Blood pressure trajectories and the mediated effects of body mass index and HIV-related inflammation in a mixed cohort of people with and without HIV in rural Uganda

A systematic review of mediation analysis frameworks in studies examining the determinants of cardiometabolic outcomes in people living with HIV

INTRODUCTION

Mediation analysis provides a more flexible mechanistic view of the causal relationship between HIV-related factors and cardiometabolic diseases. However, there is limited evidence on how mediation analysis is implemented in this specific research area. We aimed to describe the frameworks used in mediation analysis and examine how these analyses are conducted and reported in studies focusing on cardiometabolic outcomes among people living with HIV (PLWH).

METHODS

Following the PRISMA 2020 Guidelines, we comprehensively searched Medline, CINAHL, Africa-Wide Information and SCOPUS to identify observational studies that employed mediation analysis before October 2023. Two reviewers independently screened studies for eligibility. One reviewer performed data extraction, and two others reviewed the extracted information.

RESULTS

Nine studies met the inclusion criteria, predominantly focusing on the mediation effects of weight and obesity-related factors on the relationship between HIV serostatus, ART, and cardiometabolic outcomes. The review revealed a diverse application of both traditional and causal mediation frameworks. However, inconsistencies and gaps in reporting were noted, particularly in handling missing data, detailing identifiability assumptions, and the use of sensitivity analyses.

CONCLUSION

While some studies of cardiometabolic risks among PLWH have embraced causal mediation frameworks, their overall application remains limited. In addition, we identified notable inconsistencies and gaps in reporting practices. To advance the field, researchers should not only integrate more rigorous causal mediation methods but also closely follow established reporting guidelines, such as the AGReMA Statement, to ensure greater transparency, reliability, and impact of future research.

Hypertension among people living with human immunodeficiency virus in sub-Saharan Africa: a systematic review and meta-analysis

We performed a systematic review and meta-analysis of hypertension in people living with human immunodeficiency virus (HIV) in sub-Saharan Africa (SSA). We searched the PubMed, Google Scholar, African Index Medicus, and Embase databases to identify studies published from January 1, 2010, to December 31, 2021. We used a random-effects model to estimate the pooled prevalence of hypertension and mean SBP/DBP level on a sex-specific basis. We included 48 studies reporting data on a pooled sample of 193,843 people living with HIV (PLW-HIV) in SSA. The pooled mean SBP/DBP level was 120 (95% CI 113-128)/77 (95%CI 72-82) mmHg, while the overall pooled prevalence of hypertension was 21.9% (95% CI 19.9-23.9%). Further meta-regression analyses suggested that the prevalence of hypertension was 1.33 times greater in males, 1.23 times greater in individuals receiving antiretroviral therapy (ART) and 1.45 times greater in those individuals with a CD4-count ≥ 200. This meta-analysis of the contemporary pattern of BP levels among PLW-HIV in SSA, suggests that around one in five of such individuals also have hypertension. Given the further context of greater access to ART and subsequently greater longevity, study findings support calls to integrate cardiovascular management into routine HIV care.

Coprevalence and associations of diabetes mellitus and hypertension among people living with HIV/AIDS in Cameroon

BACKGROUND

The association between HIV infection and increased cardiometabolic risk, attributed to chronic inflammation in people living with HIV (PLWH) and/or antiretroviral therapy (ART) effects, has been inconsistent. In this study, we aimed to assess the associations of HIV-related factors with hypertension (HTN) and type-2 diabetes mellitus (T2DM), and the potential mediation effects of body mass index (BMI) in the associations between ART use and HTN or T2DM in PLWH in Cameroon.

METHODS

A cross-sectional study was conducted with 14,119 adult PLWH from Cameroon enrolled in the International epidemiology Databases to Evaluate AIDS (IeDEA) between 2016 and 2021. HTN was defined as systolic/diastolic blood pressure ≥ 140/90 mmHg and/or current use of antihypertensive medication, while T2DM was defined as fasting blood sugar ≥ 126 mg/dL and/or use of antidiabetic medications. Univariable and multivariable multinomial logistic regression analyses examined the associations of factors with HTN alone, T2DM alone, and both (HTN + T2DM). Mediation analyses were conducted to assess the potential mediation roles of BMI, while controlling for age, sex, and smoking.

