USING TEXT MESSAGING TO CONTACT DIFFICULT-TO-REACH STUDY PARTICIPANTS

Kharbanda et al.¹ recently discussed the potential use of text messaging for immunization reminders. In addition to investigating how text messaging could improve this and other health-related outcomes,² we recommend researchers consider using it for contacting study participants expected to be difficult to reach.

In our study “Safe Point,” we pilot-tested a program that trained secondary exchangers—methamphetamine injectors who frequent our syringe exchange program and regularly provide syringes to others—to be peer educators who delivered HIV risk reduction messages to methamphetamine-injecting recipients who do not regularly attend syringe exchange programs. Our evaluation involved baseline and 3-month follow-up interviews with recipients identified by secondary exchangers. Forty-eight (75%) of 64 recipients who were eligible completed a baseline interview. All of these participants reported having injected methamphetamine within the past 60 days. Their drug use and other characteristics suggested that they would be difficult to reach (Table 1).

TABLE 1.

Characteristics of Methamphetamine Injectors (n = 48) Who Completed a Baseline Interview, Overall and by Text Message Preference: Safe Point Study, Portland, OR, 2008–2009

		Participantsa Indicating They Were Reachable by Text Messaging
	Participantsa (n = 48), % or Median (Range)	Yes (n = 35), % or Median (Range)	No (n = 13), % or Median (Range)
Female	40	43	31
White	81	83	77
High school education or less	71	71	69
Monthly income ≤ $400	36	38	31
Live more than 1 place in past 60 d	48	49	46
Age, y	42 (20–61)	43 (21–61)	40 (20–57)

^aParticipants were methamphetamine injectors who did not regularly visit a syringe exchange program themselves but received syringes from others who did attend a syringe exchange program.

Text messaging was an important way to reach enrolled participants during the study. Thirty-five (73%) indicated text messaging was a way to reach them—these participants appeared similar to the others (Table 1). Generally, study staff first tried to reach participants by calling them, and then tried text messaging, if possible. Staff attempted to reach 15 (31%) of the 48 enrolled participants by text messaging, and 8 of them (53%) responded to the text. Text messaging was the only way for staff to contact 3 participants at at least 1 point during the study. Overall, 43 (90%) of the 48 enrolled participants completed 3-month follow-up interviews. Five were not interviewed at follow-up: 3 were incarcerated, we had safety concerns in regard to 1 participant, and we were unable to reach the fifth participant.

Based on staff reports, participants who were reached by text messaging found it acceptable. Indeed, some seemed to prefer it, possibly because text messaging requires less of a time commitment, can be more private when others are present, and can feel less personal. Text messages also seemed easier to retrieve than did voice mail, and participants who responded to text messages did so within a day but often responded to phone messages less quickly. Last, study staff kept text messages sent to participants generic to maintain confidentiality (e.g., “Please contact Susie at [phone number]”), and participants did not report confidentiality concerns.

Text messaging was an acceptable means of communication for study participants and much cheaper than in-person field visits to participants. Given our success with text messaging and its extensive use,³ we recommend other studies consider using it as part of their comprehensive tracking protocol⁴ for contacting populations expected to be difficult to reach.