Comparison of characteristics and outcomes by initial study contact (website versus staff) for participants enrolled in a weight management study

Characterizing participants who respond to text, email, phone calls, or postcards in a SARS-CoV-2 prevalence study

INTRODUCTION

Multiple modalities and frequencies of contact are needed to maximize recruitment in many public health surveys. The purpose of this analysis is to characterize respondents to a statewide SARS-CoV-2 testing study whose participation followed either postcard, phone outreach or electronic means of invitation. In addition, we examine how participant characteristics differ based upon the number of contacts needed to elicit participation.

METHODS

This is a cross-sectional analysis of survey data collected from participants who were randomly selected to represent Indiana residents and were invited to be tested for Covid-19 in April 2020. Participants received invitations via postcard, text/emails, and/or robocalls/texts based upon available contact information. The modality, and frequency of contacts, that prompted participation was determined by when the notification was sent and when the participant responded and subsequently registered to participate in the study. Chi square analyses were used to determine differences between groups and significant findings were analyzed using multinomial logistic regression.

RESULTS

Respondents included 3,658 individuals and were stratified by postcards (7.9%), text/emails (26.5%), and robocalls/text (65.7%) with 19.7% registering after 1 contact, 47.9% after 2 contacts, and 32.4% after 3 contacts encouraging participation. Females made up 54.6% of the sample and responded at a higher rate for postcards (8.2% vs. 7.5%) and text/emails (28.1 vs. 24.6%) as compared to males (χ2 = 7.43, p = 0.025). Compared to males, females responded at a higher percentage after 1 contact (21.4 vs. 17.9%, χ2 = 7.6, p = 0.023). Those over 60 years responded most often after 2 contacts (χ2 = 27.5, p < 0.001) when compared to others at younger age groups. In regression analysis, participant sex (p = 0.036) age (p = 0.005), educational attainment (p = < 0.0001), and being motivated by "free testing" (p = 0.036) were correlated with participation in the prevalence study.

DISCUSSION

Researchers should be aware that the modality of contact as well as the number of prompts used could influence differential participation in public health studies. Our findings can inform researchers developing studies that rely on selective participation by study subjects. We explore how to increase participation within targeted demographic groups using specific modalities and examining frequency of contact.

Digital tools for the recruitment and retention of participants in randomised controlled trials: a systematic map

BACKGROUND

Recruiting and retaining participants in randomised controlled trials (RCTs) is challenging. Digital tools, such as social media, data mining, email or text-messaging, could improve recruitment or retention, but an overview of this research area is lacking. We aimed to systematically map the characteristics of digital recruitment and retention tools for RCTs, and the features of the comparative studies that have evaluated the effectiveness of these tools during the past 10 years.

METHODS

We searched Medline, Embase, other databases, the Internet, and relevant web sites in July 2018 to identify comparative studies of digital tools for recruiting and/or retaining participants in health RCTs. Two reviewers independently screened references against protocol-specified eligibility criteria. Included studies were coded by one reviewer with 20% checked by a second reviewer, using pre-defined keywords to describe characteristics of the studies, populations and digital tools evaluated.

RESULTS

We identified 9163 potentially relevant references, of which 104 articles reporting 105 comparative studies were included in the systematic map. The number of published studies on digital tools has doubled in the past decade, but most studies evaluated digital tools for recruitment rather than retention. The key health areas investigated were health promotion, cancers, circulatory system diseases and mental health. Few studies focussed on minority or under-served populations, and most studies were observational. The most frequently-studied digital tools were social media, Internet sites, email and tv/radio for recruitment; and email and text-messaging for retention. One quarter of the studies measured efficiency (cost per recruited or retained participant) but few studies have evaluated people's attitudes towards the use of digital tools.

CONCLUSIONS

This systematic map highlights a number of evidence gaps and may help stakeholders to identify and prioritise further research needs. In particular, there is a need for rigorous research on the efficiency of the digital tools and their impact on RCT participants and investigators, perhaps as studies-within-a-trial (SWAT) research. There is also a need for research into how digital tools may improve participant retention in RCTs which is currently underrepresented relative to recruitment research.

