Trials with proxy-reported outcomes registered on the Australian New Zealand Clinical Trials Registry (ANZCTR)
A proxy is someone other than a patient who reports a patient’s outcomes as if they are the patient. Due to known discordance with patient reports, proxies are often not recommended in clinical trials; however, proxies may be needed in certain research contexts. We aimed to identify and describe trials registered on the Australian New Zealand Clinical Trials Registry (ANZCTR) with proxy-reported endpoints.
ANZCTR was systematically searched from inception (2005) to 31 March 2017 for trials with proxy-reported endpoints. Primary and secondary endpoints for each trial retrieved by the search were individually coded (proxy-reported: yes/no), and trials with confirmed proxy-reported endpoints were included in the analysis.
Of 13,666 registered trials, 469 (3.4%) included a proxy-reported endpoint (867 individual proxy-reported endpoints in total: 62% family member proxy, 22% health professional). Proxy endpoint inclusion did not significantly increase over time (r = 0.18, p = 0.59). Mental health (11.5%), stroke (10.3%) and neurological (8.3%) trials had the highest proportion of trials using proxies. Of the 469 trials, 123 (26.2%) studies involved paediatric patients.
Proxy-reported endpoints are included in a small but notable number of studies, which may indicate other types of outcomes are used for patients unable to self-report, or that these patients are under-researched.
KeywordsProxy-reported outcomes Quality of life Clinical trial registration Clinical trial endpoint Outcome measures
We acknowledge ANZCTR for providing access to the study data, and thank Kylie Hunter (ANZCTR) for in-kind support, Ailsa Langford and Thuyen Vu (ANZCTR) for assistance with the search strategy and data retrieval. We also thank Elizabeth Vodicka, Beth Devine and colleagues for sharing the search terms used in the review of clinicaltrials.gov.
Compliance with ethical standards
Conflict of interest
The authors declare no conflicts of interest.
The University of Sydney Human Research Ethics Committee does not review studies that do not include human participants and therefore human research ethics approval was not required for this study.
We obtained permission from the ANZCTR to conduct this research. No human research participants were involved in this study, therefore informed consent was not required.
Research involving human and animal participants
In accordance with the University of Sydney’s (sponsor) ethical procedures, this research did not include human research participants and therefore human research ethics approval was not required. The data included in this study are publically available on ANZCTR and concerns clinical trial information. No human data were included in this analysis.
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