Background: The recent ORBIT (Outcome Reporting Bias in Trials) study has shown that outcome reporting bias is an under-recognised problem that affects the conclusions of efficacy outcomes in a substantial proportion of Cochrane reviews [1]. Selective reporting of harms is expected, however there is a lack of research regarding whether standards for assessment and reporting of harms are being followed.

Objectives: To examine the assessment and reporting of harms in clinical studies, and to examine the impact of selective reporting of harms in clinical trials on systematic reviews.

Methods: We refer to three studies that demonstrate the problem and potential impact of poor reporting of harms: the ADRiC (Adverse Drug Reactions in Children) systematic review; further results from the ORBIT study; and a case study meta-analysis demonstrating the effect on the benefit-harm ratio.

Results: Results from the ADRiC systematic review showed that the reporting of ADRs, in studies where detection of ADRs was a primary aim, was poor, with only 3/101 studies including data on causality, predictability and avoidability. The findings from the interviews from the ORBIT study provides an explanation of why selective reporting occurs in relation to harms. Poor reporting of gastro-intestinal bleeds in trials of aspirin is shown to affect the benefit-harm ratio.

Conclusions: This presentation will provide a forum for discussion of the procedures for assessing and reporting harms in clinical trials. This will improve the ability of decision makers to make informed decisions that consider both benefits and harms of an intervention, ultimately improving patient safety.

Reference

1. Kirkham JJ, Dwan KM, Altman DG, Gamble C, Dodd S, Smyth R, Williamson PR. The impact of outcome reporting bias in randomised controlled trials on a cohort of systematic reviews. BMJ (2010); 340: c365. doi: 10.1136/bmj.c365.