RESULTS

Of the 14,119 participants, 9177 (65%) were women, with a median age of 42 (25th-75th percentiles: 35-51) years. Age > 50 years was associated with HTN alone, T2DM alone, and HTN + T2DM compared to the age group 19-29 years. Men had higher odds of having HTN + T2DM. Overweight and obesity were predictors of HTN alone compared to being underweight. WHO stages II and III HIV disease were inversely associated with HTN alone compared to stage I. The odds of diabetes alone were lower with ART use. BMI partially mediated the association between ART use and hypertension, with a proportion of mediation effect of 49.6% (all p < 0.02). However, BMI did not mediate the relationship between ART use and diabetes.

CONCLUSIONS

Traditional cardiovascular risk factors were strongly associated with hypertension among PLWH, while HIV-related exposures had smaller associations. BMI partially mediated the association between ART use and hypertension. This study emphasizes the importance of screening, monitoring, and managing HTN and T2DM in older, male, and overweight/obese PLWH. Further research on the associations of HIV disease stage and ART use with HTN and T2DM is warranted.

HIV-Associated Hypertension: Risks, Mechanisms, and Knowledge Gaps

HIV type 1 (HIV-1) is the causative agent of AIDS. Since the start of the epidemic, HIV/AIDS has been responsible for ≈40 million deaths. Additionally, an estimated 39 million people are currently infected with the virus. HIV-1 primarily infects immune cells, such as CD4+ (cluster of differentiation 4+) T lymphocytes (T cells), and as a consequence, the number of CD4+ T cells progressively declines in people living with HIV. Within a span of ≈10 years, HIV-1 infection leads to the systemic failure of the immune system and progression to AIDS. Fortunately, potent antiviral therapy effectively controls HIV-1 infection and prevents AIDS-related deaths. The efficacy of the current antiviral therapy regimens has transformed the outcome of HIV/AIDS from a death sentence to a chronic disease with a prolonged lifespan of people living with HIV. However, antiviral therapy is not curative, is challenged by virus resistance, can be toxic, and, most importantly, requires lifelong adherence. Furthermore, the improved lifespan has resulted in an increased incidence of non-AIDS-related morbidities in people living with HIV including cardiovascular diseases, renal disease, liver disease, bone disease, cancer, and neurological conditions. In this review, we summarize the current state of knowledge of the cardiovascular comorbidities associated with HIV-1 infection, with a particular focus on hypertension. We also discuss the potential mechanisms known to drive HIV-1-associated hypertension and the knowledge gaps in our understanding of this comorbid condition. Finally, we suggest several directions of future research to better understand the factors, pathways, and mechanisms underlying HIV-1-associated hypertension in the post-antiviral therapy era.

No Evidence for an Association of HIV and Antiviral Treatment With Changes in Framingham Cardiovascular Risk Score in the Ndlovu Cohort Study

BACKGROUND

HIV and antiretroviral therapy (ART) have been associated with increased cardiovascular disease (CVD) risk in high-income countries. The authors studied the longitudinal association between HIV and ART and nonlaboratory Framingham Risk Score (FRS) in a middle-income country.

METHODS AND RESULTS

This longitudinal analysis of the NCS (Ndlovu Cohort Study), South Africa used baseline to 36-month follow-up data. Demographics, HIV, ART status, and cardiometabolic measures were obtained. FRS was used as a CVD risk measure. Through linear mixed models, FRS trends over time and the association with HIV were studied. Analysis included 1136 participants, with 609 (54%) having HIV, and 495 (81%) taking ART. At baseline, 9.8% of participants had a high FRS. People living with HIV (PLHIV) had a 3.2% lower FRS than HIV-negative participants (P<0.001). FRS increased similarly for both groups over time. Other factors associated with FRS were secondary and higher education (ß value: -0.075, P<0.001; ß value: -0.084, P<0.001) and alcohol consumption (ß value: 0.011, P<0.001).

