Substituting Lifestyle Management for
Pharmacological Control of Blood Pressure:
A Pilot Study in Australian General PracticeThis section is compiled by Frank M. Painter, D.C.
Send all comments or additions to: Frankp@chiro.org
FROM: Blood Press 2000; 9 (5): 267–274
Reid CM, Maher T, Jennings GL; Heart Project Steering Committee
Alfred and Baker Medical Unit,
Baker Medical Research Institute,
Melbourne, Australia.
chris.reid@baker.edu.auThe HEART project was conducted in general practice to determine whether lifestyle strategies, aimed at increasing physical activity and dietary modification, can be substituted for drug therapy in patients who have been well controlled on antihypertensive medication. In addition to blood pressure (BP) and risk factor outcomes, lifestyle behaviours, quality of life of patients, and the acceptability of the approach to both general practitioners (GPs) and patients involved in the trial were assessed. Patients (n = 45) with a history of hypertension and who had been well controlled for at least the past 6 months (BP < 160/ 95 mmHg) were randomised to a continued medication (C) group (n = 24) or a withdrawal (W) group (n = 21). Subjects had received antihypertensive therapy for an average of 7.8 years (range 1–28 years). Drug therapy in the W group was recommenced if BP exceeded 160/95 mmHg on two consecutive visits. Both groups were counselled regarding lifestyle behaviour change by their GP throughout the study and were provided with specifically developed self-help materials. Subjects were reviewed at least monthly over a 9–month period. Following randomisation, there were no significant differences between the two groups for BP, heart rate, age, duration of therapy, total cholesterol or body mass index. All but three subjects (one from the W and two from the C group) completed 9 months of monitoring following randomisation and there were no cardiovascular events; 71% of subjects remained off drug therapy and were well controlled at the 9–month follow-up (15/21) with mean BP of 141/85 mmHg (W) and 139/ 86 mmHg (C). Systolic BP tended to increase during the study period in both W and C groups, however, no significant differences were observed in mean systolic or diastolic BP either between the two groups or within each group in comparison to baseline values. Resting heart rate, body mass index and cholesterol levels remained unchanged in both W and C groups after 9 months follow-up. There were no changes attributable to the lifestyle intervention in the subjects continuing drug therapy in BP or lifestyle variables over the study period. However, the group stopping therapy had a 6% reduction in body mass index after 9 months. These data suggest that a proportion of motivated patients willing to trial a lifestyle approach can cease drug therapy and be adequately maintained by the prescription of lifestyle advice via their GP for at least a 9–month period. Cessation of drug therapy may be an important motivating factor to achieve weight loss in this group.
From the FULL TEXT Article:
INTRODUCTION
Hypertension is the most common medical condition requiring long-term drug therapy in Australia. [1] Evidence accumulated over the last 20 years suggests that drug treatment of hypertension reduces cardiovascular mortality and morbidity. [2–4] However, when the results of treatment are compared with the expected benefits predicted by the long-term follow-up studies that identified major cardiovascular risk factors, there are some discrepancies. [5] Whereas treatment of hypertension with drug therapy appears to achieve the expected benefit in terms of reduction in stroke morbidity and mortality, the atherosclerotic complications are not reduced to the same extent. [5–7] Many reasons have been put forward to account for this including potential adverse effects of the drugs used to treat hypertension on other risk factors for atherosclerosis which might attenuate the benefits of lowering blood pressure on overall cardiovascular risk. [8, 9]
Over the last 10 years a number of randomised controlled trials have demonstrated the relative efficacy of non-pharmacological measures for lowering blood pressure. Rigorous studies have demonstrated the efficacy of a number of modalities, particularly weight loss in the obese [10, 11], regular exercise in the sedentary [12, 13], alcohol moderation [14, 15], other dietary measures including salt restriction, vegetarianism and possible alterations in fat intake. [16–18]
A potential advantage of non-pharmacological therapy is that whereas some drugs such as beta-adrenergic antagonists and diuretics adversely effect other risk factors, some non-pharmacological measures particularly weight loss and exercise training not only lower blood pressure, but also improve other risk factors. [12, 19] Therefore for a given antihypertensive effect, it is clear that different forms of therapy may differ in their effects on overall cardiovascular risk.
