Strategies for Good Retention Rates in HIV Exposed Sero-Negatives (HESN) Individuals: Important Consideration for HIV Biomedical Prevention Trials in Nigeria

Background: Retention in clinical trials is critical for the accumulation of data over time and retaining enough power for comprehensive analysis. We document for the first time the retention rates and factors associated with retention among a cohort of HIV exposed seronegative (HESN) person in a discordant relationship. Understanding these factors will provide valuable cues for maintaining high retention rates in future HIV biomedical prevention studies in this cohort. Aim: We aimed to document retention rates and associated factors relevant in conducting future HIV prevention studies using a cohort of HIV exposed sero-negative individuals. Method: We conducted a prospective cohort study to enroll HESN persons in discordant relationship based on established inclusion criteria that includes: Established sero-discordance with at least 3 months in the relationship; above 18 years and willingness to be followed up. Relevant ethical approvals were obtained. Following informed consent at enrollment, standardized questionnaires on risk behavior and factors that may affect retention were administered at enrollment and during the 2 years follow-up. This was spread over 10 follow-up visits to mimic phase a 2b HIV vaccine clinical trial follow up and duration. In addition, clinical examinations were done and samples collected for safety lab during the follow up visits. Estimation of CD4 and viral load was also done for the HIV+ partners of HESN study participants. Results: Six hundred and sixty HESN persons were screened and 534 (81%) enrolled (i.e. month 0) and followed up. There was a decline in retention from 96% at month 1 (visit 1) to 78% at month 24 (Visit 10). Sharpest drop out from the study occurred at month 1 (20%) and month 15 (14%) follow-up visits. Inability to reach study participants, unwillingness of study participants to continue study, and mortality of the HIV+ partners of HESN participants were the commonest reasons for participant study termination. Furthermore, no or low level of formal education, (AOR 2.79; 95% CI 1.29 - 6.02, p = 0.06), being unemployed (AOR 1.96; 95% CI 1.18 - 3.29, p < 0.01) and inconsistent use of condoms (AOR 1.83; 95% CI 1.16 - 2.91, p < 0.01) were predictors of non-completion of the study. Conclusion: Retention rates decline especially during month 1 (visit 1) and month 15 (visit 7) mainly due to participants’ inability to locate study participants and death of HIV+ partners of HESN enrollees. One unexpected finding from our study is that those who were more consistent in their use of condom were more likely to stay in the study. This is a possible indication of commitment or an incentive for giving free condoms at study visits. This is encouraging for combined biomedical prevention strategies where consistent condoms use is desired. On the other hand, factors such as unemployment, poor formal education and never/occasional condom use were predictors of study drop out. Retention strategies should consider these barriers and predictors of drop out as exclusion criteria in preparation for future HIV biomedical prevention trial.