In addition to challenges with enrollment, it was also difficult to keep participants retained and engaged at all phases of the study. Several individuals consented to participate but never made it to their first clinic visit. While our monthly clinic visits only lasted about 15 minutes, our clinics are held on weekdays from 8am-5pm, which posed challenges for those with less freedom to take time off work. We offered mail-in test kits to attempt to address this issue, but many participants still had difficulties making time for the study.
An unanticipated challenge in recruiting participants involved cultural considerations. Several households offered their contact information out of what we now perceive as courtesy or politeness but then were difficult to reach to complete the enrollment process. As a result, we switched to enrolling participants while visiting their homes to reduce attrition. We also emphasized that the study was voluntary, and they were not obligated to give their contact information if uninterested. Enacting this new strategy resulted in consenting 11 participants on the spot.
Door-to-door successfully yielded participants that were younger, had a lower income, and were more diverse in terms of race and ethnicity in comparison to participants recruited through other methods (Table 1; Figure 1). This was expected because we targeted our door-to-door recruitment geographically to improve reach of persons with these demographics. It also resulted in similar enrollment yield compared with other methods (Figure 2), with 4.6% (n=23) of homes visited enrolling in the study. However, door-to-door efforts did not yield enough participants to significantly increase the size or overall diversity of our cohort by race, ethnicity, or age. We anticipated this difficulty with enrolling homes in the door-to-door recruitment stage since they had already declined to respond to mailings and phone calls.
Unfortunately, we also have seen the greatest rate of withdrawal among participants recruited with the door-to-door method compared to others. Many of these participants missed initial visits and study staff put in extra effort to confirm appointments with participants to ensure the best chance of adherence. As of November 2021, about 43% of door-to-door participants have withdrawn compared to 16% of participants recruited by phone and 17% of postcard/email participants. We expected this as many of the door-to-door participants are socio-economically disadvantaged and likely to face additional barriers to participation and retention in research, compared to participants from socio-economically advantaged groups (12). Some barriers identified in previous reviews include mistrust in research and the medical system, limited transportation, time and financial constraints, and family obligations (13,14).
Table 1. Demographics of Chatham County, NC COVID-19 Cohort participants (n=153), stratified by method of recruitment
|
Postcard or Email (n=81 enrolled participants)
|
Phone Call
(n=49)
|
Door to Door
(n=23)
|
All participants
(n=153)
|
|
White Non-Hispanic
n / total responses (%)
|
62/77 (80.5%)
|
38/43 (88.3%)
|
6/15 (40%)
|
106/135 (78.5%)
|
|
Median Years of Age
(Q1, Q3)
|
63 (51, 70)
|
60 (47, 67)
|
45 (35, 59)
|
61 (47, 68)
|
|
Income n (%)
less than $49,999
$50,000-$74,999
$75,000 or more
Missing
|
14
21
41
5
|
(17.3%)
(25.9%)
(50.6%)
(6.2%)
|
9
9
27
4
|
(18.4%)
(18.4%)
(55.1%)
(8.2%)
|
9
3
3
8
|
(39.1%)
(13.0%)
(13.0%)
(34.8%)
|
32
33
71
17
|
(20.9%)
(21.6%)
(46.4%)
(11.1%)
|
|
|
|
|
|
|
|
|
|
|
Table 1. All demographic information was collected prior to the participant’s first visit or sample collection via email or paper surveys for participants without email.