In this systematic review on people’s perspectives on hypertension and drug taking, many participants in the individual studies perceived stress to be the primary cause and exacerbating factor of hypertension. They widely described symptoms they perceived to be caused by hypertension, particularly headache, palpitations, and dizziness. Contrary to the conclusions of individual studies, these symptoms were consistent among different ethnic and geographical groups. Notably, these symptoms are also commonly reported as being caused by anxiety in the biomedical literature.77
Participants intentionally adjusted their drug dose, took drugs sporadically, and stopped altogether, often without consulting their doctor. Reasons given for reducing treatment included a perception that blood pressure had improved because of a reduction in symptoms, that drugs were unnecessary when under less stress, a dislike of taking drugs, a fear of addiction or tolerance, and side effects.
Comparison with other research on health understanding
A systematic review in 2005 included 37 qualitative studies looking at drug taking in any medical condition (including four hypertension studies also reported in this review).8
That review also found that drugs were seen as undesirable and that many participants feared dependence and tolerance. Participants often tested new drugs for a time to check for adverse effects and whether symptoms were reduced. Our review provides confirmatory evidence from a larger number of studies that these themes are important in hypertension and adds further themes important in hypertension specifically, particularly around stress and symptoms.
Quantitative research provides some evidence that the themes presented here are widespread. A UK study found that 43% of people used complementary medicine to treat hypertension.78
Two US studies found that most participants had symptoms they believed to be caused by hypertension (71-94% in the first study, 70% in the second study).79
Comparison with biomedical model
Stress and symptoms
The nature of the connection between hypertension and stress has been researched extensively. Acute stress has been shown to temporarily increase blood pressure levels.81
Evidence from observational studies has also shown that chronic stress can be associated with a sustained rise in high blood pressure.82
In the medical literature, however, stress is considered in the context of other important risk factors for hypertension, both modifiable and non-modifiable: age, ethnicity, family history, obesity, a sedentary lifestyle, and alcohol and salt intake.1
While participants in our review widely reported avoiding stressful situations, a meta-analysis of randomised controlled trials of relaxation interventions for people with hypertension found that they did not substantially improve blood pressure levels, nor did the trials find good evidence of an effect on cardiovascular disease or mortality.83
From the medical perspective, stress plays a small part in hypertension, whereas a recurring theme in the studies presented here was that stress was by far the most important cause.
Likewise, the biomedical literature suggests that symptoms are more likely to be connected with anxiety and stress than blood pressure itself. Although people with hypertension in observational studies have been found to report symptoms, these studies also found that symptoms did not coincide with periods of raised blood pressure when measured clinically.84
It was also found that these symptoms were significantly more likely in anxious people. A larger study in the general population found the same association with nervousness, but also found no link with periods of high blood pressure.86
Benefits and adverse effects
Side effects were a widely reported reason for self adjusting or stopping drugs. Participants in these studies described a range of adverse effects of treatment, many of which are listed in the medical literature, including leg swelling, urinary frequency, fatigue, and impotence.87
Other longer term fears about the drugs, such as the perception of addiction “building up” over time, or acting as sedatives, are not present in the medical literature. A fear of addiction is not exclusive to hypertension: qualitative studies have found that participants with other chronic medical problems reported identical views.8
Conversely, participants in several studies in this review reported seeing treatment as essential, stating they would not contemplate missing even a single day. The responses from some participants suggest they thought that treatment abolished any risk of cardiovascular disease.33
The benefit assumed by these participants is much greater than the small absolute reductions in risk found in clinical trials.90
Overlap with biomedical model
Rather than being entirely separate, participants’ understandings of hypertension overlapped with many aspects of the biomedical model. Aside from the universally strong emphasis placed on stress, the causes and consequences of hypertension reported by participants are identical to those in any medical textbook. The largest included study examined this contradiction in more depth.24
In this study individual participants often held mutually contradictory explanations, and the inconsistencies did not trouble them.
Similarities among cultural, ethnic, and geographical groups
Previous studies have examined the health beliefs of specific ethnic groups; in particular, many have been done in African-American people, to explore cultural factors influencing low rates of hypertension control.91
The authors of many of the studies in this review concluded that specific culturally appropriate education is needed, implying that their findings were unique in the particular population studied. However, the principal themes identified here were remarkably similar across geographical and ethnic groups. Participants in most of the studies perceived hypertension as a symptomatic illness associated principally with stress; this was confirmed in the sensitivity analyses looking at studies that were not restricted to minority ethnic groups, and in the non-US studies.
Differences between cultural, ethnic, and geographical groups
Racism was often reported by participants from minority ethnic groups. In several studies from the United States of African Americans and one of Filipino-Americans and one study of people of black Caribbean ethnicity in the United Kingdom, the stress caused by racism was reported to exacerbate hypertension. Migrant populations also perceived that they were more likely to have low paying jobs and experience greater economic hardship. African-American participants from two US studies reported a lack of trust of their white doctors, perceiving prejudice against them.
