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BACKGROUND:Objective adherence metrics for tenofovir (TFV) disoproxil fumarate/emtricitabine(FTC)-based PrEP were critical for interpretation of efficacy in PrEP clinical trials, and there is increasing interest in using drug levels to tailor interventions for reengagement and adherence. Point-of-care immunoassays (POC) for TFV, which examine short-term adherence, are in development. However the ability of poor short-term and long-term adherence to predict future PrEP non-retention is unknown. SETTING:Secondary data analysis of a large, prospective multi-site U.S. PrEP demonstration project METHODS:: An adjusted Cox-proportional hazards model examined the relationship of dried blood spot (DBS) levels of FTC-triphosphate (FTC-TP) or TFV-diphosphate (TFV-DP), measures of short-term and long-term PrEP adherence, respectively, with future study non-retention. RESULTS:Overall, 294 individuals (median age 33 years) contributed drug levels within the U.S. PrEP demonstration project. By study end, 27% were lost to follow-up, 25% had at least one undetectable FTC-TP level indicating poor short-term adherence, and 29% had a drug level indicating sub-optimal long-term adherence (TFV-DP

BackgroundHIV preexposure prophylaxis (PrEP) using daily oral tenofovir-disoproxil-fumarate/emtricitabine (TDF/FTC) is effective for preventing HIV acquisition, but concerns remain about its potential kidney toxicity. This study examined kidney function in individuals using PrEP in real-world clinical settings.SettingDemonstration project in 2 sexually transmitted infection clinics and a community health center.MethodsWe evaluated kidney function among men who have sex with men and transgender women taking tenofovir-disoproxil-fumarate/emtricitabine PrEP for up to 48 weeks. Serum creatinine and urine dipstick for protein were obtained at 12-week intervals. Kidney function was estimated using creatinine clearance (CrCl) (Cockcroft-Gault) and estimated glomerular filtration rate (eGFR) (CKD-EPI).ResultsFrom October 2012 to January 2014, we enrolled 557 participants (median age 33). Mean creatinine increased from baseline to week 12 by 0.03 mg/dL (4.6%) (P < 0.0001); mean CrCl decreased by 4.8 mL/min (3.0%) (P < 0.0001). These changes remained stable through week 48 (P = 0.81, P = 0.71 respectively). There were 75/478 (15.7%) participants who developed worsening proteinuria at week 12 compared with baseline (P < 0.0001), and this percent remained stable through week 48 (P = 0.73). Twenty-five participants (5.1%) developed new-onset eGFR

ObjectiveThe US preexposure prophylaxis (PrEP) Demonstration Project (U.S. Demo) evaluated MSM on PrEP postmarketing and found low seroconversion rates. The objective of this study is to examine hair levels as an adherence measure to PrEP.DesignUsing an 'opt-in' design, participants of PrEP Demo were invited to enroll into a substudy where hair was collected quarterly.MethodsTenofovir concentrations were measured in hair by liquid chromatography/tandem mass spectrometry. Hair levels consistent with ≥4 doses/week (protective in other studies) defined adequate adherence. Mixed effects multivariate logistic regression models examined factors associated with ≥4 doses/week. Separate mixed effects models evaluated the relationship between hair PrEP levels and changes in creatinine clearance (CrCl) over time.ResultsOverall, 58% of U.S. Demo participants enrolled into this opt-in study; reasons for nonparticipation included insufficient hair (61%) and concerns about hairstyle (27%). Hair and dried blood spots levels consistent with ≥4 doses/week were highly concordant (84%). Hair levels showed adequate adherence in 87% of 875 person-visits (among 280 participants). Factors associated with adequate adherence in multivariate models were amphetamine use [adjusted odds ratio (aOR) 2.59 (0.97-6.9, P 0.06)], condomless receptive anal sex [aOR 2.28 (1.19-4.40, P 0.01)], and stable housing [aOR 2.63 (1.03-6.67), P 0.04]. Hair levels of tenofovir showed a monotonic relationship with decline in CrCl (P 0.01 for trend).ConclusionIn this substudy of the U.S. PrEP demonstration project, hair and dried blood spots levels were highly concordant and hair concentrations demonstrated adequate adherence 87% of the time, with stable housing and high-risk behavior associated with higher adherence. Daily PrEP drug taking is associated with modest declines in CrCl.

