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Using social media to recruit study participants for a randomised trial for hypertension (Preprint)


 BACKGROUND
 Great and costly efforts are required to recruit potential participants into clinical trials. Using social media may make the recruitment process more efficient. Merely 20% of clinical trials are completed on time, a finding mostly linked to challenges in patient recruitment [1]. Recruitment through social media is increasingly being recognized as a tool to efficiently identify eligible subjects at lower costs [2, 3]. One of the key reasons for its success is the strong adherence of users to specific social media platforms. Facebook for instance has over 2.38 billion active monthly users of which about 75% access the network on a daily basis [4]. As such, the platform and other like it offer great potential to quickly and affordably enroll patients into clinical trials and surveys [3, 5-7].
At present, little evidence is available on the efficacy of using social media to recruit patients into cardiovascular and hypertension trials [8]. The aim of the present study was to evaluate the efficacy of social media as an approach to recruit hypertensive patients into the RADIANCE-HTN SOLO trial.
 
 
 OBJECTIVE
 The aim of the present study was to evaluate the efficacy of social media as an approach to recruit hypertensive patients into the RADIANCE-HTN SOLO trial.
 
 
 METHODS
 The RADIANCE-HTN SOLO (NCT02649426) is a multicenter, randomised study that was designed to demonstrate the efficacy and safety of endovascular ultrasound renal denervation (RDN) to reduce ambulatory blood pressure at 2 months in patients with combined systolic–diastolic hypertension in the absence of medications. 
Between March 28, 2016, and Dec 28, 2017, 803 patients were screened for eligibility and 146 were randomised to undergo RDN (n=74) or a sham procedure (n=72) [9]. Key entry criteria included: age 18-75 years with essential hypertension using 0-2 antihypertensive drugs. Patients were recruited from 21 hospitals in the USA and 18 hospitals in Europe. 
The study was approved by local ethics committees or institutional review boards and was performed in accordance with the declaration of Helsinki. All participants provided written informed consent. All recruitment materials including social media campaigns was approved by local ethics committees of the involved sites. 
Recruitment strategies included social media (Facebook), conventional advertisements (ads) (magazine, brochure/poster, radio, newspaper), web search (the clinical website, craigslist and web-browsing), and physician referral. 
Both newspaper ads and posters contained brief information about study entry criteria. Newspapers were distributed at public transport places and posters were displayed in outpatient cardiology and hypertension clinics. 
Radio ads were run for 30 or 60 seconds providing a short summary of the study, entry criteria and contact information. Ads were run in major metropolitan areas on radio stations with large adult listener bases during popular days and times.
Facebook ads were targeted towards subjects >45 years old within a certain distance from a recruitment site (range 20-50 miles). Criteria were modified over time in order to increase response rates [i.e. distance was increased or decreased, age was increased to >55 year]. Facebook ads referred to a dedicated study website translated into country specific languages. If interested, subjects could complete an anonymous online screening questionnaire which provided direct automatic feedback on study eligibility. Eligible subjects were asked to provide contact details (name and telephone number) to receive additional information, a process coordinated via a secure online portal (Galen Gateway Patient Recruitment Portal, Galen Patient Recruitment, Inc., Cumberland, RI). Study site were only able to contact potential candidates within their area. The study sponsor was not able to access any personal data. 
Trained local site personnel or contracted secondary screeners contacted candidates by phone to verify eligibility and answer potential questions. A subsequent outpatient clinic visit was scheduled during which the study was explained in greater detail and the informed consent form could be signed. 

Statistical analysis
Categorical variables were expressed as percentages and counts. Continuous variables were described as mean  standard deviation (SD) when normally distributed, data was compared using an Independent-Samples or Paired-Samples T test to analyze the difference between recruitment methods. In case of non-normal distribution, median data was presented with the interquartile range [IQR]. All statistical tests are 2-tailed. A P-value <0.05 was considered statistically significant. Statistical analysis was performed using SPSS statistical analysis (version 24.0). 
 
 
 
 RESULTS
 Results
Facebook ads were active during a 115-day recruitment period between August and November 2017. A total of 285 potential candidates were recruited by different recruitment strategies in this specific time period, of which 184 (65%) were consented through Facebook (Table 1).
The average age of the subjects consented through Facebook was 59 ± 8 years and 51% were male (Table 2).
Facebook reached 5.3 million people in 168 separate campaigns run in proximity to 19 sites in the US and 14 sites in Europe. The number of candidates per site was variable with a median of 23 [17 – 26] candidates per site that passed the questionnaire (Figure 1). A total of 27/184 subjects were eventually randomised. 
Total cost for the Facebook ads was $152,412; costing $907/campaign and $0.83/click. This resulted in a total cost of $828/consent. 
During the same recruitment period, 7-day radio spots were launched with a total cost of $2,870; resulting in 9 inquiries with eventually 5 potential candidates and 2 consents ($1,435/consent). 
 
 
 
 CONCLUSIONS
 Conclusion
Targeted social media was a successful and efficient strategy to find potential candidates for a multicenter blood pressure clinical trial. Whether this approach can be replicated across other disease states or demographics remains to be studied.