REGISTRATION

Not registered; based on a pre-specified protocol, peer-reviewed by the project's Advisory Board.

Impact of Baseline Assessment Modality on Enrollment and Retention in a Facebook Smoking Cessation Study

Background

Few studies have addressed enrollment and retention methods in online smoking cessation interventions. Fully automated Web-based trials can yield large numbers of participants rapidly but suffer from high rates of attrition. Personal contact with participants can increase recruitment of smokers into cessation trials and improve participant retention.

Objective

To compare the impact of Web-based (WEB) and phone (PH) baseline assessments on enrollment and retention metrics in the context of a Facebook smoking cessation study.

Methods

Participants were recruited via Facebook and Google ads which were randomly displayed to adult smokers in the United States over 27 days from August to September 2013. On each platform, two identical ads were randomly displayed to users who fit the advertising parameters. Clicking on one of the ads resulted in randomization to WEB, and clicking on the other ad resulted in randomization to PH. Following online eligibility screening and informed consent, participants in the WEB arm completed the baseline survey online whereas PH participants completed the baseline survey by phone with a research assistant. All participants were contacted at 30 days to complete a follow-up survey that assessed use of the cessation intervention and smoking outcomes. Participants were paid $15 for follow-up survey completion.

Results

A total of 4445 people clicked on the WEB ad and 4001 clicked on the PH ad: 12.04% (n=535) of WEB participants and 8.30% (n=332) of PH participants accepted the online study invitation (P<.001). Among the 726 participants who completed online eligibility screening, an equivalent proportion in both arms was eligible and an equivalent proportion of the eligible participants in both arms provided informed consent. There was significant drop-off between consent and completion of the baseline survey in the PH arm, resulting in enrollment rates of 32.7% (35/107) for the PH arm and 67.9% (114/168) for the WEB arm (P<.001). The overall enrollment rate among everyone who clicked on a study ad was 2%. There were no between group differences in the proportion that installed the Facebook app (66/114, 57.9% WEB vs 17/35, 49% PH) or that completed the 30-day follow-up survey (49/114, 43.0% WEB vs 16/35, 46% PH). A total of $6074 was spent on ads, generating 3,834,289 impressions and resulting in 8446 clicks (average cost $0.72 per click). Per participant enrollment costs for advertising alone were $27 WEB and $87 PH.

Conclusions

A more intensive phone baseline assessment protocol yielded a lower rate of enrollment, equivalent follow-up rates, and higher enrollment costs compared to a Web-based assessment protocol. Future research should focus on honing mixed-mode assessment protocols to further optimize enrollment and retention.

Assessment of response consistency and respective participant profiles in the Internet-based NutriNet-Santé Cohort

Whereas the feasibility and effectiveness of Internet-based epidemiologic research have been established, methodological support for the quality of such data is still accumulating. We aimed to identify sociodemographic differences among members of a French cohort according to willingness to provide part of one's 15-digit national identification number (personal Social Security number (PSSN)) and to assess response consistency based on information reported on the sociodemographic questionnaire and that reflected in the PSSN. We studied 100,118 persons enrolled in an Internet-based prospective cohort study, the NutriNet-Santé Study, between 2009 and 2013. Persons aged 18 years or more who resided in France and had Internet access were eligible for enrollment. The sociodemographic profiles of participants with discordant data were compared against those of participants with concordant data via 2-sided polytomous logistic regression. In total, 84,442 participants (84.3%) provided the first 7 digits of their PSSN, and among them 5,141 (6.1%) had discordant data. Our multivariate analysis revealed differences by sex, age, education, and employment as regards response consistency patterns. The results support the quality of sociodemographic data obtained online from a large and diverse volunteer sample. The quantitative description of participant profiles according to response consistency patterns could inform future methodological work in e-epidemiology.