CONCLUSIONS

CVD risk increased for all participants over 36 months, suggesting classic risk factors rather than HIV status or ART to be drivers of CVD risk. People living with HIV had a significantly lower FRS than their HIV-negative counterparts, possibly related to HIV itself or a more frequent interaction with healthcare services. No association of HIV and ART with changes in FRS over 36 months was observed, suggesting the need for research using clinical endpoints to elucidate the effects of HIV and ART on CVD risk. Population-based prevention of CVD risk factors in sub-Saharan Africa is warranted, regardless of HIV status.

Correlates of physical activity among people living with and without HIV in rural Uganda

Background

Antiretroviral therapy (ART) has led to diminishing AIDS-related mortality but a concomitant increase in non-communicable diseases (NCDs) for people with HIV (PWH). Whereas physical activity (PA) has been shown to help prevent NCDs and NCD outcomes in other settings, there are few data on PA and its correlates among PWH in high-endemic settings. We aimed to compare PA by HIV serostatus in rural Uganda.

Methods

We analysed data from the UGANDAC study, an observational cohort including PWH in ambulatory HIV care in Mbarara, Uganda, and age- and gender-matched people without HIV (PWOH). Our primary outcome of interest was PA, which we assessed using the International Physical Activity Questionnaire and considered as a continuous measure of metabolic equivalents in minutes/week (MET-min/week). Our primary exposure of interest was HIV serostatus. We fit univariable and multivariable linear regression models to estimate the relationship between HIV and PA levels, with and without addition of sociodemographic and clinical correlates of PA (MET-min/week). In secondary analyses, we explored relationships restricted to rural residents, and interactions between gender and serostatus.

Results

We enrolled 309 participants, evenly divided by serostatus and gender. The mean age of PWH was 52 [standard deviation (SD) 7.2] and 52.6 (SD 7.3) for PWOH. In general, participants engaged in high levels of PA regardless of serostatus, with 81.2% (251/309) meeting criteria for high PA. However, PWOH reported higher mean levels of PA met-minutes/week than PWH (9,128 vs 7,152, p ≤ 0.001), and a greater proportion of PWOH (88.3%; 136/154) met the criteria for high PA compared to PWH (74.2%; 115/155). In adjusted models, lower levels of PA persisted among PWH (β = -1,734, 95% CI: -2,645, -824, p ≤ 0.001). Results were similar in a sensitivity analysis limited to people living in rural areas.

Conclusion

In a rural Ugandan cohort, PWOH had higher levels of PA than PWH. Interventions that encourage PA among PWH may have a role in improving NCD risk profiles among PWH in the region.

Hypertension: Do Inflammation and Immunity Hold the Key to Solving this Epidemic?

Elevated cardiovascular risk including stroke, heart failure, and heart attack is present even after normalization of blood pressure in patients with hypertension. Underlying immune cell activation is a likely culprit. Although immune cells are important for protection against invading pathogens, their chronic overactivation may lead to tissue damage and high blood pressure. Triggers that may initiate immune activation include viral infections, autoimmunity, and lifestyle factors such as excess dietary salt. These conditions activate the immune system either directly or through their impact on the gut microbiome, which ultimately produces chronic inflammation and hypertension. T cells are central to the immune responses contributing to hypertension. They are activated in part by binding specific antigens that are presented in major histocompatibility complex molecules on professional antigen-presenting cells, and they generate repertoires of rearranged T-cell receptors. Activated T cells infiltrate tissues and produce cytokines including interleukin 17A, which promote renal and vascular dysfunction and end-organ damage leading to hypertension. In this comprehensive review, we highlight environmental, genetic, and microbial associated mechanisms contributing to both innate and adaptive immune cell activation leading to hypertension. Targeting the underlying chronic immune cell activation in hypertension has the potential to mitigate the excess cardiovascular risk associated with this common and deadly disease.