Bone Mineral Density Changes Among Young, Healthy African Women Receiving Oral Tenofovir for HIV Preexposure Prophylaxis

The effect of daily oral PrEP use during pregnancy on bone mineral density among adolescent girls and young women in Uganda

Introduction

Oral pre-exposure prophylaxis (PrEP) is recommended during pregnancy for at-risk cisgender women. Pregnancy is known to impede bone growth and tenofovir-based PrEP may also yield detrimental changes to bone health. Thus, we evaluated the effect of PrEP use during pregnancy on bone mineral density (BMD).

Methods

We used data from a cohort of women who were sexually active, HIV-negative, ages 16-25 years, initiating DMPA or choosing condoms for contraception and enrolled in the Kampala Women's Bone Study. Women were followed quarterly with rapid testing for HIV and pregnancy, PrEP dispensation, and adherence counseling. Those who became pregnant were counseled on PrEP use during pregnancy per national guidelines. BMD of the neck of the hip, total hip, and lumbar spine was measured using dual-energy x-ray absorptiometry at baseline and annually. We compared the mean percent change in BMD from baseline to month 24.

Results

Among 499 women enrolled in the study, 105 pregnancies occurred in 90 women. At enrollment, the median age was 20 years (IQR: 19-21) and 89% initiated PrEP. During pregnancy, 67% of women continued using PrEP and PrEP was dispensed in 64% of visits. BMD declined significantly in women using PrEP during pregnancy compared to women who were not pregnant nor used PrEP: relative BMD change was -2.26% (95% CI: -4.63 to 0.11, p = 0.06) in the femoral neck, -2.57% (95% CI: -4.48 to -0.66, p = 0.01) in total hip, -3.06% (95% CI: -5.49 to -0.63, p = 0.001) lumbar spine. There was no significant difference in BMD loss when comparing PrEP-exposed pregnant women to pregnant women who never used PrEP. Women who became pregnant were less likely to continue PrEP at subsequent study visits than women who did not become pregnant (adjOR: 0.25, 95% CI: 0.16-0.37, p < 0.001). Based on pill counts, there was a 62% reduction in the odds of high PrEP adherence during pregnancy (adjOR = 0.38, 95% CI: 0.27-0.58, p < 0.001).

Conclusion

Women who used PrEP during pregnancy experienced a similar reduction in BMD as pregnant women with no PrEP exposure, indicating that BMD loss in PrEP-using pregnant women is largely driven by pregnancy and not PrEP.

Preexposure Prophylaxis for the Prevention of HIV: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

Importance

A 2019 review for the US Preventive Services Task Force (USPSTF) found oral preexposure prophylaxis (PrEP) associated with decreased HIV infection risk vs placebo or no PrEP in adults at increased HIV acquisition risk. Newer PrEP regimens are available.

Objective

To update the 2019 review on PrEP, to inform the USPSTF.

Data Sources

Ovid MEDLINE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and Embase (January 2018 to May 16, 2022); surveillance through March 24, 2023.

Study Selection

Randomized clinical trials of PrEP vs placebo or no PrEP or newer vs older PrEP regimens and diagnostic accuracy studies of instruments for predicting incident HIV infection.

Data Extraction and Synthesis

Dual review of titles and abstracts, full-text articles, study quality, and data abstraction. Data were pooled using the DerSimonian and Laird random-effects model.

Main Outcomes and Measures

HIV acquisition, mortality, and harms; and diagnostic test accuracy.

Results

Thirty-two studies were included in the review (20 randomized clinical trials [N = 36 543] and 12 studies of diagnostic accuracy [N = 5 544 500]). Eleven trials in the 2019 review found oral PrEP associated with decreased HIV infection risk vs placebo or no PrEP (n = 18 172; relative risk [RR], 0.46 [95% CI, 0.33-0.66]). Higher adherence was associated with greater efficacy. One new trial (n = 5335) found oral tenofovir alafenamide/emtricitabine (TAF/FTC) to be noninferior to tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) in men who have sex with men (RR, 0.47 [95% CI, 0.19-1.14]). Two new trials found long-acting injectable cabotegravir associated with decreased risk of HIV infection vs oral TDF/FTC (RR, 0.33 [95% CI, 0.18-0.62] in cisgender men who have sex with men and transgender women [n = 4490] and RR, 0.11 [95% CI, 0.04-0.31] in cisgender women [n = 3178]). Discrimination of instruments for predicting incident HIV infection was moderate in men who have sex with men (5 studies; n = 25 488) and moderate to high in general populations of persons without HIV (2 studies; n = 5 477 291).

Conclusions and Relevance

In adults at increased HIV acquisition risk, oral PrEP was associated with decreased risk of acquiring HIV infection compared with placebo or no PrEP. Oral TAF/FTC was noninferior to oral TDF/FTC, and injectable cabotegravir reduced the risk of HIV infection compared with oral TDF/FTC in the populations studied.

Bone changes with candidate PrEP regimens containing tenofovir disoproxil fumarate and/or maraviroc and/or emtricitabine in US men and women: HPTN 069/ACTG A5305

BACKGROUND

Tenofovir disoproxil fumarate-containing pre-exposure prophylaxis (PrEP) has been associated with decreases in bone mineral density (BMD), but the bone effects of other non-tenofovir disoproxil fumarate candidate PrEP regimens are not well described.

METHODS

The HPTN 069/ACTG A5305 study randomized 406 US cisgender men and transgender women, and 188 cisgender women at risk for HIV infection to one of four double-blinded regimens: (i) maraviroc; (ii) maraviroc + emtricitabine; (iii) maraviroc + tenofovir disoproxil fumarate; or (iv) tenofovir disoproxil fumarate + emtricitabine. BMD was measured in a subset of participants at the lumbar spine (LS) and hip by dual-energy X-ray absorptiometry (DXA) at baseline and 48 weeks. Percentage change in LS and hip BMD was compared between the tenofovir disoproxil fumarate- and non-tenofovir disoproxil fumarate-containing arms by Wilcoxon rank-sum tests and multiple linear regression adjusting for sex, race and baseline BMI.

RESULTS

At baseline (n = 307), the median age was 33 years, 56% male and 43% black. At the hip, the median percentage change in BMD at 48 weeks was -1.05% in the tenofovir disoproxil fumarate arms and 0.0% in the non-tenofovir disoproxil fumarate arms (between group P = 0.001). No interaction by sex was observed. The median percentage change in LS BMD was not different between arms.

CONCLUSIONS

Tenofovir disoproxil fumarate-containing PrEP was associated with significantly greater bone loss compared with maraviroc ± emtricitabine PrEP at the hip, but not the LS. The BMD changes at the hip were similar in magnitude in men and women.