The present study is based on the hypothesis that sustained normotension may be possible following a long period of effective antihypertensive therapy by substituting non-pharmacological or lifestyle measures. Effective long-term drug therapy may lead to the regression of vascular wall thickening and left ventricular hypertrophy associated with sustained hypertension. The reversal of these structural changes has been reported, in both animal and human studies, to be associated with the maintenance of normotension after drug therapy withdrawal. [20, 21] Thus, maintenance of normotension may be possible with milder form of therapy such as non-pharmacological interventions.
Since the early 1960s, many studies of the withdrawal of antihypertensive drug medication following control of blood pressure have been undertaken. Most of the early observational studies showed that while blood pressure levels increased in most patients withdrawn from therapy, some (6–30%) sustained normotension for extended periods. [22–26] The previous studies differ markedly in subject inclusion criteria including the aetiology of the hypertension, duration of blood pressure therapy, level of pre-treatment and treated blood pressure and the level of blood pressure when therapy was recommenced. However, most of these studies have been conducted in the specialist clinic setting, which does not reflect the general practice setting for the management of hypertension in the 1990s.
Thus, the major aim of the present study was to examine whether non-pharmacological treatment strategies can reach therapeutic targets for blood pressure control as effectively as conventional drug-based strategies following treatment withdrawal in a general practice setting
METHODS
Study location
The study was conducted in the Footscray/Spotswood area of Melbourne’s western suburbs, which has been consistently identified as a low socio-economic area. The study was conducted within community-based general practice settings.
GPs working in the area were identified through lists provided by the Royal Australian College of General Practitioners. GPs were recruited to the project through an introductory letter explaining the aims/objectives of the programme and the general structure of the study plan. Interested GPs received a follow-up interview with the Project Medical Coordinator involving a detailed explanation of methods and study requirements on the part of the participating general practitioner. Of 67 GPs approached, 38 agreed to participate in the project with 13 GPs identifying and recruiting patients into the trial.
Subjects
GPs identified current practice patients aged 18–60 years who satisfied the major inclusion criteria of being primary hypertensives well controlled on drug therapy (systolic blood pressure 160 mmHg and/or diastolic blood pressure 95 mmHg on the previous two visits to the GP) for at least 6 months. The original diagnosis of hypertension had been according to the usual practice of the GP. Patients were provided with a brochure and were asked to make an appointment to speak to the GP regarding the project if they were interested. Patients with pre-existing cardiovascular disease (history of ischaemic heart disease, previous myocardial infarction, stroke), secondary hypertension, renal disease or any contraindication to antihypertensive drug treatment withdrawal (e.g. arrhythmia) were excluded. Subjects were fully advised of possible side-effects of ceasing medication and only those who expressed willingness to participate in a trial of drug treatment withdrawal provided written informed consent. The study was conducted with ethics approval from the Royal Australian College of General Practitioners.
Study design
Subjects participated in a 2–week run-in period to establish baseline blood pressure and to familiarise themselves with the project requirements. Subjects were then randomised to a drug withdrawal (W) or continued medication (C) group. In both groups, subjects were provided with written self-help materials and advice from their GP to aid in the establishment of lifestyle changes that will assist in the control of blood pressure. Randomisation was achieved through the allocation of sealed envelopes to practitioners and group membership was identified following the receipt of informed consent. This design has the advantage of controlling for the personality and enthusiasm of the practitioners’ approach to the use of lifestyle therapy.
In the W group, drugs were stopped over a 2–week period following a predetermined step-own protocol of half dose/half frequency after the first week. This regimen varied according to the number and type of antihypertensive medication withdrawn. Subjects were closely monitored, weekly during drug withdrawal and monthly over the remaining 9–month study period for adverse effects and control of blood pressure. Drug therapy was reinstituted if blood pressure was recorded at a level of 160/95 mmHg and confirmed with a follow-up measurement taken during the next week.
Lifestyle intervention
The behaviour change model described by Prochaska and diClemente formed the basis of the lifestyle change approach. [27] Dietary intake and regular exercise were the major lifestyle behaviours targeted. GPs were provided with information booklets outlining the behaviour change process and the stage-of-change model. Tips and suggestions on how to identify the appropriate stage-of-change for each individual and how to assist patients progress towards sustained maintenance of an adopted behaviour were provided.
The concept of hypertension management being a joint relationship between the patient, doctor and community-based support facilities was promoted. To this end, local community health and support facilities were identified as additional sources of assistance and to provide social support for patients in the action and maintenance phase of behaviour change. Local pharmacists were also involved as a source of information and support for patients withdrawing from medication.
