The trustworthiness of registered randomised control trials on hysteroscopy

The objective of this study was to assess the publication status of RCTs studying hysteroscopy registered on clinical trial registries, and the trustworthiness of these studies.

We systematically searched 23 clinical trial registries and MEDLine for studies on hysteroscopy registered between March 2012 and 25 March 2022. Published RCTs were assessed for trustworthiness using the Trustworthiness in RAndomised Controlled Trials (TRACT) checklist. Authors of studies with an unknown outcome were contacted.

In total, 576 registered and/or published RCTs were identified. We excluded 13 studies not reported in English, 100 studies which were not RCTs, 118 that did not investigate hysteroscopy, 8 studies that were terminated or withdrawn, 2 that were retracted, 64 studies that were ongoing, 5 conference abstracts and 96 studies with an unknown outcome. We therefore assessed 170 published articles for trustworthiness. The most prolific countries were China (n = 26), Egypt (n = 24), Turkey (n = 14) and Iran (n = 13), which were responsible for 45 % of studies. The average trustworthiness score across all 170 papers was 1.9 out of 7 with a range of 0-5 (higher values indicating more concerns regarding trustworthiness). Areas with highest concern for trustworthiness were zero dropout (n = 90, 53 %) and having exactly the same number of participants in each group (n = 75, 44 %). Other significant areas of concern were studies having absent (n = 42, 25 %) or retrospective registration (n = 24, 14 %) and authors or institutions with retracted papers or large numbers of RCTs in a short period (n = 28, 16 %). There were 46 studies (27 %) with concerns regarding trustworthiness across three different domains, 12 studies (7 %) with concerns across four domains and 3 studies (1.7 %) with concerns across five domains.

In research on hysteroscopy, many registered trials do not get published, in most cases for an unknown reason. A small number of countries are responsible for the majority of published hysteroscopy RCTs and registered trials with an unknown outcome. There is concern about the trustworthiness of RCTs published on hysteroscopy, with domains such as drop-out of participants, reporting participant characteristics and retrospective registration being areas for future methodological research.