Weight Gain After HIV Therapy Initiation: Pathophysiology and Implications

Low CD4 counts predict excessive weight gains during first-line treatment for HIV

BACKGROUND

Weight gain is common after antiretroviral initiation, especially among females, those of black race and lower baseline CD4, although this may potentially be due to lower baseline weight. Use of tenofovir disoproxil fumarate or efavirenz can suppress weight gain.

METHODS

Data were pooled from the ADVANCE (n = 1053), NAMSAL (n = 613) and WHRI001 (n = 536) trials investigating first-line regimen. Week 96 weight and body mass index (BMI) was stratified by baseline CD4. Multivariable models of weight change and incident obesity (BMI ≥30 kg/m2) were adjusted for baseline CD4, age, sex, tenofovir disoproxil fumarate, efavirenz, baseline BMI and trial.

RESULTS

Participants across all treatment arms experienced weight gain from baseline to week 96, with baseline CD4 count, baseline HIV RNA, tenofovir alafenamide and dolutegravir use, and female sex significant predictors. Mean unadjusted weight change was highest with CD4 < 100 (+8.6 kg; SD = 8.2) and lowest with CD4 ≥ 350 (+3.0 kg; SD = 6.5). This weight gain in CD4 < 100 was highest for participants on tenofovir alafenamide-inclusive treatment, such that absolute weight at week 96 was highest in the CD4 < 100 group. Although not statistically significant, obesity rate (BMI ≥ 30 kg/m2) in those taking TAF/FTC + DTG with CD4 < 100 overtook that seen in CD4 ≥ 350, despite lower baseline obesity prevalence. The unadjusted findings were corroborated in multivariable longitudinal models.

CONCLUSIONS

Participants with low CD4 may demonstrate significant 'overshoot' weight gain, in addition to 'return to health', with a trend towards increased risk of obesity when initiated on TAF/FTC + DTG. Use of tenofovir disoproxil fumarate and efavirenz were associated with smaller weight gains. Effective weight management strategies are needed, especially for individuals with low baseline CD4.

Gestational weight gain and adverse birth outcomes in South African women with HIV on antiretroviral therapy and without HIV: a prospective cohort study

INTRODUCTION

Outside of pregnancy, evidence shows that persons with HIV initiating or switching to dolutegravir (DTG)-based antiretroviral therapy (ART) experience greater weight gain compared to those on other ART classes. However, there are few data on the impact of DTG-based ART on gestational weight gain (GWG) in sub-Saharan Africa where HIV is most common. According to the National Academy of Medicine (NAM), GWG below and above NAM guidelines is associated with adverse birth outcomes. Therefore, the objective of this study was to describe GWG by HIV status and ART regimen, and examine the associations with adverse birth outcomes.

METHODS

We enrolled pregnant women with HIV (WHIV) and without HIV (≥18 years) in a peri-urban primary healthcare facility in Cape Town, South Africa between 2019 and 2022. GWG was study-measured at 24-28 (baseline) and 33-38 weeks gestation and converted to GWG rate (kg/week) in accordance with NAM guidelines. GWG z-scores were generated using the INTEGROWTH-21 and US standards to account for differing lengths of gestation. Birth outcome data were obtained from medical records. Associations of GWG z-score with adverse birth outcomes were assessed using multivariable linear or log-binomial regression.

RESULTS

Among 292 participants (48% WHIV), median age was 29 years (IQR, 25-33), median pre-pregnancy body mass index (BMI) was 31 kg/m2 (IQR, 26-36) and 20% were primiparous at baseline. The median weekly rate of GWG was 0.30 kg/week (IQR, 0.12-0.50), 35% had GWG below NAM standards (59% WHIV) and 48% had GWG above NAM standards (36% WHIV). WHIV gained weight more slowly (0.25 vs. 0.37 kg/week, p<0.01) than women without HIV. Weekly rate of GWG did not differ by ART regimen (DTG-based ART 0.25 vs. efavirenz-based ART 0.27 kg/week, p = 0.80). In multivariable analyses, GWG z-score was positively associated with continuous birth weight (mean difference = 68.53 95% CI 8.96, 128.10) and categorical high birth weight of >4000 g (RR = 2.18 95% CI 1.18, 4.01).

CONCLUSIONS

Despite slower GWG among WHIV, nearly half of all women gained weight faster than recommended by the NAM. GWG was positively associated with infant birth weight. Interventions to support healthy GWG in sub-Saharan Africa are urgently needed.

Exercise to Prevent Accelerated Vascular Aging in People Living With HIV

Given advances in antiretroviral therapy, the mortality rate for HIV infection has dropped considerably over recent decades. However, people living with HIV (PLWH) experience longer life spans coupled with persistent immune activation despite viral suppression and potential toxicity from long-term antiretroviral therapy use. Consequently, PLWH face a cardiovascular disease (CVD) risk more than twice that of the general population, making it the leading cause of death among this group. Here, we briefly review the epidemiology of CVD in PLWH highlighting disparities at the intersections of sex and gender, age, race/ethnicity, and the contributions of social determinants of health and psychosocial stress to increased CVD risk among individuals with marginalized identities. We then overview the pathophysiology of HIV and discuss the primary factors implicated as contributors to CVD risk among PLWH on antiretroviral therapy. Subsequently, we highlight the functional evidence of premature vascular dysfunction as an early pathophysiological determinant of CVD risk among PLWH, discuss several mechanisms underlying premature vascular dysfunction in PLWH, and synthesize current research on the pathophysiological mechanisms underlying accelerated vascular aging in PLWH, focusing on immune activation, chronic inflammation, and oxidative stress. We consider understudied aspects such as HIV-related changes to the gut microbiome and psychosocial stress, which may serve as mechanisms through which exercise can abrogate accelerated vascular aging. Emphasizing the significance of exercise, we review various modalities and their impacts on vascular health, proposing a holistic approach to managing CVD risks in PLWH. The discussion extends to critical future study areas related to vascular aging, CVD, and the efficacy of exercise interventions, with a call for more inclusive research that considers the diversity of the PLWH population.

