Procedures
Participants were recruited from the Mombasa Cohort, a long-term open cohort study of women who self-identified as having exchanged sex for goods or money in the past month at the time of enrollment. Participants in the Mombasa Cohort attended monthly follow-up appointments with regular HIV and STI screening. Detailed methods have been described elsewhere [Eligible women were offered enrollment after completing written informed consent for participation in the trial. A face-to-face interview was conducted using a standardized questionnaire to collect information on demographic characteristics, medical history, and sexual behavior. Participants received a second pre-ART counseling session that highlighted the importance ART adherence and discussed barriers and facilitators. A one-month supply of ART was dispensed, and participants were randomized to the intervention and control conditions.The randomization was generated by a biostatistician who had no other role in the study. Participants were assigned to the intervention or control arm in a 1:1 ratio using block randomization with variable block sizes. In Mombasa, treatment groups were assigned using sealed, opaque, serially numbered envelopes ordered in the sequence of treatment assignments generated using STATA version 14 (StataCorp, College Station, TX, USA). Due to the nature of the intervention, neither participants nor study staff could be blinded to study arm assignment. Differences in clinical management and counselling were minimized by providing pre-ART counseling prior to randomization and adhering to comprehensive standard operating procedures that guided participant counseling and evaluations during follow-up.With the exception of informed consent forms, hard copies of data collection forms and electronic files did not include personal identifiers. All study documents were maintained in locked cabinets within filing rooms accessible only to study staff, and consents were stored separately from other study documents. Electronic data files were encrypted, password protected and accessible only to the research team.Following the enrollment visit, all participants were asked to return monthly for six months. At each visit, study staff assessed ART adherence, discussed adherence barriers, and provided ART refills. Adherence data were collected monthly using a self-reported, validated visual analogue scale (VAS) [Participants randomized to the control arm received standard of care for ART delivery according to Kenyan guidelines. Consistent with the standard of care for ART delivery in the research clinic, participants in the control arm were provided with a phone number to contact a nurse or doctor if they had questions.In addition to all services provided in the control condition, participants randomized to the intervention arm received the mHealth intervention, During the exit interview six months following treatment initiation, we assessed the intervention’s acceptability. Women in the intervention arm were asked to share their reactions to the intervention and suggestions for improvement. Specifically, feedback was elicited about the intervention’s content, structure (including the number and frequency of messages), and confidentiality concerns.Results were disseminated to participants and stakeholders through a Community Advisory Board and multiple dissemination meetings targeting different groups including participants, collaborating institutions, and health department officials at the local and national level.