Patient self-help booklets on exercise and good eating were produced following a review of self-help materials that identified the need for user-friendly, easy-to-read stand-alone materials for good eating and exercise. [28] The materials were pre-tested with patients prior to implementation and were favourably received. [29] The booklets were sectioned into stage-of-change components with the GP directing the patient to the appropriate section. Achievable short-term goals were discussed along with the long-term aim of the project. Qualitative analysis, using focus group methodology for GPs and individual patient interviews, were conducted to determine the attitudes and perceptions of GPs and patients to the concept of drug withdrawal and lifestyle counselling. All interviews and focus groups were audio taped and thematically analysed. [30]
Measurements
Blood pressure was measured by the GP on every clinic visit. The protocol required two recordings ofseated blood pressure to be made after a minimum of 5 min rest. Phase 5 sounds were used to indicate diastolic blood pressure. The average of the two measures was recorded as the subjects blood pressure. To assist the measurement validity, sphygmomanometers of each GP were calibrated at the commencement and at 3–month intervals during the study.
At baseline, 3–month and 9–month follow-up visits, height and weight were recorded with the subject in light clothing and stockinged feet. A fasting blood sample was collected for the assessment of total blood cholesterol, blood glucose and triglyceride, and a lifestyle questionnaire was administered. The questionnaire provided information related to dietary fat intake [31], cigarette smoking, exercise habits and alcohol intake. A general health and quality of life questionnaire, designed for use in general practice, was administered which provided scores related to physical, mental, social and general health. [32] Current medication use and drug treatment were recorded at the same time using the subject’s medical records and questionnaire.
Statistical analysis
Between group comparisons of blood pressure and other continuous variables were made using a two-way repeated measures analysis of variance [33]. Within group changes and a comparison of baseline characteristics were assessed using one way analysis of variance. Lifestyle questionnaire and quality of life responses between the two groups were compared using w2 analysis. Multiple regression analyses were used to determine any association of changes in physical activity, alcohol and dietary intake with risk factor changes. The study was designed to have an 80% probability of detecting a 10–mmHg difference in systolic blood pressure between the two groups with a two-sided significance level (alpha) of 0.05.
DISCUSSION
The major finding from the present study was that 71% of patients who had been well controlled on antihypertensive medication for a period in excess of 7 years were able to remain normotensive and free of therapy for 9 months following drug withdrawal. This is a finding consistent with results from previous studies that suggest that a proportion of patients can remain off drug therapy and sustain normotension for extended periods. Subjects who returned to therapy over the 36 weeks had higher baseline blood pressure than those remaining normotensive. The blood pressure level on treatment prior to withdrawal may be a useful indicator for identifying patients who are likely to successfully withdraw from antihypertensive therapy.
Some, although not all studies, have indicated that approximately 15–30% of patients may remain normotensive for extended periods following drug therapy withdrawal. [34, 35] Earlier studies involving nutritional interventions such as weight reduction, salt restriction and alcohol restriction suggest that the proportion remaining normotensive is enhanced with the addition of successful lifestyle interventions. For example, Blaufox et al. [36] studied nutritional interventions in a randomised, controlled trial of drug therapy withdrawal after 5 years of therapy. Weight loss of 4.6 0.5 kg or sodium restriction to 40 mEq per day increased the likelihood of remaining off drugs for 14 months; adjusted odds ratios of 3.43 (p < 0.05) and 2.17 (p < 0.05), respectively in comparison to controls (who ceased therapy but had no nonpharmacological intervention). Sixty per cent of those on weight loss (n = 87), 55% of those on salt restriction (n = 169) and 40% of controls (n = 202) remained off therapy after the 14–month follow-up period. In the same year, Stamler and colleagues showed that 44% of subjects withdrawn from medication and undertaking nutrition counselling (focussed on weight reduction, alcohol and salt restriction) remained normotensive after 3 years in comparison to 15% who received no counselling. [37]
Subjects in the withdrawal arm of the present study made relatively minor lifestyle changes, as determined by questionnaire. However, consistencies were observed in the maintenance of attempts to alter diet and exercise habits and the subsequent reduction in body mass index and body weight, which was sustained over the study period. In comparison, the continued treatment group appeared to make similar efforts in the initial 3 months but these efforts were not sustained over the duration of the study period, suggesting that withdrawal from medication may be a positive motivating factor for patients attempting to adhere to lifestyle behaviour changes.
Other factors need to be considered in interpreting these results. Firstly, it is difficult to attribute the successful drug withdrawal in this study solely to the reported lifestyle changes, which on objective grounds were minor. Pre-treatment blood pressure levels were not available in 34% of subjects and it is possible that these patients were not truly “hypertensive subjects” and may not have required blood pressure medication in the first instance. It is likely that a proportion of these subjects, even those with documented pre-treatment blood pressure levels indicating pharmacological therapy, may have “white-coat hypertension”. It is estimated through population studies that the prevalence of white-coat hypertension may be as high as 20–25%. [38, 39] It is also possible that major aggravating factors influencing blood pressure, e.g. excess body weight, alcohol intake and work stresses, may also have altered since the initiation of therapy. No data is available on these factors; hence their influence can not be determined. It is likely that the sustained normotension observed in these subjects is a combination of these factors acting together, rather than any specific factor such as the benefits of lifestyle change in isolation.
The sample size of this pilot study was based around detecting a 10–mmHg difference in systolic blood pressure between the two groups. A larger sample size would have enabled the detection of a smaller blood pressure difference between groups but the 10–mmHg difference was based on the clinical implication of a blood pressure change as a result of the cessation of drug therapy. Smaller differences, whilst statistically relevant, were considered unlikely to alter the patient’s management course in the context of general practice. It must also be stressed that the study sample is highly selected and therefore the results are relevant only to hypertensive patients who are considered by their GP to be suitable and are willing to participate in a lifestyle change intervention. Again it is important from a general practice health promotion perspective that the context in which a behaviour change intervention or blood pressure management change is presented to the patient is appropriate in the context of the reason for consultation. [40] This clearly leads to selection bias however is appropriate for the assessment of the strategy in the management of hypertensive patients in general practice.
An alternative design to the one adopted for the present study would be to include a group of patients who had medication withdrawn and who were provided with no lifestyle advice. Whilst this would have aided in the interpretation of the effect of lifestyle advice in the W group, it was considered inconsistent with appropriate patient management of hypertensive subjects in general practice.
For patients who had therapy re-instigated, the withdrawal of the drug programme provided the opportunity to re-evaluate the necessity of antihypertensive therapy. This procedure has confirmed that drug treatment is required in these subjects in order to maintain blood pressure at levels associated with a lower rate of cardiovascular events. The programme acted as a reinforcement for the benefit of drug treatment in these subjects.
Quality of life and general health measures were unchanged after participation in the lifestyle intervention programme. As subjects indicated small alterations in lifestyle behaviours, it is consistent that no significant alterations in quality of life were observed. It is also likely that the time period over which the study was conducted may not have been sufficient for lifestyle behaviour changes to significantly impact on quality of life. It is also likely that subjects who are physically capable of contemplating a lifestyle behaviour modification programme involving exercise may have a general health level which may not be significantly influenced by this type of activity.
The short-term duration of the study may also be considered as a limitation of the study and longer-term observation periods are required to determine whether the strategy has a role in long-term blood pressure control.
If maintained normotension with lifestyle interventions is possible in some patients, the issue of how to implement this type of management plan in general practice becomes critical. In recent years, there has been an increasing awareness of the role GPs may take in assisting patients to adopt lifestyle change for disease prevention. [40, 41] Focus group results suggested that the GPs were concerned with the implications, particularly related to safety, of drug withdrawal in treated hypertensive subjects. No adverse cardiovascular events were observed in the present study and a number of recent reports of drug withdrawal in the general practice setting have also demonstrated no excess risk of cardiovascular morbidity and mortality in patients withdrawn from therapy. [42] A 5–year follow-up of elderly patients withdrawn from therapy also suggests no adverse effects on morbidity and mortality in the long term. [43]
In conclusion, this study suggests that a lifestyle behaviour change programme based around self-help materials and advice from the general practitioner can assist a proportion of motivated patients to cease medication and remain normotensive for up to 9 months. Cessation of drug therapy may be an important motivating factor to achieve weight loss in this group. Outcome studies on the long-term impact of drug withdrawal are warranted to determine whether this approach has a role in the management of hypertension in general practice.
ACKNOWLEDGMENTS
The authors express their appreciation to the volunteer patients and general practitioners who have participated in the HEART Project. The National Heart Foundation of Australia (Vic Div) provided the use of facilities to conduct focus groups and interviews. This work has been conducted as part of the Better Health Program and been funded by a research grant from the Victorian Health Promotion Foundation.
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