Factors associated with the use of complementary and alternative therapies among patients with hypertension and type 2 diabetes mellitus in Western Jamaica: a cross-sectional study

Hypertension (HTN) and Type 2 Diabetes Mellitus (T2DM) are major health problems globally. HTN is one of the most common non-communicable diseases, affecting up to 20% of the world’s adult population [1]. It was estimated that in 2017, 424 million people worldwide were suffering from Diabetes Mellitus (DM), with 50% undiagnosed and believed to be unaware of their illness [2]. The prevalence of DM is projected to rise to 628 million by 2045 [2]. T2DM accounts for 90% of cases of DM, and chronically affected patients can suffer from retinopathy, nephropathy, neuropathy, HTN, dyslipidemia, myocardial infarction, and stroke [3].

Several types of complementary and alternative medicines (CAM) are used worldwide for the treatment of HTN and T2DM. CAM is defined as “practices, approaches, knowledge, and beliefs that incorporate plant, animal and mineral-based medicines, spiritual therapies, manual techniques, and exercise” [4]. Individuals may choose an alternative or “natural” medical treatment because of beliefs or negative experiences with the mainstream medical community, lack of success with prescribed medicine, influence from friends and family, or negative experiences with healthcare providers (HCPs) [5]. In addition, CAM may be more easily accessible and less expensive than prescription medications [5]. Previous research shows that up to 80% of people living with T2DM use CAM. CAM use varied from 24% in the United Kingdom to 80% in Africa [6]. Most diabetic patients commonly use herbal medicine, nutritional supplements, diet modifications, spiritual healing, and relaxation techniques [4]. Despite the widespread use, a high proportion of patients might not disclose CAM use to their HCPs [7].

HTN has become a growing major public health problem for Caribbean countries in this century, with prevalence rates ranging from 26% for those over 25 years, and up to 55% for those over 40 years [8]. Half of the population aged ≥60 years is estimated to be living with HTN in Latin America and the Caribbean. People of black racial origin are at higher risk for developing HTN; therefore, Caribbean countries with predominately black populations, such as Jamaica and Barbados have higher prevalence rates of HTN [9]. In Jamaica, the estimated prevalence rate of HTN for persons aged 15–74 years is 25% [9]. Females were shown to be three times more likely to develop HTN than males and obese individuals were four times more likely to develop HTN than those with normal weight [10]. Other risk factors for HTN include: increasing age, family history of HTN, nutritional intake, salt intake, chronic stress, physical activity, and T2DM [9, 10].

T2DM has become an increasing problem in Latin America and the Caribbean in recent years, with certain Latin American countries having some of the highest prevalence rates globally [11]. In 2017, the total number of diagnosed cases of T2DM among adults 20–79 years in Jamaica was 209,300 [12]. The rate of T2DM cases increases with age. In 2015, Jamaicans aged 55–79-years had prevalence rates of T2DM ranging between 20 and 30%; those aged 20–34 years had prevalence rates of only 3–7% [12]. The cost of DM-related health care for adults in Latin America and Caribbean countries in 2000 was estimated at 65 billion United States Dollars (USD) [13]. Modifications in lifestyle such as exercise, weight loss, proper nutrition, and a low-fat diet are important in the management of T2DM.

“Bush” or herbal medicine use in the Caribbean is well documented. Herbs are widely used in treating conditions ranging from the common cold to chronic conditions such as HTN and T2DM [14‐16]. Jamaican history shows that there has been a very high reliance on using medicinal plants as treatments for ailments [17]. A study conducted among black Caribbean patients found that 72.6% of participants reported regular use of herbal medicine to treat an illness or maintain good health in the past 12 months [15]. Of those who reported herbal medicine use, 77% reported using herbal medicine to treat respiratory illnesses and 53% to treat gastrointestinal problems [15]. Smaller percentages of participants reported the use of herbal treatments for HTN (15%) and T2DM (4%) [15]. Another study that examined the use of bush medicine in Trinidad and Tobago found that 42% of participants reported using herbs, and 24% reported using herbs for T2DM [16]. A study conducted in Jamaica in 2006 on the concomitant use of prescription medicines and herbs for a variety of ailments found that 83.2 and 79.5% of participants practiced concomitant herb-prescription medicine use for DM and HTN, respectively [18].

However, recent scientific literature on the use of CAM in the treatment of HTN and T2DM from the Caribbean, and Jamaica in particular, is sparse. Therefore, we conducted this research to investigate CAM use among patients diagnosed with HTN and T2DM in western Jamaica. We investigated associations between knowledge and perceptions of CAM and CAM use among the patients. The findings from this study can be used in the development of educational interventions that promote the appropriate use, and mitigate detrimental effects, of CAM in treating HTN and T2DM.

