High blood pressure: when is medication needed for hypertension?
High blood pressure management is fundamental for the prevention and treatment of heart attacks, strokes and kidney disease. What should be the target blood pressure for medication? Overmedication is common and can damage function with adverse effects on quality of life. The authors of an intervention review published recently in the highly respected Cochrane Library examine all the relevant randomized controls trials and come to the conclusion that medicating mild hypertension (systolic blood pressure (BP) 140-159 mmHg and/or diastolic BP 90-99 mmHg) confers no benefit. They begin by stating:
"Individuals with mildly elevated blood pressures, but no previous cardiovascular events, make up the majority of those considered for and receiving antihypertensive therapy. The decision to treat this population has important consequences for both the patients (e.g. adverse drug effects, lifetime of drug therapy, cost of treatment, etc.) and any third party payer (e.g. high cost of drugs, physician services, laboratory tests, etc.)."
They examined evidence comparing the health outcomes between treated and untreated individuals with mildly high blood pressure in order to...
"...quantify the effects of antihypertensive drug therapy on mortality and morbidity in adults with mild hypertension (systolic blood pressure (BP) 140-159 mmHg and/or diastolic BP 90-99 mmHg) and without cardiovascular disease."
So they searched an extensive collection of databases for random controlled trials (RCTs) lasting at least a year. These included MEDLINE extending from 1948 to 2011, EMBASE from 1980 to 2011, and others. The also searched the Cochrane Database of Systematic Reviews and the Database of Abstracts of Reviews of Effectiveness (DARE) for reviews and meta-analyses of high blood pressure drug treatment compared to placebo or no treatment. They used death, stroke, coronary heart disease (CHD), total cardiovascular events (CVS), and withdrawals due to adverse effects as their primary outcomes. What did the data show?
"Treatment for 4 to 5 years with antihypertensive drugs as compared to placebo did not reduce total mortality. In 7,080 participants treatment with antihypertensive drugs as compared to placebo did not reduce coronary heart disease, stroke, or total cardiovascular events. Withdrawals due to adverse effects were increased by drug therapy, ARR 9%."
While it is well established that appropriate medication for moderate-severe hypertension reduces heart attacks, strokes and kidney disease, this study and other evidence suggests that medication confers no benefit for mild high blood pressure. Lifestyle and other interventions are likely preferable. The authors conclude:
"Antihypertensive drugs used in the treatment of adults (primary prevention) with mild hypertension (systolic BP 140-159 mmHg and/or diastolic BP 90-99 mmHg) have not been shown to reduce mortality or morbidity in RCTs. Available data from the limited number of available trials and participants showed no difference between treated and untreated individuals in heart attack, stroke, and death. Treatment caused 9% of patients to discontinue treatment due to adverse effects. More RCTs are needed in this prevalent population to know whether the benefits of treatment exceed the harms."
It is not at all unusual for patients to come to my practice having been unnecessarily medicated for blood pressure lower than 140-159 mmHg and/or diastolic BP 90-99 mmHg. In addition to the obvious cautions, clinicians must remember that as the circulatory system becomes less elastic with age it can require a little more pressure to perfuse the brain and the rest of the body with blood and oxygen. The full text of this important review is available here. For a thorough review of blood pressure guidelines, including special considerations for diabetes and kidney disease, see the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment ofHigh Blood Pressure.