Cross-sectional analysis of the reporting of continuous outcome measures and clinical significance of results in randomized trials of non-pharmacological interventions

BACKGROUND Reporting the scoring details of continuous outcome measures in randomized trials allows readers to interpret the size of any effect of the intervention. This study aimed to determine, in a sample of randomized trials: 1) the completeness of reporting of scoring details for continuous outcome measures, and 2) whether trial authors comment on the clinical significance of statistically significant trial results. METHODS A descriptive analysis of randomized trials of non-pharmacological interventions published during 2009 in the six leading general medical journals (n = 138), and which used at least one continuous outcome measure (n = 85). From each trial report, two authors independently extracted the following information about each continuous outcome measure: the reporting of its scoring details, presentation of its results, and the reporting and justification of the clinical significance of the results. RESULTS Across the 84 trials, we identified 336 continuous outcome measures. A total of 146 (44%) were published measures, 12 (4%) were adapted from published measures, 5 (1%) were developed for the trial, and 173 (51%) were 'conventional measures' for which scoring details are not necessary (such as weight). For 57 (35%) of the 163 non-conventional outcome measures no scoring details or reference to the outcome measure were provided in the trial report. Of the 159 outcome measures with a statistically significant result, clinical significance was not mentioned for 81 (51%) and was reported without any elaboration or justification for 39 (25%) of them. CONCLUSIONS Scoring details of continuous outcome measures used in this sample of randomized trials of non-pharmacological interventions were incompletely reported, which hampers interpretation of a trial's results. Complete reporting of scoring details is important when considering the clinical significance of the results. When deciding about an intervention, having this information may help clinicians in their conversations with patients about the possible benefits and harms, and their size, of the intervention.