This study describes the prevalence and factors associated with CAM use by patients for treatment of HTN and T2DM in western Jamaica. More than one-quarter (28%) of the patients had both HTN and T2DM. HTN and T2DM frequently coexist, leading to increase in the risk of life-threatening complications. The high proportion of females (76.5%) in the study can be explained by the fact that females are a high-risk group for developing HTN in Jamaica. Previous research in Jamaica suggests that females are three times more likely to develop HTN compared to males [10]. Thus, our enrollment of 76.5% females exactly matches this reported prevalence.

Our finding of a high prevalence of CAM use among patients with both HTN and T2DM is consistent with that of a study that reported herbal medicine to treat ailments and maintain health by 72.6% of Jamaicans [15]. Our results are also consistent with the findings of some studies conducted globally that show CAM usage of 17–80%, with the highest rates in Africa [6]. The reason for the high use of herbal medicine in Jamaica could be attributed to the fact that herbs are a part of the daily lives of many Jamaicans since they are often consumed as tea [19]. However, the increased interest, belief, and use of CAM in Jamaica in the mid-late 1990s, and Jamaica’s poor economic situation, may have helped to facilitate the increased use of herbs [20, 21]. The medications associated with the treatment for HTN and T2DM are lengthy and costly. The study by Delgoda et al., found that those of high socioeconomic status and those with health insurance had much lower use of combined herb and prescription medication, further strengthening the idea that the boom in herbal use was in part due to financial reasons [18].

In this study, over 60% of participants with T2DM and 70% with HTN used CAM simultaneously with prescription medicine. A previous study found that almost 80% of patients with HTN and 83% with T2DM practiced concomitant use of CAM and prescription drugs; 94% of respondents believed that there was no harm in taking CAM and prescription medication concomitantly [18]. Over two-thirds of participants in our study said that it was unacceptable to use prescription medicine and CAM simultaneously. However, patients with T2DM who believed that simultaneous use of CAM and prescription medicine was acceptable were seven times more likely to use CAM, and patients with HTN who believed that CAM is a natural method for treating disease were almost 4 times more likely to use CAM. These findings clearly show that patients’ beliefs regarding CAM strongly determine their use CAM and point to the need for appropriate counseling on the use of CAM, especially along with prescription medication, in order to mitigate possible harmful effects of simultaneous use of CAM and prescription medicine. For example, garlic (Allium sativum) which is commonly used in Jamaica to treat HTN and T2DM, has been shown to have antihypertensive, hypoglycemic, and lipid-lowering properties and therefore could cause adverse health effects if taken simultaneously with prescribed medication for HTN and T2DM [22, 23].

In the current study, self-reported knowledge of CAM was significantly associated with CAM use among patients with HTN and T2DM. In both groups, patients who reported that they had no/poor knowledge of CAM were significantly less likely to use CAM than those who reported average/good/excellent knowledge of CAM. Thus, use of CAM by patients seems to be driven by confidence regarding knowledge of CAM. Future studies should assess self-reported knowledge compared with tested knowledge of CAM among participants. This would allow identification of misconceptions regarding CAM and for educational interventions that provide accurate information on CAM to be developed and conducted. In addition to educational interventions on CAM, increasing resources within communities for easy access to routine blood pressure checks and blood glucose readings will help patients to monitor their blood pressure and blood glucose levels frequently. This could help them to understand their illness and document the effects of prescription medicine in controlling their HTN and/or T2DM.

The gap in patient-HCP dialogue regarding CAM use is of particular concern. Only about 20% of our participants reported that they discussed CAM use with their HCPs. Other studies report that only 18–19% of medical practitioners are aware of herbal use by their patients [8, 24]. This gap in communication between patients and HCPs may be attributed to the fact that many patients expect negative reactions from HCPs about their use of CAM and prefer not to disclose such information [15]. On the other hand, this lack of communication could occur because HCPs do not ask patients about their CAM use [2]. The Jamaican study by Delgoda et al., reported that only 11.3% of participants who used herbs were asked about CAM use by their doctors. Our results indicate that among the participants who used CAM, only 19–20% reported that they had received information about CAM from their HCP.

In accordance with the World Health Organization (WHO) 2008 Beijing Declaration, which promotes the safe and effective use of herbal remedies, there is a need for more publicly available information regarding the safe use of herbal remedies [24]. In order to promote appropriate knowledge of CAM in Jamaica, there is need for collaboration between the Ministry of Health and health educational institutions (schools of nursing, medicine, nutrition, pharmacy and public health) on training in CAM and communication with patients.

Regardless of the limitations, this study identified factors such as self-reported knowledge of CAM, belief that CAM is a natural method for treating HTN, and belief that it is acceptable to use CAM and prescription medication simultaneously to treat T2DM, to be significantly associated with CAM use. These findings strongly suggest the need for educational interventions for both patients and HCPs to address the gaps in knowledge and communication of CAM and to ensure proper use of CAM in treating HTN and T2DM. This is important for the appropriate management of these major debilitating diseases in the Jamaican society.