The strongest predictor of dropout was a baseline level of self-reported depressive symptoms consistent with severe depression (10
). Given the higher likelihood of mortality and treatment non-adherence associated with depression (11
) and the higher rates of dropout found in this and other health-related programs (13
), early screening for depression in clinical trials is warranted and can provide opportunity for immediate treatment referral and follow-up. While good clinical research practices include maximizing retention in clinical trials, and exclusion of individuals with depression may help meet retention goals, in the absence of safety concerns, fairness considerations would suggest inclusion of such individuals because of the potential for benefit to the individuals in studies like this one. Moreover, inclusion of individuals with depression, to the extent to which they are present in the population of persons living with HIV/AIDS, increases generalizability findings. Thus, the benefit in terms of knowledge, protection and fair treatment of human participants would outweigh the potential advantages to research design.
That younger age was predictive of dropout is not surprising given the documented challenges of recruiting and retaining younger participants in research studies (13
). The link between ART receipt and better retention suggests that individuals receiving stable ongoing medical care may have less chaotic personal circumstances. It is also possible that routine medical appointments associated with ART delivery may facilitate adherence to ancillary services.
Dropout was unrelated to level of transmission risk at baseline and to randomization status. This finding provides evidence against the possible effects of selective dropout bias on primary risk study outcomes. If those who dropped out were at higher risk for transmitting HIV and this were related to randomization status (e.g., feeling discouraged by the demands of the intervention), there would be concerns regarding the trial outcomes. Instead, the current analyses provide evidence of the feasibility of retaining high-risk participants in behavioral intervention trials of public health significance.
Limitations of note in the current analyses include the use of a convenience, non-probability-based sample and the use of self-reported data for several key variables, including depression and substance use.
In summary, self-reported depressive symptoms, younger age, and non-receipt of antiretroviral therapy were predictive of attrition in a trial of high-risk HIV-infected men and women. Drug use and HIV transmission risk were unrelated to dropout, supporting the focus on high-risk individuals for risk-reduction interventions.