ImportanceSeveral randomized clinical trials have demonstrated the efficacy of preexposure prophylaxis (PrEP) in preventing human immunodeficiency virus (HIV) acquisition. Little is known about adherence to the regimen, sexual practices, and overall effectiveness when PrEP is implemented in clinics that treat sexually transmitted infections (STIs) and community-based clinics serving men who have sex with men (MSM).ObjectiveTo assess PrEP adherence, sexual behaviors, and the incidence of STIs and HIV infection in a cohort of MSM and transgender women initiating PrEP in the United States.Design, setting, and participantsDemonstration project conducted from October 1, 2012, through February 10, 2015 (last date of follow-up), among 557 MSM and transgender women in 2 STI clinics in San Francisco, California, and Miami, Florida, and a community health center in Washington, DC. Data were analyzed from December 18, 2014, through August 8, 2015.InterventionsA combination of daily, oral tenofovir disoproxil fumarate and emtricitabine was provided free of charge for 48 weeks. All participants received HIV testing, brief client-centered counseling, and clinical monitoring.Main outcomes and measuresConcentrations of tenofovir diphosphate in dried blood spot samples, self-reported numbers of anal sex partners and episodes of condomless receptive anal sex, and incidence of STI and HIV acquisition.ResultsOverall, 557 participants initiated PrEP, and 437 of these (78.5%) were retained through 48 weeks. Based on the findings from the 294 participants who underwent measurement of tenofovir diphosphate levels, 80.0% to 85.6% had protective levels (consistent with ≥4 doses/wk) at follow-up visits. African American participants (56.8% of visits; P = .003) and those from the Miami site (65.1% of visits; P

INTRODUCTION Stroke and pulmonary embolism have devastating, often lifelong health consequences, and conditions that predispose to these events (atrial fibrillation, deep vein thrombosis, and mechanical heart valves) are common. Warfarin [...], PURPOSE Without supporting evidence, clinicians commonly recommend that warfarin be taken in the evening. We conducted a randomized controlled trial to evaluate the effect of administration time (morning vs evening) on the stability of warfarin&apos;s anticoagulant effect. METHODS A total of 236 primary care physicians serving 54 western Canadian communities mailed letters of invitation to all their warfarin-using patients. Eligible patients were community-dwelling warfarin users (any indication) with at least 3 months of evening warfarin use and no plans for discontinuation. Participants were randomized (by web-based allocation) to morning vs continued evening warfarin ingestion. We used the Rosendaal method to determine the proportion of time within therapeutic range (TTR) of the international normalized ratio (INR) blood test month 2 to 7 postrandomization vs the 6 months prerandomization. The primary outcome was the percent change in proportion of time outside target INR range (with an a priori minimum clinically important difference of [+ or -] 20%). All analyses were intention to treat. RESULTS Between March 8, 2015 and September 30, 2016, we randomized 109 participants to morning and 108 to evening warfarin use. TTR rose from 71.8% to 74.7% in the morning group, and from 72.6% to 75.6% in the evening group, for a change in TTR of 2.9% in the former vs 3.0% in the latter (difference, -0.1%; P = .97; 95% CI for the difference, -6.1% to 5.9%). The difference in percent change in proportion of time outside the therapeutic INR range (obtained via Hodges-Lehmann estimation of the difference in medians) was 4.4% (P = .62; 95% CI for the difference, -17.6% to 27.3%). CONCLUSIONS Administration time has no statistically significant nor clinically important impact on the stability of warfarin&apos;s anticoagulant effect. Patients should take warfarin whenever regular compliance would be easiest. Key words: chronotherapy; warfarin; Coumadin; TTR; anticoagulation; atrial fibrillation; thromboembolism; mechanical valve; primary care; practice-based research