Expanding the human gut microbiome atlas of Africa

Population studies are crucial in understanding the complex interplay between the gut microbiome and geographical, lifestyle, genetic, and environmental factors. However, populations from low- and middle-income countries, which represent ~84% of the world population, have been excluded from large-scale gut microbiome research. Here, we present the AWI-Gen 2 Microbiome Project, a cross-sectional gut microbiome study sampling 1,803 women from Burkina Faso, Ghana, Kenya, and South Africa. By intensively engaging with communities that range from rural and horticultural to urban informal settlements and post-industrial, we capture population diversity that represents a far greater breadth of the world's population. Using shotgun metagenomic sequencing, we find that study site explains substantially more microbial variation than disease status. We identify taxa with strong geographic and lifestyle associations, including loss of Treponema and Cryptobacteroides species and gain of Bifidobacterium species in urban populations. We uncover a wealth of prokaryotic and viral novelty, including 1,005 new bacterial metagenome-assembled genomes, and identify phylogeography signatures in Treponema succinifaciens. Finally, we find a microbiome signature of HIV infection that is defined by several taxa not previously associated with HIV, including Dysosmobacter welbionis and Enterocloster sp. This study represents the largest population-representative survey of gut metagenomes of African individuals to date, and paired with extensive clinical biomarkers, demographic data, and lifestyle information, provides extensive opportunity for microbiome-related discovery and research.

Recent data on the role of antiretroviral therapy in weight gain and obesity in persons living with HIV

PURPOSE OF REVIEW

Antiretroviral therapy (ART) has long been implicated in fat alterations and weight variations leading to cardiometabolic consequences. Recent largely prescribed antiretrovirals (ARVs) from the integrase-strand-transfer-inhibitor (INSTI) class have been associated with excessive weight gain/obesity in a minority of persons with HIV (PWH). As well, in the nucleoside reverse transcriptase inhibitors (NRTI) class, tenofovir-alafenamide (TAF), often replacing tenofovir-disoproxil-fumarate (TDF), has been associated with weight gain, a worrying concern in the present worldwide obesogenic environment. The respective role of the different ARV, the risk factors and the mechanisms remain questionable.

RECENT FINDINGS

The INSTIs dolutegravir (DTG) and bictegravir (BIC) and TAF have a proper effect on weight gain, while efavirenz (EFV) and TDF inhibit it. These effects are reported in ART-naïve PWH, in addition to weight gain resulting from the return to health process, and in ART-controlled PWH. Also, INSTIs induce weight gain in adolescents and excessive weight gain during pregnancy. The effects of INSTIs and TAF are additive. Their trajectory differs. Most of the weight gain is observed during the initial 12-month period.The main risk factors are low CD4+ and high viral load (VL) in ART-naïve PWH, Black race or originating from some African countries and female gender. The role of age and BMI differs between studies. The reversibility of the effect of INSTI and TAF appears limited.Regarding the mechanisms, the INSTIs can directly alter adipose tissue in particular through inhibition of fat beiging, resulting in fat fibrosis and hypertrophy. Macrophage infiltration is decreased. The mechanisms explaining the opposite effects of TDF and TAF remain elusive.

SUMMARY

The specific impact of DTG, BIC and TAF on weight gain/obesity in PWH is confirmed in different populations independently of the weight limiting effect of EFV and TDF. ART-linked excessive weight gain is uncommon. African origin and female sex are risk factors that need to be considered. The mechanisms are better understood for INSTIs but unknown for TDF/TAF. The reversibility of weight gain/obesity when stopping INSTI or TAF remains limited.

Intersections between HIV and obesity in emerging economies

PURPOSE OF REVIEW

HIV epidemics are increasing in many emerging economy countries, whilst the very process of 'economic emergence' is obesogenic. Annual deaths related to obesity and overweight are now four times more than for HIV globally. We describe the intersections between HIV and obesity in emerging economies, and highlight potential mitigation options, including antiobesity medications (AOMs), which are safe and effective, but inaccessibly priced.

RECENT FINDINGS

We summarize what is known about weight-change in HIV and review strategies including public health policies and clinical interventions for emerging economy countries to fight obesity. We also illustrate the landscape from a selection of 'emerging economy' countries with available data from UNAIDS, World Bank and World Obesity Federation to visualize the developing challenges faced. AOM course prices are high in many countries, but could be manufactured and sold profitably for much less. We present lessons from the early HIV/AIDS movements on how to improve access and pricing for AOMs for people with HIV with obesity in emerging economy countries.

SUMMARY

We illustrate the complex intersectional issues that 'emerging economy countries' may experience, with a 'double burden' of increasing HIV and obesity epidemics, and explore potential mitigation options, focussing on AOM access and pricing.