Safety review of tenofovir disoproxil fumarate/emtricitabine pre-exposure prophylaxis for pregnant women at risk of HIV infection

Introduction: Pregnancy is a period of elevated HIV risk in high-burden settings, motivating the need for prevention tools that are both safe for use and effective during pregnancy. Oral pre-exposure prophylaxis (PrEP) containing tenofovir disoproxil fumarate (TDF) is recommended by the World Health Organization, including for pregnant and postpartum women at substantial risk of HIV infection. Although TDF use during pregnancy appears generally safe, data on PrEP use during pregnancy remain limited.Areas covered: We provide an overview of the clinical pharmacology and efficacy of daily TDF-based PrEP and summarize current evidence on the safety of PrEP use by pregnant HIV-uninfected women. We synthesize relevant studies assessing pregnancy outcomes among pregnant women who are living with HIV (WLHIV) and using TDF-based therapy. Finally, we make comparison to the safety profiles of other emerging HIV prevention options.Expert opinion: The current evidence indicates that TDF/FTC PrEP use is not associated with increased risk of adverse pregnancy and early infant growth outcomes. While safety data are generally reassuring, there is need for continued accrual of data on growth and pregnancy outcomes in PrEP research, implementation projects, and controlled pharmacokinetic studies to support current evidence and to understand concentration-efficacy relationship in pregnant women.

Recent Advances and New Challenges in Cisgender Women's Gynecologic and Obstetric Health in the Context of HIV

Although rates of human immunodeficiency virus (HIV) have declined globally over the past 10 years, United Nations Programme on HIV/AIDS estimates 1.7 million new infections occurred in 2019, with cisgender women (cis women) and girls accounting for 48%. Acquired immune deficiency syndrome-related illnesses are the leading global cause of mortality in cis women aged 15 to 49, and in many sub-Saharan Africa countries, young women face substantially higher HIV risk than their male counterparts. Drivers of this increased risk include sexual and reproductive health characteristics unique to cis women. This review discusses the role of sexually transmitted infections, contraception and pregnancy in HIV risk, and biomedical HIV prevention technologies available and in development.

Patient-Focused Selection of PrEP Medication for Individuals at Risk of HIV: A Narrative Review

Pre-exposure prophylaxis (PrEP) medication is a key component of the HIV prevention strategy in the US, which has been demonstrated to be highly effective in preventing HIV acquisition among individuals at risk. Two PrEP medications are currently approved: emtricitabine/tenofovir disoproxil fumarate (Truvada®; F/TDF) was approved by the US Food and Drug Administration in 2012, followed by emtricitabine/tenofovir alafenamide (Descovy®; F/TAF) in 2019. An ongoing randomized, double-blind, Phase 3 study (DISCOVER) demonstrated that F/TAF had non-inferior efficacy to F/TDF. While both medications have been found to be efficacious and well tolerated, several studies have identified that important differences exist with regards to pharmacokinetics, bone and renal safety profiles, and other factors. In this narrative review, we conducted a comprehensive evaluation of the populations at risk of HIV who may also be affected by, or at risk of, bone or renal conditions. We reviewed the safety profiles of F/TDF and F/TAF to develop an evidence-based algorithm for selecting the appropriate PrEP medication, based on biological, behavioral, and health characteristics of an individual at risk of HIV, and considered how the choice of PrEP medication may or may not compound safety concerns for these individuals. We identified that the introduction of F/TAF provides a valuable alternative to F/TDF, allowing the personalization of PrEP. F/TAF may be the preferred medication for cisgender men and transgender women at risk of HIV infection who are predisposed to, or already have, bone or renal conditions. While the approval of F/TAF is the first step in personalization of PrEP, additional options are still warranted to help accommodate the wide spectrum of individuals at risk of HIV with different lifestyles, medical histories, preferences, and requirements.

Low bone mass in people living with HIV on long-term anti-retroviral therapy: A single center study in Uganda

BACKGROUND

This study set out to determine the prevalence of low bone mass following long-term exposure to antiretroviral therapy in Ugandan people living with HIV.

METHODS

A cross-sectional study was conducted among 199 people living with HIV that had been on anti-retroviral therapy for at least 10 years. All participants had dual X-ray absorptiometry to determine their bone mineral density. The data collected included antiretroviral drug history and behavioral risk data Descriptive statistics were used to summarize the data. Inferential statistics were analyzed using multilevel binomial longitudinal Markov chain Monte Carlo mixed multivariate regression modelling using the rstanarm package.

RESULTS

One hundred ninety nine adults were enrolled with equal representation of males and females. The mean age was 39.5 (SD 8.5) years. Mean durations on anti-retroviral treatment was 12.1 (SD 1.44) years, CD4 cell count was 563.9 cells/mm3. 178 (89.5%) had viral suppression with <50 viral copies/ml. There were 4 (2.0%) and 36 (18%) participants with low bone mass of the hip and lumbar spine respectively. Each unit increase in body mass index was associated with a significant reduction in the odds for low bone mineral density of the hip and lumbar spine. The duration on and exposure to the various antiretroviral medications had no significant effect on the participant's odds for developing low bone mass. All the coefficients of the variables in a multivariable model for either hip or lumbar spine bone mass were not significant.

CONCLUSION

These results provide additional evidence that patients on long term ART achieve bone mass stabilization. Maintaining adequate body weight is important in maintaining good bone health in people on antiretroviral therapy.

Impact of postpartum tenofovir-based antiretroviral therapy on bone mineral density in breastfeeding women with HIV enrolled in a randomized clinical trial

Objectives

We set out to evaluate the effect of postnatal exposure to tenofovir-containing antiretroviral therapy on bone mineral density among breastfeeding women living with HIV.

Design

IMPAACT P1084s is a sub-study of the PROMISE randomized trial conducted in four African countries (ClinicalTrials.gov number NCT01066858).

Methods

IMPAACT P1084s enrolled eligible mother-infant pairs previously randomised in the PROMISE trial at one week after delivery to receive either maternal antiretroviral therapy (Tenofovir disoproxil fumarate / Emtricitabine + Lopinavir/ritonavir–maternal TDF-ART) or administer infant nevirapine, with no maternal antiretroviral therapy, to prevent breastmilk HIV transmission. Maternal lumbar spine and hip bone mineral density were measured using dual-energy x-ray absorptiometry (DXA) at postpartum weeks 1 and 74. We studied the effect of the postpartum randomization on percent change in maternal bone mineral density in an intention-to-treat analysis with a t-test; mean and 95% confidence interval (95%CI) are presented.

Results

Among 398/400 women included in this analysis, baseline age, body-mass index, CD4 count, mean bone mineral density and alcohol use were comparable between study arms. On average, maternal lumbar spine bone mineral density declined significantly through week 74 in the maternal TDF-ART compared to the infant nevirapine arm; mean difference (95%CI) -2.86 (-4.03, -1.70) percentage points (p-value <0.001). Similarly, maternal hip bone mineral density declined significantly more through week 74 in the maternal TDF-ART compared to the infant nevirapine arm; mean difference -2.29% (-3.20, -1.39) (p-value <0.001). Adjusting for covariates did not change the treatment effect.

Conclusions

Bone mineral density decline through week 74 postpartum was greater among breastfeeding HIV-infected women randomized to receive maternal TDF-ART during breastfeeding compared to those mothers whose infants received nevirapine prophylaxis.

