Dissertations and Theses

Date of Degree

10-21-2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Epidemiology and Biostatistics

Advisor(s)

Denis Nash

Committee Members

Jennifer Dowd

Daniel Fitzgerald

Margaret McNairy

Robert Peck

Subject Categories

Epidemiology | Public Health

Keywords

hypertension, HIV, antiretroviral treatment (ART), slum, Haiti

Abstract

Background: Rapidly growing urban slum settings increasingly face co-occurring communicable and non-communicable health crises, against the backdrop of extreme poverty, and social and environmental vulnerability. In Haiti, sparse data suggest a growing burden of hypertension and cardiovascular disease (CVD), along with substantial prevalence of HIV, increasingly recognized as a major CVD risk factor. As life-saving antiretroviral treatment (ART) is extended to more people living with HIV (PLWH), their risk of CVD increases with longer life expectancy and possibly cumulative ART exposure. Pregnant HIV-positive women may face additional cardiovascular vulnerability, due to the risk of gestational hypertension and pre-eclampsia. Integration of hypertension and broader non-communicable disease (NCD) services is increasingly recommended and piloted in vertical HIV programs, though often complicated by challenges with facility preparedness. The goal of this dissertation was to examine the burden and patterns of hypertension, as well as related healthcare needs, among slum community residents and PLWH receiving standard HIV care services at a clinic serving large slum communities in Port-au-Prince, Haiti.

Methods: This work utilizes cross-sectional primary data from a population-representative community survey (aim 1) and longitudinal secondary data from the electronic medical records of a local HIV clinic (aims 2 and 3), altogether spanning the period from 2007 to 2017. In aim 1, data from a multistage randomized survey were used to characterize the prevalence, correlates, and care continuum of hypertension among residents of four slum communities in Port-au-Prince. In aim 2, hypertension prevalence, incidence, and patterns following onset were examined among newly diagnosed with HIV patients initiating ART at a local HIV clinic. In aim 3, trends in the prevalence and incidence of gestational and chronic hypertension, and longitudinal blood pressure trajectories, were assessed among HIV-positive pregnant women with and without prior ART exposure in a prevention-of-maternal-to-child-transmission (PMTCT) program.

Results: In aim 1, among adult slum community residents with a median age of 28 years, 20% screened positive for hypertension using a single-day blood pressure measurement, with overweight and obesity being the most common risk factor (21% among men and 49% among women), and a low prevalence of smoking (12% among men and 4% among women). Individual’s odds of hypertension rose with hypertension prevalence in immediate surroundings. Four out of ten persons with hypertension on the day of the survey had been previously told by a clinician that they had the condition, but fewer than one in ten reported receiving treatment.

In aims 2 and 3, the gold standard two-day definition of hypertension was applied. In aim 2, among newly diagnosed with HIV persons with a median age of 37 years, and relatively low prevalence of overweight and obesity (16%), 12% of patients had hypertension at enrollment and among those initially hypertension-free, 19% developed hypertension within the first 18 months of HIV care and treatment. While patients with lowest enrollment CD4 counts (≤ 100 cells/µl) at enrollment had lower hypertension prevalence (8%), they were at a greater risk of hypertension incidence than patients with higher CD4 counts (15 versus 10 per 100 person-years of follow-up). Following onset, 44% of patients had hypertension on half or more of the subsequent measurements over a median of 24 months of follow-up. Patients with initial stage 1 hypertension and younger patients were less likely to maintain hypertensive status during follow-up.

In aim 3, threefold increases in the rates of chronic and gestational hypertension were observed over time among pregnant women (median age of 29 years) enrolled in a PMTCT program between 2007 and 2016. In the most recent period, 2013-2016, 4% of pregnancies were affected by chronic hypertension and another 7% - by gestational hypertension. Increased duration of prior ART exposure was strongly associated with higher latent class model-derived trajectories of mean arterial pressure (MAP), a possible risk factor for pre-eclampsia. In multinomial regression, pregnancies among women with more than a year of prior ART had almost three times the adjusted odds of a higher MAP trajectory as pregnancies without prior ART exposure.

Discussion: The findings highlight the potential for continued growth in the hypertension and CVD burden in Haiti, as well as unmet need for prevention, screening, and quality treatment services, among both the general urban population and among HIV patients specifically. In addition to secular trends in these conditions, the increase in cumulative exposure to ART might further fuel the rise in hypertension and CVD in settings with high prevalence of HIV, such as urban Haiti. Further research is needed into multimodal interventions and facility- and community-based long-term care models, increasingly for multimorbidity, among mobile urban slum community residents, with consideration of possible network effects. Quality of hypertension screening is also of importance, as white-coat and masked hypertension, as well as potential measurement error and natural blood pressure variability, may complicate the identification of true cases, in particular on the lower part of the age spectrum. Facility- and community-based programs have an opportunity to meaningfully improve individual and population health through expanding existing HIV services to encompass hypertension and broader NCD care, and through leveraging community health workers to reach families and networks in need of prevention, screening, and management services.

Available for download on Thursday, December 15, 2022

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