Spinelli MA, et al. - Researchers conducted secondary data analysis of a large, prospective multi-site US PrEP demonstration project to investigate if measures of short-term and long-term PrEP adherence could be related to future study nonretention using an adjusted Cox-proportional hazards model. Within the US PrEP demonstration project, 294 individuals (median age 33 years) contributed drug levels, used to assess adherence. Observations revealed a strong association of both short- and long-term metrics of PrEP adherence with the future loss to follow-up in a US demonstration project study. They noted utility of short-term metrics of adherence, once available at the point-of-care, to direct real-time tailored retention and adherence interventions.