Changes in Bone Mineral Density During and After Lactation in Ugandan Women With HIV on Tenofovir-Based Antiretroviral Therapy

Antiretroviral therapy (ART) in people living with human immunodeficiency virus (HIV) is associated with bone loss, but data are limited in lactation, when physiological bone mineral mobilization is occurring. This research charted changes in areal bone mineral density (aBMD) during and after lactation in Ugandan women with HIV (WWH) initiated onto ART in pregnancy, compared to women without HIV (REF). One-hundred WWH on tenofovir-based ART and 100 REF were enrolled in pregnancy. Lumbar spine (LS), total hip (TH), and whole-body-less-head (WBLH) aBMD were measured by dual-energy X-ray absorptiometry (DXA) at 2, 14, and 26 weeks of lactation, and at 3 months postlactation. The primary outcome was the difference between groups in mean percent change in LS aBMD between 2 and 14 weeks. Statistical analysis was performed in hierarchical repeated measures ANOVA models that corrected for multiple testing. Median age was 23.4 (IQR, 21.0 to 26.8) years. WWH had lower body weight. aBMD decreased in both groups during lactation, but WWH had greater decreases at TH (2-to-26 weeks: WWH [n = 63] -5.9% [95% CI, -6.4 to -5.4] versus REF [n = 64] -4.3% [95% CI, -4.8 to -3.8]; group*time point interaction p = .008). Decreases in LS aBMD were similar in WWH and REF (2-to-26 weeks: -2.0% [95% CI, -2.5 to -1.5]), although there was a tendency toward a smaller decrease in WWH between 2 and 14 weeks (WWH [n = 77] -1.8% [95% CI, -2.2 to -1.4] versus REF [n = 69] -2.9% [95% CI, -3.3 to -2.5]; group*time point interaction p = .08). Postlactation, LS aBMD was higher relative to week 2 in both groups. TH and WBLH aBMD did not return to week 2 values in WWH but did in REF (TH postlactation versus week 2: WWH [n = 61] -3.1% [95% CI, -3.6 to -2.6]; REF [n = 29] +0.1% [95% CI, -0.9 to +1.1]). These data show accentuated bone loss during lactation and only partial skeletal recovery by 3 months postlactation in Ugandan WWH on tenofovir-based ART. Studies are ongoing to understand longer-term consequences for bone health. © 2020 The Authors. Journal of Bone and Mineral Research published by American Society for Bone and Mineral Research.

People living with HIV and fracture risk

PLHIV have an increased risk of osteoporosis and fractures when compared with people of the same age and sex. In this review, we address the epidemiology and the pathophysiology of bone disease and fractures in PLHIV. The assessment of fracture risk and fracture prevention in these subjects is also discussed. The spectrum of HIV-associated disease has changed dramatically since the introduction of potent antiretroviral drugs. Today, the survival of people living with HIV (PLHIV) is close to that of the general population. However, the longer life-span in PLHIV is accompanied by an increased prevalence of chronic diseases. Detrimental effects on bone health are well recognised, with an increased risk of osteoporosis and fractures, including vertebral fractures, compared to the general population. The causes of bone disease in PLHIV are not fully understood, but include HIV-specific risk factors such as use of antiretrovirals and the presence of chronic inflammation, as well as traditional risk factors for fracture. Current guidelines recommend the use of FRAX to assess fracture probability in PLHIV age ≥ 40 years and measurement of bone mineral density in those at increased fracture risk. Vitamin D deficiency, if present, should be treated. Bisphosphonates have been shown to increase bone density in PLHIV although fracture outcomes are not available.

Bone Update: Is It Still an Issue Without Tenofovir Disoproxil Fumarate?

PURPOSE OF REVIEW

In the era of modern bone-friendly antiretroviral therapy (ART) regimens for people living with HIV (PLWH), this review discusses the research gaps and management concerns that remain for individuals who have already been exposed to ART with negative effects on bone metabolism, especially children and adolescents who have not acquired peak bone mass, and older adults who have additional risk factors for fracture.

RECENT FINDINGS

Data now support the use of avoidance of TDF and use of bone-friendly regimens that include integrase strand transfer inhibitors in PLWH with increased risk of fracture for either ART initiation or switch. Despite significant advances in our understanding of ART choice for PLWH with regard to bone health, additional diagnostic tests to determine fracture risk and management strategies beyond ART choice are necessary, especially in vulnerable PLWH populations, such as children and adolescents and older adults.

Bone Mineral Density, Body Composition, and Mineral Homeostasis Over 24 Months in Urban South African Women With HIV Exposed to Antiretroviral Therapy

Human immunodeficiency virus- (HIV-) infection and antiretroviral therapy (ART) exposure are associated with bone loss. African data are limited despite the region's HIV burden. Of 247 ART-naïve, premenopausal, urban, black African women aged 33.9 ± 6.6 years from Soweto, South Africa, measured at baseline, 110 underwent anthropometry, DXA, and blood and urine collections at 12 and 24 months; 39 were HIV-negative (Nref), 28 were people with HIV (PWH) not ART-exposed for the duration of the study (ART-N), and 43 were PWH who were ART-exposed within the first 12 months (ART-Y). At baseline, the ART-Y group had lower BMI and fat mass than the Nref group. Within 12 months of ART initiation, areal bone mineral density (aBMD) had decreased at the lumbar spine and at the whole body less head, despite increased weight, and hip aBMD had not increased in line with the Nref group. There was no evidence of further bone changes between 12 and 24 months. By 24 months, the ART-Y women had gained weight and fat mass, but remained lighter with less fat than the Nref women. ART initiation normalized the low serum albumin of the ART-Y group at baseline, but was associated with elevated bone turnover markers at 12 and 24 months. Vitamin D status and renal phosphate handling were normal. ART-N had similar aBMD and other characteristics to the Nref group throughout, except unlike the Nref group, weight and fat mass did not increase and serum albumin decreased. This study in African women of childbearing age demonstrated that the bone loss that had occurred in these PWH after ART initiation did not continue after 12 months and that bone loss did not occur in ART-unexposed PWH over 2 years. At 24 months, despite gains in weight and fat mass, ART-exposed women remained lighter, with lower aBMD, fat mass, and higher bone turnover than women without HIV. More studies are required to establish if the bone loss and fat gain reverse, stabilize, or continue with further ART exposure, particularly during and after menopause. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Changes in Bone Mass After Discontinuation of Preexposure Prophylaxis With Tenofovir Disoproxil Fumarate/Emtricitabine in Young Men Who Have Sex With Men: Extension Phase Results of Adolescent Trials Network Protocols 110 and 113

Human immunodeficiency virus-seronegative men aged 15-22 years who lost bone mineral density (BMD) during tenofovir disoproxil fumarate/emtricitabine preexposure prophylaxis (PrEP) showed BMD recovery 48 weeks following PrEP discontinuation. Lumbar spine and whole body BMD z-scores remained below baseline 48 weeks off PrEP in participants aged 15-19 years. Clinical Trials Registration. NCT01772823 (ATN 110) and NCT01769456 (ATN 113).

Reduced bone mineral density among HIV infected patients on anti-retroviral therapy in Blantyre, Malawi: Prevalence and associated factors

INTRODUCTION

Use of tenofovir based anti-retroviral therapy (ART) in HIV patients is associated with low bone mineral density (BMD). Low BMD predisposes people living with HIV (PLWHIV) to fractures thereby increasing morbidity and mortality. Since the introduction of tenofovir based ARV regimens in 2011, information on the prevalence of low BMD in PLWHIV and receiving ART is still scarce in Malawi. This study aimed to determine the prevalence and associated factors of low BMD among adults living with HIV and receiving ART in Blantyre, Malawi.

