Dataset Information

PrEP Adherence Patterns Strongly Affect Individual HIV Risk and Observed Efficacy in Randomized Clinical Trials.

ABSTRACT: BACKGROUND:Randomized controlled trials (RCTs) suggest that the efficacy of tenofovir-based preexposure prophylaxis (PrEP) strongly depends on the consistency of PrEP use. We explore how the patterns of pill taking and waning of PrEP protection may affect PrEP efficacy for HIV prevention. METHODS:A 2-arm RCT was simulated by mathematical models assuming that the prescribed daily doses were skipped periodically, randomly, or in large blocks. Risk-driven adherence, in which PrEP was taken when sex was expected, was also investigated. Three temporal PrEP protection profiles were explored: long (5 days), intermediate (3 days), and short (24 hours). Modeling results were compared to the efficacy observed in completed RCTs. RESULTS:The expected PrEP efficacy was 60% with periodic, 50% with random, and 34% with block adherence when PrEP had a long protection profile and pills were taken only 50% of the days. Risk-driven pill taking resulted in 29% and 37% daily pills taken and efficacy of 43% and 51%, respectively, for long protection. High PrEP efficacy comparable with that observed in Partners PrEP and Centers for Disease Control and Prevention Botswana trials was simulated under long protection, high overall adherence, and limited block pill taking; the moderate efficacy observed in iPrEx and Bangkok trials was comparable with the 50% adherence scenarios under random pill taking and long protection. CONCLUSIONS:Pill-taking patterns may have a substantial impact on the protection provided by PrEP even when the same numbers of pills are taken. When PrEP retains protection for longer than a day, pill-taking patterns can explain a broad range of efficacies observed in PrEP RCTs.

SUBMITTER: Dimitrov DT

PROVIDER: S-EPMC4925182 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

PrEP Adherence Patterns Strongly Affect Individual HIV Risk and Observed Efficacy in Randomized Clinical Trials.

Dimitrov Dobromir T DT Mâsse Benoît R BR Donnell Deborah D

Journal of acquired immune deficiency syndromes (1999) 20160801 4

<h4>Background</h4>Randomized controlled trials (RCTs) suggest that the efficacy of tenofovir-based preexposure prophylaxis (PrEP) strongly depends on the consistency of PrEP use. We explore how the patterns of pill taking and waning of PrEP protection may affect PrEP efficacy for HIV prevention.<h4>Methods</h4>A 2-arm RCT was simulated by mathematical models assuming that the prescribed daily doses were skipped periodically, randomly, or in large blocks. Risk-driven adherence, in which PrEP was ...[more]

PMID: 26990823

Similar Datasets

Project description:Climate change is arguably a major threat to biodiversity conservation and there are several methods to assess its impacts on species potential distribution. Yet the extent to which different approaches on species distribution modeling affect species richness patterns at biogeographical scale is however unaddressed in literature. In this paper, we verified if the expected responses to climate change in biogeographical scale-patterns of species richness and species vulnerability to climate change-are affected by the inputs used to model and project species distribution.We modeled the distribution of 288 vertebrate species (amphibians, birds and mammals), all endemic to the Amazon basin, using different combinations of the following inputs known to affect the outcome of species distribution models (SDMs): 1) biological data type, 2) modeling methods, 3) greenhouse gas emission scenarios and 4) climate forecasts. We calculated uncertainty with a hierarchical ANOVA in which those different inputs were considered factors.The greatest source of variation was the modeling method. Model performance interacted with data type and modeling method. Absolute values of variation on suitable climate area were not equal among predictions, but some biological patterns were still consistent. All models predicted losses on the area that is climatically suitable for species, especially for amphibians and primates. All models also indicated a current East-western gradient on endemic species richness, from the Andes foot downstream the Amazon river. Again, all models predicted future movements of species upwards the Andes mountains and overall species richness losses.From a methodological perspective, our work highlights that SDMs are a useful tool for assessing impacts of climate change on biodiversity. Uncertainty exists but biological patterns are still evident at large spatial scales. As modeling methods are the greatest source of variation, choosing the appropriate statistics according to the study objective is also essential for estimating the impacts of climate change on species distribution. Yet from a conservation perspective, we show that Amazon endemic fauna is potentially vulnerable to climate change, due to expected reductions on suitable climate area. Climate-driven faunal movements are predicted towards the Andes mountains, which might work as climate refugia for migrating species.

Dataset Information

PrEP Adherence Patterns Strongly Affect Individual HIV Risk and Observed Efficacy in Randomized Clinical Trials.

Publications

PrEP Adherence Patterns Strongly Affect Individual HIV Risk and Observed Efficacy in Randomized Clinical Trials.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets