Original Research

Searching for published protocols of randomized controlled trials in primary health care: an empirical systematic approach


Evridiki Papagiannopoulou1 RN, PhD Candidate

Christina Antoniadou2 MD, Research Associate

Eleni Ntalaouti3 MD, Research Associate

Evangelia Ntzani4 MD, Associate Professor

Konstantinos Siamopoulos5 MD, Professor Emeritus

name here
Athina Tatsioni6
PhD, Associate Professor *


1, 2, 3, 6 Research Unit for General Medicine and Primary Health Care, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece

4 Department of Hygiene and Epidemiology, Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece; and Center for Evidence-Based Medicine, Department of Health Services, Policy and Practice, School of Public Health, Brown University, Providence, RI, USA

5 Faculty of Medicine, School of Health Sciences, University of Ioannina, Ioannina, Greece

ACCEPTED: 25 November 2019

early abstract:

Introduction: Previous articles have developed and validated electronic search filters on family medicine or general practice studies. However, there is no systematic effort to specifically identify and record protocols of randomized controlled trials (RCT) protocols in primary health care (PHC). The aim of the present study was to systematically identify published RCT protocols in PHC and capture information about specific protocol characteristics that may describe this field.

Methods: PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Scopus from inception to December 2014 were systematically searched.Protocols of RCTs that were published in English and were relevant to PHC were considered as eligible. Protocols referred either to a mixed population, or to an intervention including a specialized part as well as pilot or feasibility trial protocols were excluded. Specific protocol characteristics including publication year, country, prospective registration, funding, and publication sources were extracted.

Results: The final database included 628 published RCT protocols (median publication year 2011; interquartile range 2009, 2013). The majority of protocols were designed in UK (n=141, 22.5%), the Netherlands (n=105, 16.7%), and USA (n=93, 14.8%). Research was mainly funded by the government (n=408, 65.0%) while 45 protocols (7.2%) included industry as funding source. Two registries, i.e., 245 (42.9%) in ISRCTN Registry, and 209 (36.6%) in ClinicalTrials.gov, indexed most of the protocols. Journals from several scientific fields published the articles; the field of “Primary Health Care Medicine, General and Internal” included 69 (11.0%) papers.

Conclusions: A compilation of published RCT protocols on PHC was feasible.  The majority of protocols on PHC was published during the last decade, funded by the government and designed in three main countries.