METHODOLOGY

This was a cross sectional study involving 282 HIV-positive adults of whom 102 (36%) were males. The participants aged 18-45 years were recruited from three primary and one tertiary health care facilities. Patients with no other comorbidities or conditions associated with low BMD and on ART >12 months were included. Data on BMD (femoral neck and lumbar spine) were collected using Dual-Energy X-ray Absorptiometry (DEXA). The International Physical Activity Questionnaire (IPAQ) was used to assess the physical activity (PA) levels. Participants' body weight (kg) and height (m) were also measured. Descriptive statistics, Chi-Square test and multivariable logistic regression were used to analyse data.

RESULTS

Mean age of participants was 37(± 6.4) years, mean duration on ART was 5(± 3.5) years and mean body mass index (BMI) was 23(± 4.5) kg/m2. Twenty percent (55) had reduced BMD. More males (28%) had reduced BMD than females (14%) (p = 0.04). There was a significant association between lumbar BMD and femoral neck BMD (r = 0.66,p<0.001). However, on average, lumbar BMD (g/cm2) was significantly lower than the femoral BMD (p < 0.001). Participants with low PA level (OR 1.23,p = 0.6) had higher odds of having reduced BMD compared to those with high PA level.

CONCLUSIONS AND RECOMMENDATION

Prevalence of reduced BMD is high among PLWHIV in Malawi especially male Malawian adults. Occurrence of low BMD is associated with low PA level. There is need for health care providers to routinely monitor BMD and PA levels of this population.

The effect of tenofovir disoproxil fumarate on bone mineral density: a systematic review and meta-analysis

BACKGROUND

We conducted a systematic review and meta-analysis (CRD#42017070552) to quantify the impact of oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) on bone mineral density (BMD) and the risk of osteoporosis, low bone mass and fractures, among people taking it as pre-exposure prophylaxis (PrEP), HIV treatment and HBV treatment.

METHODS

We searched MEDLINE and EMBASE for randomized controlled trials published from 1997-2018 reporting BMD, osteoporosis, low bone mass and/or fractures in treatment-naive patients taking compared with not taking TDF for 48 ±4 weeks. We pooled outcomes using DerSimonian random-effects models.

RESULTS

Our search yielded 5,178 abstracts, representing 3,865 articles, with 25 meeting the inclusion criteria. TDF was associated with greater BMD decline when taken as PrEP (lumbar spine: mean difference [MD]=-0.82%, 95% CI=-1.28, -0.37%, I²=38%; total hip: MD=-0.81%, 95% CI=-1.22, -0.40%, I²=48%) and HIV treatment (lumbar spine: MD=-1.62%, 95% CI=-2.30, -0.95%, I²=93%; total hip: MD=-1.75%, 95% CI=-2.08, -1.42%, I²=83%; femoral neck: MD=-1.26%, 95% CI=-2.15, -0.38%, I²=43%) in comparison to those not taking TDF. Eight studies reported on incident osteoporosis or low bone mass, with variable results. Pooled results from five PrEP studies showed that TDF was not associated with increased fractures compared with no PrEP (RR=1.12, 95% CI=0.752, 1.74, I²=26%).

CONCLUSIONS

TDF caused greater decreases in BMD than did comparators when used for all three indications and the magnitude of this decrease was larger for HIV treatment compared with PrEP. Fractures were not increased among PrEP patients. The clinically significant BMD decline caused by TDF and current expansion of PrEP use suggest attention to the adverse bone effects of TDF will increase in importance.

Probenecid-Boosted Tenofovir: A Physiologically-Based Pharmacokinetic Model-Informed Strategy for On-Demand HIV Preexposure Prophylaxis

Multiple doses of tenofovir disoproxil fumarate (TDF) together with emtricitabine is effective for HIV preexposure prophylaxis (PrEP). TDF is converted to tenofovir (TFV) in circulation, which is subsequently cleared via tubular secretion by organic ion transporters (OATs; OAT1 and OAT3). Using in vitro kinetic parameters for TFV and the OAT1 and OAT3 inhibitor probenecid, a bottom‐up physiologically‐based pharmacokinetic model was successfully developed for the first time that accurately describes the probenecid–TFV interaction. This model predicted an increase in TFV plasma exposure by 60%, which was within 15% of the observed clinical pharmacokinetic data, and a threefold decrease in renal cells exposure following coadministration of a 600 mg TDF dose with 2 g probenecid. When compared with multiple‐dose regimens, a single‐dose probenecid‐boosted TDF regimen may be effective for HIV PrEP and improve adherence and safety by minimizing TFV‐induced nephrotoxicity by reducing TFV accumulation in renal cells.

Advancing HIV Biomedical Prevention Research for At-Risk Adolescents

Despite significant additions to the HIV prevention toolbox, infection rates across the United States continue to rise among vulnerable adolescents and young adults. Access to these interventions by youth at risk for HIV is limited by the lack of data about their safety and use, compounding the myriad contextual barriers to effectively preventing HIV in this group. The NIH-funded Adolescent Trials Network implemented an innovative approach to the inclusion of adolescents at risk for HIV infection who consented for their own participation in the first adolescent study of HIV pre-exposure prophylaxis (PrEP). This model of mature minor consent was supported by state-based adolescent treatment statutes that extend an adolescent's ability to consent to participation in research with a sufficient prospect of clinical benefit from the intervention to justify the potential risks, and a balance of benefits and risks that is at least as favorable as available evidence-based alternatives. Important data on the safety and patterns of PrEP use by at-risk adolescents prompted the FDA to revise the label. The expanded indication of PrEP for HIV prevention in adolescents is hoped to inform clinical guidelines and provides a powerful tool to reduce new infections in the United States among vulnerable at-risk adolescents. Lessons learned from this years-long iterative endeavor have implications for improving access to the rapidly evolving landscape of HIV prevention modalities, including recently implemented studies of long-acting PrEP formulations designed to reduce the burden of daily adherence required by oral PrEP, a major clinical pitfall for adolescent clinicians and their patients.

Pre-Exposure Prophylaxis for HIV Prevention in Women: Current Status and Future Directions

Pre-exposure prophylaxis (PrEP) is a promising intervention to prevent HIV acquisition, with benefits both to the individual and to population-level health. PrEP is an opportunity to complement ongoing public health efforts to eliminate HIV. For women, PrEP can also serve as a gateway to access sexual and reproductive health (SRH) services. Clinical efficacy of PrEP was initially reported in women using a 1% tenofovir vaginal gel in 2010, followed by an efficacy trial of oral PrEP using TDF/FTC in men who have sex with men (MSM). Since then, further trials have reported efficacy in oral PrEP containing tenofovir in women and heterosexual men, while the subsequent trials for women using tenofovir gel reported no efficacy, stemming from difficulties in achieving adequate adherence. In an effort to offer women additional choices to oral PrEP, alternative modalities are being tested in clinical research, including long-acting injectable formulations and intra-vaginal rings. In 2015, a meta-analysis of clinic trials and open-label extension studies led to the World Health Organization (WHO) strongly recommending the provision of oral PrEP containing tenofovir for any person at substantial risk of HIV infection, irrespective of gender or population group. Currently, PrEP services for women around the world, including those who are either pregnant or breastfeeding, remain limited. Outside sub-Saharan Africa, most PrEP programmes are focused on MSM. South Africa, Kenya, and the USA have the greatest utilization of oral PrEP by women. Yet, since 2012, of the estimated > 300,000 people globally who have initiated PrEP, a minority are women. In this narrative review, we examine the most recent literature on clinical and implementation PrEP research among women. We highlight the high burden of disease related to common sexually transmitted infections (STIs) in women, and the opportunity to integrate PrEP and other HIV prevention services, STI case management, and family planning services, as part of a more robust package of SRH services. Raising awareness on PrEP amongst women and their healthcare providers, minimizing gaps in access, and ensuring adherence and persistence of PrEP during periods of risk are critical issues if PrEP can have a meaningful impact on reducing HIV incidence in women globally.