A UK study that compared the reports from black Caribbean and white British participants found that a large number of black Caribbean participants reported self adjusting and stopping drugs, whereas all but one white British participant reported taking drugs regularly. Although a traditional diet was mentioned as an exacerbating factor for hypertension in many studies, this did not seem to be unique to any particular group. A Dutch study found that people of Surinamese, Ghanaian, and white European ethnicity equally thought that their traditional diet worsened their blood pressure.22
Implications for clinicians and hypertension education
The evidence presented here adds weight to the criticism of educational interventions that assume poor adherence is due to patients’ failings, either in knowledge or remembering to take drugs.92
The participants in the studies presented here did not simply have a knowledge deficit but held alternative explanations for their hypertension; many deliberately chose to avoid drugs.
This may explain why educational interventions that simply inform about the conventional medical view have proved ineffective.9
To better deal with these problems, clinicians and educational interventions must acknowledge and incorporate patients’ concerns and perspectives. Specifically, patients should be given an honest and accurate representation of the likelihood of benefit and adverse effects with treatment. The evidence of safety of long term use of drugs should be discussed, including that treatment is not thought to “build up” in the body or to cause a physical dependence. Fears about addiction could be further tackled by informing patients that they are unlikely to experience adverse effects if they decide to stop, no matter how long they have taken the treatment. This is in stark contrast to existing educational interventions, which emphasise the importance of continuous tablet taking.9
Rather than denying the possibility of symptoms, patients’ experiences should be acknowledged. Patients could be informed that people with hypertension often report symptoms but that they have not been found to be a reliable indication of fluctuations in blood pressure levels. Patients could be informed that their risk of cardiovascular disease is increased regardless of whether they have symptoms, and that treatment can effectively prevent cardiovascular disease.
Stress should be placed in the context of other modifiable and non-modifiable risk factors for hypertension and cardiovascular disease; it should be noted that relieving stress alone is not likely to normalise blood pressure and that treatment is recommended at times of high and low stress.
Non-intentional factors, such as forgetting and being busy, were mentioned by many participants as reasons for not taking drugs, and there is low quality evidence from randomised controlled trials that reminder interventions may have an effect.9
However, the qualitative research suggests that reminders alone that neglect patients’ health understanding are not likely to provide a highly effective solution.
Finally, we did not find strong evidence that educational interventions for hypertension need to be tailored to a particular cultural or ethnic group; the consistency of the results presented here suggests that it is more important to take account of common understandings and experiences across the world.
Strengths and weaknesses of the review
This study used a systematic strategy for identifying, reporting, and synthesising qualitative research. Several features suggest that the results are robust. Firstly, we identified a large number of studies, which were largely judged to be of high quality. Secondly, many of the themes we identified were reported repeatedly in a large number of papers. These themes did not vary substantially across different countries. Thirdly, the results of sensitivity analyses, when we removed the groups of papers thought possible to cause bias, did not change the conclusions of the main analysis.
We chose to use the Economic and Social Research Council guidance on narrative synthesis as it both encourages transparent reporting and places a strong emphasis on assessing the robustness of results; the lack of both has been a criticism of other methods of synthesising qualitative research.93
Although no formal test of different synthesis methods versus each other exists,93
the strong evidence of themes found here and the large degree of overlap between narrative synthesis and other qualitative synthesis methodologies suggest that other methods would have produced similar results.
We made a pragmatic decision to include studies from peer reviewed journals only, to retrieve the highest quality research. It seems likely that a body of qualitative research also exists in book chapters, university theses, and conference presentations, that was not included in this review. Although we used no language restriction for inclusion of studies and included some non-English language papers, we would have missed those not listed on English language databases.
Certain groups in the research were represented disproportionately: nearly half of the studies looked at an ethnic minority population and nearly half were done in the United States. Although this presented a potential source of bias, the themes in these papers did not differ substantially from those from other countries and from studies without restriction to an ethnic group.
Implications for research
This review examined the importance of patients’ health understanding for one aspect of cardiovascular disease prevention. Syntheses of the qualitative research on other cardiovascular risk factors would complement the findings and could help inform the development of new interventions. Carrying out a systematic review when planning new qualitative research may help to avoid the unintentional examination of questions that have already been extensively researched. Finally, when developing future educational interventions, it may be more rewarding for researchers to consider shared explanations for hypertension rather than attempting to target a specific ethnic or cultural group.
Implications for practice
Lay perspectives about hypertension are often different from the medical viewpoint: worldwide, people widely perceive that hypertension is principally a stress related condition with symptoms and fear addiction or dependence on drugs. These commonly caused people to reduce or stop treatment. If they are to be successful at improving adherence, future educational interventions must incorporate and engage with these widespread perspectives and experiences rather than simply reiterating the biomedical view. A greater understanding between doctors and their patients must play a part in future strategies for reducing cardiovascular disease.
What is already known on this topic
- Between 30% and 50% of people with hypertension do not take drugs regularly
- Qualitative research in other chronic conditions showed that patients often actively decide to avoid drugs rather than unintentionally missing them
- Qualitative studies have focused on the health beliefs of specific ethnic groups in hypertension, suggesting that cultural factors contribute to low rates of control
What this study adds
- People with hypertension interviewed in qualitative studies often relied on the presence of stress or symptoms to determine whether their blood pressure was raised
- This perceived connection led many to reduce or stop drugs in response to fewer symptoms or less stress
- There seem to be few major differences in understanding of hypertension between people from different ethnic groups and countries—calls for culturally specific education by the authors of qualitative studies may not be justified