1. Introduction
Hypertension (HTN) is a worldwide epidemic, affecting one third of
adults or one billion people. (Benjamin et al., 2017; Yoon, Fryar, &
Carroll, 2015). Although much progress has been made in the treatment
of cardiovascular disease (CVD), HTN continues to be a major public
health challenge. Untreated HTN can lead to heart disease and stroke,
two of the leading causes of death in the United States (U. S.) (Benjamin
et al., 2017; CDC, 2013). Furthermore, HTN disproportionately affects
African Americans (AA) more than all other races (41.2% vs 28%, respectively) (Nwankwo, Yoon, Burt, & Gu, 2013; Yoon et al., 2015).
Despite the majority of the AA population receiving HTN
pharmacological management services, only 58% have blood pressure
(BP) control at their target levels compared to 65% of Caucasians
(Benjamin et al., 2017; Ostchega, Yoon, Hughes, & Louis, 2008). Additionally, the effects of HTN in AAs may be more severe, as AAs suffer
more co-morbidities and renal complications related to HTN than other
races, and often HTN manifests in AAs during young adulthood between the ages 18 and 39 (Aronow et al., 2011; CDC, 2013; Ferdinand,
2010; Mozaffarian et al., 2016). A number of physiological traits, environmental characteristics, and behavioral factors contribute to this
disparity, all of which contribute to outcomes of early morbidity and
mortality in the AA population (Benjamin et al., 2017; Center for
Disease Control and Prevention, 2013). Thus, to improve health
outcomes in AAs with HTN, a comprehensive approach, including
pharmacological therapy and lifestyle management is vital, along with
understanding the potential influence of other factors affecting lifestyle
management such as co-morbidities, creatinine and potassium serum
levels, education, depression, locus of control (LOC), and social support.
Evidence supports pharmacological therapy in achieving the goal of
lowering BP to improve overall health outcomes, yet lifestyle modifications are less studied. The recent 2017 HTN guidelines denote the
importance of individualized tailored approach including lifestyle
changes which addresses all CV risk factors (Greenland & Peterson,
2017). In the AA population, less is known about lifestyle behaviors and
the effect on HTN. Participation in PA decreases BP (Whelton, Chin,
Xin, & He, 2002). Unfortunately, the American College of Cardiology
and the AHA guidelines on lifestyle reported that most studies examining the effects of lifestyle changes, physical activity (PA) and diet,
have not included those with HTN (Eckel et al., 2014).
The management of HTN requires self-regulation (Chen, Tsai, & Lee,
2009). Multiple factors associated with PA participation, especially in
AAs, is essential to affect health outcomes. Factors supporting participation in PA include social support (Anderson, Wojcik, Winett, &
Williams, 2006; Gothe & Kendall, 2016; Thompson et al., 2003) and
education (Alkerwi et al., 2015; Dinwiddie, Zambrana, Doamekpor, &
Lopez, 2015). Depression also influences participation in PA and is
clearly linked to CVD (Almas et al., 2014; Rogerson, Murphy, Bird, &
Morris, 2012). While it is known that depression affects medication
adherence (Grenard et al., 2011; Schoenthaler et al., 2015) in those
with HTN, little is known about how depression affects lifestyle behavior of PA in HTN patients with high medication adherence.
Motivation, control or the ability to regulate behavior is also a
factor influencing participation and maintenance of PA (Peters &
Templin, 2008; Ryan & Deci, 2007; Teixeira, Carraça, Markland, Silva,
& Ryan, 2012). The extent to which people believe they can regulate or
have control over their own behavior, referred to as LOC, can reside
either “internal” or “external” to the individual (Wallston & Wallston,
1981). Internal LOC constitutes the belief that health is the result of
one’s own action; whereas external LOC is the premise that individual
health outcomes are controlled by others, fate, or chance. Health LOC
has been identified as a predictor of self-care adherence in individuals
with known chronic diseases such as asthma and heart failure
(Ahmedani, Peterson, Wells, Rand, & Williams, 2013; Rydlewska et al.,
2013). Therefore, determining if health LOC influences PA participation, an essential self-care management behavior for HTN, is important
in promoting lifestyles interventions to control HTN. The purpose of
this study was to examine factors associated with PA participation in
AAs with HTN who have high pharmacological optimization.
2. Methods
We used a cross-sectional descriptive correlational design for the
following research questions: (a) What proportion of AAs with HTN
demonstrate lower versus higher PA?, and (b) Do systolic BP, co-morbidities, serum levels of creatinine and potassium, education, depression, LOC, and social support explain PA participation in AAs with
HTN?
2.1. Design/sample
After approval from the institutional review board, we recruited
AAs from a clinic in the rural southeastern region of the U. S. who
recently completed the Systolic Blood Pressure Intervention Trial
(SPRINT) (The SPRINT Research Group, 2015). The SPRINT study was a
multi-center randomized clinical trial comparing the safety and efficacy
of intensive BP management to standard management. The purpose of
the study was to compare outcomes of a targeted systolic BP of < 120
mmHg to 140 mmHg (The SPRINT Research Group, 2015). Over 9000
participants were enrolled meeting the inclusion criteria of: (a)
age ≥ 50 years, (b) HTN with systolic blood pressure > 130 mmHg,
and (c) one risk factor of heart disease. Exclusion criteria for SPRINT
included a diagnosis of cancer, stroke or any known terminal illnesses.
Those enrolled in SPRINT received medication at no cost and were
closely monitored by health care providers. The trail ended early due to
lower rates of CV deaths, MI, stroke, heart failure, and acute coronary
syndrome (Berlowitz et al., 2017).
The sample of this study consisted of AAs with a diagnosis of HTN
who completed the SPRINT study. They were English speaking, and
were cognitively intact as noted on their medical record. Because this
study only enrolled AA participants who completed SPRINT in the past
the 6 to 12 month period, medication adherence was re-examined. All
eligible participants reported high adherence to their medications with
a mean of 99% in this study. This was not a surprise finding, as the
larger clinical study provided all medications and a comprehensive
team management approach. Participants meeting eligibility requirements scheduled an appointment to review the study, provide informed
consent, and complete the questionnaires. Appointments were held in
an outpatient clinic and lasted approximately 1 h.
2.2. Measures
Participants completed an investigator developed demographic
health assessment tool. Identification of who provides the most social
support was self-reported as an open-ended question. The degree of
perceived social support received was self-reported on a Likert scale
and measured as: none of the time, a little of the time, some of the time,
a good bit of the time, most of the time, and all of the time. A separate
visual analog (VAS) scale using a 0–100 mm with anchors on each end
ranging from 0 (no support) and 100 mm (support all the time) was
used to denote specific social support for PA participation. Physical
activity participation, defined as any activity that requires energy expenditure for a minimum of 30 min at least 4 times a week (Ghadieh &
Saab, 2015), was measured using a self-reported 0–100 mm visual
analog scale (VAS-PA) with anchors on each end ranging from 0 (none
of the time) to 100 mm (all of the time). The distribution of scores was
divided into quartiles to achieve the best measure of central tendency,
using the 50th percentile to designate those with high and low PA
participation. The background physiological data were retrieved and
included the current systolic BP, body mass index, and potassium and
creatinine serum levels. Co-morbidities were also retrieved, which included categories of CVD other than stroke, chronic respiratory diseases, chronic kidney disease, diabetes, and arthritis. Participants also
completed standardized instruments.