Impact of Estimated Pre-Exposure Prophylaxis (PrEP) Adherence Patterns on Bone Mineral Density in a Large PrEP Demonstration Project

Bone mineral density (BMD) declines due to tenofovir-containing pre-exposure prophylaxis (PrEP) have varied among PrEP demonstration projects, potentially related to variable adherence. Characterization of BMD changes in highly adherent individuals, estimated via tenofovir-diphosphate (TFV-DP) levels in dried blood spots (DBS), can assist clinicians when counseling patients. Cisgender men who have sex with men and transwomen in the optional dual-energy X-ray absorptiometry (DXA) substudy of a large, international, open-label PrEP demonstration project, the iPrEx-open-label extension (OLE) study underwent DXA scans and DBS collection every 24 weeks, with average weekly dosing adherence patterns (2, 4, and 7 doses/week) estimated from validated TFV-DP cut-offs. The mean percent BMD change was estimated in strata of average weekly adherence by using a linear mixed-effects model to calculate the BMD decline in highly adherent individuals on PrEP for the first time. DXA/DBS data were available for 254 individuals over a median of 24 weeks in iPrEx-OLE from June 2011 to December 2013. The percent decline in spine BMD was monotonically associated with strata of increasing average weekly adherence (p < .001 trend); the p value for trends using hip BMD measurements was .07. Individuals with estimated daily adherence experienced a 1.2% decrease in spine BMD and a 0.5% drop in hip BMD. In highly adherent PrEP users, we found a lower-than-expected drop in BMD when compared with previous studies. This drop is likely not clinically significant for most PrEP users. However, for those at the highest risk of fracture who plan prolonged PrEP use, alternate PrEP strategies could be considered.

Tenofovir Has Minimal Effect on Biomarkers of Bone Health in Youth with HIV Receiving Initial Antiretroviral Therapy

Both HIV infection and tenofovir disoproxil fumarate (TDF) treatment adversely impact bone metabolism and may lead to osteopenia, which has critical implications for youth with HIV (YWH). This study evaluates changes in the biomarkers of bone metabolism and inflammation among YWH receiving initial treatment with TDF- and non-TDF-containing antiretroviral therapies (ARTs). YWH [n = 23, median age 21 years (range 18-24), 87% male, 61% African American] were assessed for inflammatory and bone metabolism biomarkers at enrollment, after 48 weeks of TDF-containing ART, and 96 weeks of ART without TDF with continued viral suppression. Spearman's rank correlation evaluated biomarker associations. Bone alkaline phosphatase, parathyroid hormone, and osteopontin increased after TDF treatment. All fell after TDF was discontinued. Levels of RANKL and osteoprotegerin did not change throughout the study. There was little correlation between biomarkers of bone metabolism and either macrophage or lymphocyte activation at any time point. Our results establish baseline associations between bone metabolism and immune biomarkers for this population, and find that before CD4 T cell decline chronic inflammation does not perturb biomarkers of bone metabolism among YWH. The adverse effects of TDF on bone health may be marginal for YWH at the early stages of disease.

Effect of Vitamin D Supplementation on Bone Turnover Markers During HIV Pre-Exposure Prophylaxis Using Tenofovir Disoproxil Fumarate-Emtricitabine in Men Who Have Sex with Men

Pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate-emtricitabine (TDF-FTC) reduces bone mineral density in HIV-uninfected men who have sex with men (MSM). We hypothesized that PrEP with TDF-FTC would increase bone turnover markers (BTMs) at week 24 and that vitamin D supplementation from weeks 24 to 48 would blunt this increase. Participants were from a cohort of 398 MSM and transgender women who received daily TDF-FTC for PrEP. At week 24, a prospective intervention group initiated vitamin D3 4,000 IU daily. Concurrent controls were selected from the cohort who took ≤400 IU/day of vitamin D3 matched by age, race, and body mass index. The primary endpoint was the change in procollagen-I N-terminal propeptide (P1NP) from weeks 24 to 48. Paired t-tests were used to compare changes in BTMs between intervention and controls. Among 48 intervention-control pairs, median age was 33 years. At baseline, 68.9% of the intervention group and 77.3% of controls were vitamin D sufficient (≥20 ng/mL, p = .94). P1NP, C-telopeptide, parathyroid hormone (PTH), and 25-OH vitamin D3 did not increase significantly at week 24. P1NP fell by a mean ± SD of -27.6 ± 49.9 pg/mL from weeks 24 to 48 with vitamin D and -2.5 ± 40.2 pg/mL in controls (p = .01). There were no significant between-group differences in the weeks 24-48 change in C-telopeptide, PTH, or 25-OH vitamin D3. Vitamin D3 supplementation with 4,000 IU/day resulted in a significant reduction in the BTM P1NP compared with controls, suggesting that this intervention has potential to improve bone health during PrEP.

Preexposure Prophylaxis for the Prevention of HIV Infection: Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Effective prevention strategies for HIV infection are an important public health priority. Preexposure prophylaxis (PrEP) involves use of antiretroviral therapy (ART) daily or before and after sex to decrease risk of acquiring HIV infection.

OBJECTIVE

To synthesize the evidence on the benefits and harms of PrEP, instruments for predicting incident HIV infection, and PrEP adherence to inform the US Preventive Services Task Force.

DATA SOURCES

Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and EMBASE through June 2018, with surveillance through January 2019.

STUDY SELECTION

English-language placebo-controlled randomized clinical trials of oral PrEP with tenofovir disoproxil fumarate/emtricitabine or tenofovir disoproxil fumarate monotherapy; studies on the diagnostic accuracy of instruments for predicting incident HIV infection; and studies on PrEP adherence.

DATA EXTRACTION AND SYNTHESIS

Dual review of titles and abstracts, full-text articles, study quality, and data abstraction. Data were pooled using the Dersimonian and Laird random-effects model for effects of PrEP on HIV infection, mortality, and harms.

MAIN OUTCOMES AND MEASURES

HIV acquisition, mortality, and harms; adherence to PrEP; and diagnostic test accuracy and discrimination.

RESULTS

Fourteen RCTs (N = 18 837), 8 observational studies (N = 3884), and 7 studies of diagnostic accuracy (N = 32 279) were included. PrEP was associated with decreased risk of HIV infection vs placebo or no PrEP after 4 months to 4 years (11 trials; relative risk [RR], 0.46 [95% CI, 0.33-0.66]; I2 = 67%; absolute risk reduction [ARD], -2.0% [95% CI, -2.8% to -1.2%]). Greater adherence was associated with greater efficacy (RR with adherence ≥70%, 0.27 [95% CI, 0.19-0.39]; I2 = 0%) in 6 trials. PrEP was associated with an increased risk of renal adverse events (12 trials; RR, 1.43 [95% CI, 1.18-1.75]; I2 = 0%; ARD, 0.56% [95% CI, 0.09%-1.04%]) and gastrointestinal adverse events (12 trials; RR, 1.63 [95% CI, 1.26-2.11]; I2 = 43%; ARD, 1.95% [95% CI, 0.48%-3.43%]); most adverse events were mild and reversible. Instruments for predicting incident HIV infection had moderate discrimination (area under the receiver operating characteristic curve, 0.49-0.72) and require further validation. Adherence to PrEP in the United States in men who have sex with men varied widely (22%-90%).

CONCLUSIONS AND RELEVANCE

In adults at increased risk of HIV infection, PrEP with oral tenofovir disoproxil fumarate monotherapy or tenofovir disoproxil fumarate/emtricitabine was associated with decreased risk of acquiring HIV infection compared with placebo or no PrEP, although effectiveness decreased with suboptimal adherence.

Primary Care Physician Attitudes and Intentions Toward the Use of HIV Pre-exposure Prophylaxis in Adolescents in One Metropolitan Region

PURPOSE

Understanding the attitudes of physicians toward the use of pre-exposure prophylaxis (PrEP) for HIV prevention among youth is critical to improving access to PrEP. We examined PrEP-related attitudes among physicians who provide primary care to 13- to 21-year-old adolescents.

METHODS

Individual, in-depth, semistructured interviews were conducted with 38 physicians from adolescent medicine, family practice, internal medicine/medicine-pediatrics, obstetrics/gynecology, and pediatrics who care for any adolescents younger than 18 years. Interviews assessed familiarity with PrEP, perceived benefits and barriers to providing PrEP to adolescents, facilitating factors for prescribing PrEP, and likelihood of recommending and prescribing PrEP to adolescents.

RESULTS

Mean age was 44.6 years (standard deviation 10.9). Fourteen physicians (37%) reported being somewhat or very familiar with PrEP. Perceived benefits of prescribing PrEP included decreased acquisition/rates of HIV, improved provision of sexual health services, and improved patient awareness of HIV risk. Barriers to PrEP were reported at the patient (e.g., lack of acceptability to patients), provider (e.g., concerns about patient adherence, safety/side effects, parents as a barrier to PrEP use), and system (e.g., high cost) levels. Facilitating factors for prescribing PrEP included low cost/coverage by insurance, physician education about PrEP, patient educational materials, and clinical guidelines for PrEP use in youth. A higher proportion of physicians reported being highly or somewhat likely to recommend (N = 16, 42%) than prescribe PrEP (N = 13, 34%).

CONCLUSIONS

In this study of primary care physician attitudes toward PrEP prescribing for adolescents, physicians identified numerous barriers to providing PrEP. Addressing these barriers may increase adolescents' access to PrEP.

Pre-exposure Prophylaxis for HIV Infection in the Older Patient: What can be Recommended?

Over the past 15 years, a significant increase in new HIV/AIDS diagnoses has been observed in the elderly population. This new epidemiological shift has been attributed to a longer sex life, lifestyle and changes in sexual behavior, poor sexual health education, and misconceptions about the absence of sexually transmitted disease in later life. Although many biomedical and behavioral interventions have proven useful to prevent sexually transmitted infections and HIV, pre-exposure prophylaxis (PrEP) has been shown to be the most successful biomedical intervention to prevent HIV in high-risk individuals. This approach is based on delivering a fixed dose of tenofovir disoproxil fumarate (300 mg), alone or combined with emtricitabine (300/200 mg) daily or on demand, before and after sexual intercourse. Despite the consistent number of clinical trials proving the effectiveness and safety of this strategy, no studies have focused specifically on elderly people. These individuals, who may benefit substantially from (PrEP), are at a higher risk of experiencing side effects secondary to tenofovir exposure. This review critically discusses the efficacy and safety of PrEP in people aged over 50 years and translates the knowledge of tenofovir management in patients with HIV into monitoring and stopping rules to be used in this special population. We provide practical recommendations to properly identify PrEP candidates among older adults. Furthermore, we define correct case management before and during PrEP  delivery, and we suggest stopping rules and alternative sexually transmitted infection prevention strategies.

Acceptability and tolerability of and adherence to HIV preexposure prophylaxis among Toronto gay and bisexual men: a pilot study

BACKGROUND

Preexposure prophylaxis is efficacious at preventing HIV infection, but concerns persist about adherence and sexually transmitted infections (STIs). We assessed preexposure prophylaxis acceptability, adherence and clinical outcomes in a pilot demonstration project.

METHODS

HIV-uninfected adult gay and bisexual men who scored 10 or higher on a validated HIV risk score (HIV Incidence Risk Index for MSM) and reported condomless receptive anal sex were sequentially enrolled into a 1-year open-label single-arm pilot study of daily oral therapy with tenofovir disoproxil fumarate/emtricitabine in Toronto. The primary outcome was acceptability of preexposure prophylaxis. Secondary outcomes were preexposure prophylaxis adherence (4-d recall, pill count and dried blood spot analysis), HIV seroconversion, STIs and adverse events.

RESULTS

Of the 86 men screened, 52 were enrolled. Participants were mostly young (median age 33 yr [interquartile range (IQR) 28-37 yr) white (38 [73%]) gay (49 [94%]) men. Preexposure prophylaxis acceptability was high: all participants reported their experience as "good" or "very good." The median adherence rate was high, at 100% (IQR 95%-100%) by self-report and 96.9% (IQR 93.4%-98.4%) by pill count. Dried blood spot analysis suggested that doses were taken 4-7 days/week at 88.7% (173/195) of month 3-12 visits. No cases of HIV seroconversion occurred, but 25 participants (48%) experienced at least 1 bacterial STI, with incidence rates per 100 person-years of 32.8, 32.8, 8.2 and 8.2 for chlamydia, gonorrhea, syphilis and lymphogranuloma venereum, respectively. No adverse events led to discontinuation of prophylaxis, but the estimated glomerular filtration rate declined by 0.22 mL/min per month.

INTERPRETATION

Preexposure prophylaxis was associated with high adherence and acceptability and no HIV infections in this study. Frequent STIs and clinically unapparent toxic renal effects reinforce the need for ongoing vigilance.

TRIAL REGISTRATION

ClinicalTrials. gov, no. NCT02149888.

Management of Reduced Bone Mineral Density in HIV: Pharmacological Challenges and the Role of Exercise

Low bone mineral density is becoming more common among people living with HIV following the use of current antiretroviral therapy drugs such as tenofovir. Although pharmacological therapies used to treat low bone mineral density are associated with adverse effects and may increase the pill burden in people living with HIV who are already burdened by antiretroviral therapy drugs, non-pharmacological strategies to prevent and treat reduced bone mineral density resulting from antiretroviral therapy drugs in people living with HIV have not been fully explored. Despite evidence that exercise is effective in increasing bone mineral density, effects of exercise on low bone mineral density resulting from antiretroviral therapy drugs in HIV infected individuals are still unknown. This review highlights gaps in the strategies used to manage reduced bone mineral density resulting from antiretroviral therapy drugs and focuses on exercise as an alternative or adjunctive strategy.

Tenofovir disoproxil fumarate as pre-exposure prophylaxis for HIV prevention in women with osteoporosis: a case report and review of the literature

Pre-exposure prophylaxis (PrEP), using tenofovir disoproxil fumarate (TDF), can effectively prevent HIV acquisition. However, TDF can cause changes in bone mineral density (BMD). There is little information on the use of PrEP among patients with bone disease. We present a case report of a female with pre-existing osteoporosis who was prescribed PrEP. Over the course of 9 months of consistent PrEP use, verified by dried blood spot testing, we report a lack of BMD changes on serial dual-emission X-ray absorptiometry scans in this patient. This case can inform PrEP care for patients with pre-existing bone disease.

Recent advances in pre-exposure prophylaxis for HIV

Although pre-exposure prophylaxis (PrEP)-the use of antiretroviral drugs by non-infected people to prevent the acquisition of HIV-is a promising preventive option, important public health questions remain. Daily oral emtricitabine (FTC)-tenofovir disoproxil fumarate (TDF) is highly efficacious in preventing the acquisition of HIV in people at risk as a result of a range of different types of sexual exposure. There is good evidence of efficacy in women and men, and when men who have sex with men use event based dosing. Studies have been conducted in several countries and epidemics. Because adherence to this treatment varies greatly there are questions about its public health benefit. Oral FTC-TDF is extremely safe, with minimal impact on kidney, bone, or pregnancy outcomes, and there is no evidence that its effectiveness has been reduced by risk compensation during open label and programmatic follow-up. It is too early to assess the impact of this treatment on the incidence of sexually transmitted infections (STIs) at a population level. Many challenges remain. Access to pre-exposure prophylaxis is limited and disparities exist, including those governed by race and sex. Different pricing and access models need to be explored to avoid further widening inequalities. The optimal combination prevention program needs to be defined, and this will depend on local epidemiology, service provision, and cost effectiveness. This review updates the evidence base for pre-exposure prophylaxis regarding its effectiveness, safety, and risk compensation.

Adolescent pre-exposure prophylaxis for HIV prevention: current perspectives

Adolescents are a critical population that is disproportionately impacted by the HIV epidemic. More than 2 million adolescents between the age group of 10 and 19 years are living with HIV, and millions are at risk of infection. HIV risks are considerably higher among girls, especially in high-prevalence settings such as eastern and southern Africa. In addition to girls, there are other vulnerable adolescent subgroups, such as teenagers, who use intravenous (IV) drugs, gay and bisexual boys, transgender youth, male sex workers, and people who fall into more than one of these categories. Pre-exposure prophylaxis (PrEP) is a new intervention for people at high risk for acquiring HIV, with an estimated HIV incidence of >3%. Recent data from trials show evidence of the efficacy of PrEP as a powerful HIV prevention tool in high-risk populations, including men who have sex with men, HIV-1-serodiscordant heterosexual couples, and IV drug users. The reported efficacy in those trials of the daily use of oral tenofovir, alone or in combination with emtricitabine, to prevent HIV infection ranged from 44% to 75% and was heavily dependent on adherence. Despite the proven efficacy of PrEP in adult trials, concerns remain about its feasibility in real-life scenarios due to stigma, cost, and limited clinician experience with PrEP delivery. Recent studies are attempting to expand the inquiry into the efficacy of such HIV prophylaxis approaches in adolescent populations, but there are still many gaps in knowledge, and no country has yet approved it for use with adolescents. The aim of this review was to identify and summarize the evidence from studies on PrEP for adolescents. We have compiled and reviewed published studies focusing on safety, feasibility, adherence to therapeutics, self-perception, and legal issues related to PrEP in people aged between 10 and 24 years.

Brief Report: Recovery of Bone Mineral Density After Discontinuation of Tenofovir-Based HIV Pre-exposure Prophylaxis

BACKGROUND

Oral tenofovir disoproxil fumarate (TDF) for HIV prevention and treatment is associated with decreases in bone mineral density (BMD). Previous reports suggest that these changes may be reversible after discontinuation of TDF.

SETTING

A metabolic substudy of 498 participants in a randomized, placebo-controlled HIV prevention trial of oral coformulated TDF with emtricitabine (TDF/FTC, Truvada) for HIV pre-exposure prophylaxis (PrEP) enrolling a global sample of men who have sex with men and trans women.

METHODS

Participants underwent dual X-ray absorptiometry to quantify bone mineral density (BMD) in the hip and spine during PrEP and at 2 visits after stopping (median of 23 and 79 weeks post-PrEP, respectively). Results are stratified by pharmacologic measure of TDF/FTC adherence.

RESULTS

There was no significant difference in change in hip/spine BMD at any time point between placebo and those with low adherence. Adherent participants had a mean (standard error) BMD change at TDF/FTC discontinuation of -1.02% (0.24) in the hip and -1.84% (0.36) in the spine. After stop, annualized BMD increases of 1.13% per year (0.27) in hip and 1.81% per year (0.36) in spine BMD were observed in adherent participants compared with 0.19% (0.16) and 0.74% (0.21) in the placebo group, respectively (P = 0.003, both comparisons). On average, BMD returned to baseline levels by 1 year after PrEP stop. Recovery was consistent across age, baseline BMD z-score, and treatment duration.

CONCLUSIONS

Mean BMD returns to baseline levels within 12-18 months after TDF-based PrEP discontinuation in both hip and spine with consistency across participant subgroups.

CLINICAL TRIALS REGISTRATION

clinicaltrials.gov NCT00458393.

Changes in Bone Mineral Density, Body Composition, Vitamin D Status, and Mineral Metabolism in Urban HIV-Positive South African Women Over 12 Months

Human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) are associated with bone loss and poor vitamin D status in white populations, though their relative roles are not known. No previous studies have examined longitudinal changes in areal bone mineral density (aBMD), measured by dual-energy X-ray absorptiometry (DXA), or in vitamin D status in HIV-positive African women. Of 247 premenopausal, urban, black African women from Soweto, South Africa, initially recruited, 187 underwent anthropometry, DXA scanning and blood and urine collections at both baseline and 12 months. Of these, 67 were HIV-negative throughout (Nref), 60 were HIV-positive with preserved CD4 counts at baseline (Ppres), and 60 were HIV-positive with low CD4 counts at baseline, eligible for ART by South African standards of care at the time (Plow). No participant had been exposed to ART at baseline. By 12 months, 51 Plow women had initiated ART, >85% of whom took combined tenofovir disoproxil fumarate (TDF), lamivudine, and efavirenz. By 12 months, Plow and Nref, but not Ppres, increased in body weight and fat mass (group-by-timepoint p ≤ 0.001, p = 0.002, respectively). Plow had significant decreases in aBMD of 2% to 3%, before and after size adjustment, at the femoral neck (p ≤ 0.002) and lumbar spine (p ≤ 0.001), despite significant weight gain. These decreases were associated with increased bone turnover but there were no significant differences or changes over time in vitamin D status, serum phosphate concentrations, or renal phosphate handling. Excluding data from nine Plow women unexposed to ART and 11 Ppres women who had initiated ART accentuated these findings, suggesting the bone loss in Plow was related to ART exposure. This is the first study describing DXA-defined bone loss in HIV-positive Sub-Saharan African women in association with ART. Further work is required to establish if bone loss continues with ongoing ART and, if so, whether this results in increased fracture rates. © 2017 American Society for Bone and Mineral Research.

