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

INTRODUCTION: Electronic search filters on family medicine or general practice studies have been developed and validated in previous work. However, there has been 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 the 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 the funding source. Two registries - International Standard Randomised Controlled Trials Number Registry (245 (42.9%)) and ClinicalTrials.gov (209 (36.6%)) - 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%) articles. CONCLUSION: A compilation of published RCT protocols on PHC was feasible. The majority of protocols on PHC were published over the past 10 years, funded by the government and designed in three main countries.

Underreporting contextual factors preclude the applicability appraisal in primary care randomized controlled trials.

OBJECTIVES: To assess applicability reporting in randomized controlled trials (RCTs) conducted in primary care (PC). STUDY DESIGN AND SETTING: We used a random sample of PC RCTs published between 2000 and 2020 to assess applicability. We extracted data related to setting, population, intervention (including implementation), comparator, outcomes, and context. Based on data availability, we assessed whether the five predefined applicability questions were adequately addressed by each PC RCT. RESULTS: Adequately described elements that were reported frequently (>50%) included the responsible organization for intervention provision (97, 93.3%), study population characteristics (94, 90.4%), intervention implementation including monitoring and evaluation (92, 88.5%), intervention components (89, 85.6%), time frame (82, 78.8%), baseline prevalence (58, 55.8%), and the type of setting and location (53, 51%). Elements that were often underreported included contextual factors, that is, evidence of differential effects across sociodemographic or other groupings (2, 1.9%), intervention components tailored for specific settings (7, 6.7%), health system structure (32, 30.8%), factors affecting implementation (40, 38.5%) and organization structure (50, 48.1%). The proportion of trials that adequately addressed each applicability question ranged between 1% and 20.2%, while none RCT could address all of them. CONCLUSION: Underreporting contextual factors jeopardize the appraisal of applicability in PC RCTs.

Proportion of published primary health care protocols with published results in subsequent papers was decreasing.

OBJECTIVES: We assessed the proportion of primary health care (PHC) randomized controlled trial (RCT) protocols published in peer-reviewed journals that published results in subsequent papers in peer-reviewed journals; and whether this proportion changed over time. STUDY DESIGN AND SETTING: We searched (last update June 2019) for RCTs published in peer-reviewed journals reporting primary outcome results for 620 protocols that were published up to 2014 and were retrieved in PubMed. We recorded the absolute number and the proportion of protocols with published results per year; and estimated whether the proportion changed over time. RESULTS: Of the 620 published protocols, 525 (85%) disseminated their results through a published RCT by June 2019. The number of published protocols was increasing over time especially after 2001. However, the proportion of protocols per year with published results in subsequent papers was decreasing over time after 2002. Specifically, the proportion ranged from 86% to 96% for protocols published until 2010 while for those published from 2011 onward ranged from 76% to 86%. Mean time from protocol to results publication was 39 months (95% CI 37, 41). CONCLUSION: Almost one-sixth of PHC trial protocols published in peer-reviewed journals did not publish their results in subsequent papers.