Impact of the Transparent Reporting of Evaluations With Nonrandomized Designs Reporting Guideline: Ten Years On

Objectives. We assessed how the Transparent Reporting of Evaluations with Nonrandomized Designs (TREND) reporting guideline was used by authors and journal editors in journals' instructions to authors. We also evaluated its impact on reporting completeness and study quality. Methods. We extracted data from publications that cited TREND on how TREND was used in those reports; we also extracted information on journals' instructions to authors. We then undertook a case-control study of relevant publications to evaluate the impact of using TREND. Results. Between 2004 and 2013, TREND was cited 412 times, but it was only evidently applied to study reports 47 times. TREND was specifically mentioned 14 times in the sample of 61 instructions to authors. Some evidence suggested that use of TREND was associated with more comprehensive reporting and higher study quality ratings. Conclusions. TREND appeared to be underutilized by authors and journal editors despite its potential application and benefits. We found evidence that suggested that using TREND could contribute to more transparent and complete study reports. Even when authors reported using TREND, reporting completeness was still suboptimal.