Pre-exposure prophylaxis for HIV prevention in women: current perspectives

There are ~900,000 new HIV infections among women every year, representing nearly half of all new HIV infections globally. In the US, nearly one-fifth of all new HIV infections occur among women, and women from racial and ethnic minority communities experience disproportionately high rates of new HIV infections. Thus, there is a need to develop and implement effective HIV prevention strategies for women in the US and internationally, with a specific need to advance strategies in minority communities. Previous studies have demonstrated that oral HIV pre-exposure prophylaxis (PrEP), the use of antiretroviral medications by HIV-uninfected persons to prevent HIV acquisition, can reduce HIV incidence among women who are adherent to PrEP. However, to date, awareness and uptake of PrEP among women have been very limited, suggesting a need for innovative strategies to increase the knowledge of and access to PrEP among women in diverse settings. This narrative review summarizes the efficacy and safety data of PrEP in women, discusses considerations related to medication adherence for women who use PrEP, and highlights behavioral, social, and structural barriers to maximize the effectiveness of PrEP in women. It also reviews novel modalities for PrEP in women which are being developed and tested, including topical formulations and long-acting injectable agents that may offer advantages as compared to oral PrEP and proposes a community-oriented, social networking framework to increase awareness of PrEP among women. If women are provided with access to PrEP and support to overcome social and structural barriers to adhere to PrEP, this prevention strategy holds great promise to impact the HIV epidemic among women in the US and globally.

Bone Loss in HIV Infection

Human immunodeficiency virus (HIV) infection is an established risk factor for low bone mineral density (BMD) and subsequent fracture, and treatment with combination antiretroviral therapy (cART) leads to additional BMD loss, particularly in the first 1-2 years of therapy. The prevalence of low BMD and fragility fracture is expected to increase as the HIV-infected population ages with successful treatment with cART. Mechanisms of bone loss in the setting of HIV infection are likely multifactorial, and include viral, host, and immune effects, as well as direct and indirect effects of cART, particularly tenofovir disoproxil fumarate (TDF) and the protease inhibitors (PIs). Emerging data indicate that BMD loss following cART initiation can be mitigated by prophylaxis with either long-acting bisphosphonates or vitamin D and calcium supplementation. In addition, newer antiretrovirals, particularly the integrase strand transfer inhibitors and tenofovir alafenamide (TAF), are associated with less intense bone loss than PIs and TDF. However, further studies are needed to establish optimal bone sparing cART regimens, appropriate screening intervals, and preventive measures to address the rising prevalence of fragility bone disease in the HIV population.

Tenofovir disoproxil fumarate safety for women and their infants during pregnancy and breastfeeding

OBJECTIVES

Pregnant/lactating women in some sub-Saharan Africa settings are at substantial risk of HIV acquisition and could benefit from preexposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF), but safety data in pregnancy/lactation are limited.

DESIGN

Systematic data review through August 2016.

METHODS

We reviewed research reports/conference abstracts with maternal/child adverse outcome data in HIV-infected and HIV-uninfected pregnant/lactating women receiving TDF alone or in combination with other drugs compared with non-TDF regimens.

RESULTS

In total, 26 articles in HIV-infected and seven in HIV-uninfected women were identified. No statistically significant differences were observed between TDF and comparison non-TDF regimens in pregnancy incidence, stillbirth/pregnancy loss, preterm delivery less than 37 weeks, low birth weight <2500/<1500 g, small for gestational age, birth defects, or infant (>14 days) or maternal mortality. One study reported significantly higher very preterm delivery (<34 weeks) and neonatal mortality with TDF versus non-TDF antiretroviral therapy (ART), but no significant difference between TDF ART and zidovudine/single-dose nevirapine. Most studies report normal infant linear growth; one study showed slightly lower, and one higher 1-year length-for-age z-score in TDF ART-exposed infants. No significant differences were reported in abnormal laboratory values or bone markers between TDF and non-TDF-exposed infants in four studies. Lower maternal bone mineral density was observed at 74 weeks postpartum in breastfeeding women on TDF ART compared with no ART in one study.

CONCLUSION

Given available safety data, there does not appear to be a safety-related rationale for prohibiting PrEP during pregnancy/lactation or for discontinuing PrEP in HIV-uninfected women receiving PrEP who become pregnant and are at continuing risk of HIV acquisition.

HIV and Bone Complications: Understudied Populations and New Management Strategies

The higher risk of osteoporosis and fracture associated with HIV infection and certain antiretrovirals has been well established and the need for risk stratification among older adults increasingly recognized. This review focuses upon emerging data on bone complications with HIV/HCV coinfection, in children and adolescents, and with pre-exposure prophylaxis (PrEP), as well as new management strategies to minimize the negative effects of ART on bone.

Effectiveness and safety of oral HIV preexposure prophylaxis for all populations

OBJECTIVE

Preexposure prophylaxis (PrEP) offers a promising new approach to HIV prevention. This systematic review and meta-analysis evaluated the evidence for use of oral PrEP containing tenofovir disoproxil fumarate as an additional HIV prevention strategy in populations at substantial risk for HIV based on HIV acquisition, adverse events, drug resistance, sexual behavior, and reproductive health outcomes.

DESIGN

Rigorous systematic review and meta-analysis.

METHODS

A comprehensive search strategy reviewed three electronic databases and conference abstracts through April 2015. Pooled effect estimates were calculated using random-effects meta-analysis.

RESULTS

Eighteen studies were included, comprising data from 39 articles and six conference abstracts. Across populations and PrEP regimens, PrEP significantly reduced the risk of HIV acquisition compared with placebo. Trials with PrEP use more than 70% demonstrated the highest PrEP effectiveness (risk ratio = 0.30, 95% confidence interval: 0.21-0.45, P < 0.001) compared with placebo. Trials with low PrEP use did not show a significantly protective effect. Adverse events were similar between PrEP and placebo groups. More cases of drug-resistant HIV infection were found among PrEP users who initiated PrEP while acutely HIV-infected, but incidence of acquiring drug-resistant HIV during PrEP use was low. Studies consistently found no association between PrEP use and changes in sexual risk behavior. PrEP was not associated with increased pregnancy-related adverse events or hormonal contraception effectiveness.

CONCLUSION

PrEP is protective against HIV infection across populations, presents few significant safety risks, and there is no evidence of behavioral risk compensation. The effective and cost-effective use of PrEP will require development of best practices for fostering uptake and adherence among people at substantial HIV risk.