitus: a systematic review

OBJECTIVE: Our objective was to systematically review randomised clinical trials (RCTs) of paediatric type 1 diabetes mellitus (T1DM) to assess reporting of (1) primary outcome, (2) outcome measurement properties and (3) presence or absence of adverse events. METHODS: Electronic searches in MEDLINE, EMBASE, CINAHL, Cochrane SR and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were undertaken. The search period was between 2001 and 2017. English-language RCTs on children younger than 21 years with T1DM were selected. We excluded studies of diagnostic or screening tools, multiple phase studies, protocols, and follow-up or secondary analysis of data. RESULTS: Of 11 816 unique references, 231 T1DM RCTs were included. Of total 231 included studies, 117 (50.6%) trials failed to report what their primary outcome was. Of 114 (49.4%) studies that reported primary outcome, 88 (77.2%) reported one and 26 (22.8%) more than one primary outcomes. Of 114 studies that clearly stated their primary outcome, 101 (88.6%) used biological/physiological measurements and 13 (11.4%) used instruments (eg, questionnaires, scales, etc) to measure their primary outcome; of these, 12 (92.3%) provided measurement properties or related citation. Of the 231 included studies, 105 (45.5%) reported that adverse events occurred, 39 (16.9%) reported that no adverse events were identified and 87 (37.7%) did not report on the presence or absence of adverse events. CONCLUSION: Despite tremendous efforts to improve reporting of clinical trials, clear reporting of primary outcomes of RCTs for paediatric T1DM is still lacking. Adverse events due to DM interventions were often not reported in the included trials. Transparent reporting of primary outcome, validity of measurement tools and adverse events need to be improved in paediatric T1DM trials.