Elevated blood pressure and illness beliefs: a cross-sectional study of emergency department patients in Jamaica

The Jamaican Health and Lifestyle survey of 2007–2008 estimated that approximately 25% of the Jamaican population aged 15–74 had high blood pressure (BP); however, only 50% were aware that they had elevated blood pressure [1–3]. For each 20 mmHg systolic or 10 mmHg diastolic increase in blood pressure (BP) above normal, there is a doubling in risk of cardiovascular, cerebrovascular, and renovascular disease [4–7].

In the USA in 2005, there were 3.3 million high BP-related emergency department (ED) visits [8]. Recent data suggest that the majority of patients with elevated BP in the ED carry a true diagnosis of hypertension (HTN) [9, 10]. In the USA and other locations worldwide, the ED often serves as the safety net for persons with chronic diseases such as HTN and may be an important location to help prevent adverse consequences associated with poor BP control [9, 11, 12].

Anecdotal evidence suggests that there are a significant number of patients who present to Jamaican EDs with elevated BP, those both with and without a prior outpatient diagnosis of HTN. The same may be true for Afro-Caribbean locations, but epidemiological data are lacking. The ED could play an important role in increasing knowledge surrounding how to achieve well-controlled HTN by providing brief education and referral [13]. The ED is often the only source of medical care for those who are underserved [14, 15]. For this reason, emergency medicine clinicians play an important role in improving population BP control [16].

This study was designed to evaluate patients who present to the ED with elevated BP in a representative Afro-Caribbean institution and to evaluate, among patients with known HTN, the relationship between elevated BP and potential contributory factors such as socioeconomic status, health-seeking behavior, and underlying HTN illness beliefs.

In this convenience sample of patients presenting to the UHWI, approximately 2 out 5 patients had an elevated BP in the emergency department, more than the previously reported 1 out of 5 among American patients primarily of African American descent [9]. Moreover, among those with a previous diagnosis of HTN, BP was elevated in more than 60%. Although these data were derived from a cross-sectional sample in an emergency setting, they suggest that a large number of individuals presenting to the ED have elevated systolic blood pressure with an underlying diagnosis of HTN—more than would be expected based on other population-level surveys conducted in the general Jamaican population [2, 8].

Those with a diagnosis of HTN did not differ in their illness beliefs whether they had normal or elevated presenting BP in the ED. These findings conflict with previous studies reporting negative illness beliefs among those with poorly controlled BPs [20, 21]. Pickett et al. [21] evaluated a cohort of 111 outpatient African American patients and noted that patients with poor disease understanding had poorly controlled BPs. Moreover, we found no difference in reported medication self-efficacy among hypertensives with elevated BPs compared to those with normal BPs. A review of the literature reveals a mostly negative correlation, regarding the relationship between disease understanding and medication self-efficacy and the impact on BP control among some populations [22–25].

This disparity between our findings and that previously discussed in the literature may be secondary to this populations’ rote knowledge, but not a true understanding of the disease and importance of BP control. Notably, the majority of these studies evaluating illness beliefs were conducted in an outpatient non-emergent setting. Financial insecurity may also account for this incongruence between disease beliefs and medication self-efficacy [26, 27]. Even so, there was no significant discrepancy between incomes among those presenting with elevated BP compared to those presenting with normal BP. However, our findings that education level is associated with BP control underscores the previously identified association between low literacy rates and elevated ED BP [11, 24, 28]. The ED could play an important role in increasing knowledge surrounding how to achieve well-controlled HTN by providing brief education and referral [13].

While this study provides important, previously understudied, epidemiological information about patients who present to the ED with elevated BP in Jamaica, there are several limitations. We used a cross-sectional design with convenience sampling. We attempted to overcome this by capturing patients presenting to the ED during all times and in all areas of the department; however, based on the sampling methodology, our findings might not be generalizable to the overall ED population. We used previously validated survey tools on illness beliefs and medication adherence self-efficacy, but the validation was not done in an Afro-Caribbean population and these scales may not accurately reflect true perspectives of our target population [17, 18]. Because of interview time constraints, we captured only the illness beliefs of those patients presenting with a previous diagnosis of hypertension. Future studies with larger sample sizes that enroll patients presenting to academic as well as local community hospitals would be of value. Additionally, for simplicity, we did not use a diastolic BP cutoff to define elevated BP; therefore, our estimates of elevated BP frequency may be lower than the true estimate.

In this single-center study, two of every five Jamaican patients have an elevated BP at ED presentation. Among those with a history of HTN, 60% had an elevated presenting BP. The ED can be an important location to identify patients with chronic disease in need of greater disease-specific education. Those with lower levels of education may be a particularly important population to target. Future studies should evaluate if brief interventions provided by ED medical staff improve HTN control in this patient population.