Study designs of evaluations included in the review
Only randomised controlled trials (RCTs) or quasi-RCTs of at least 8 weeks duration were eligible. Crossover RCTs were included provided they were of no more than two treatment arms and two periods. None of the trials had a reported duration of more than one year.
Specific interventions included in the review
Studies that directly compared a lifestyle intervention with a drug intervention were eligible for inclusion. Studies where the lifestyle intervention group also received varying antihypertensive medication were excluded. The included studies were of a low calorie diet versus a diuretic; low calorie, low sodium, high potassium diet versus a beta-blocker; a multiple intervention (weight reduction, low calorie, low sodium, exercise, and relaxation) versus a beta-blocker; biofeedback and relaxation response versus a betablocker, a diuretic or a centrally acting antihypertensive; weight reduction diet, low sodium and alcohol restriction diet versus a betablocker; and yoga versus an unspecified drug intervention.
Participants included in the review
Studies of adults with raised blood-pressure (BP at least 140/85 mmHg) were eligible for inclusion. Studies in which more than 50% of the patients had diabetes were excluded, as were studies of pregnant women. The included studies were of adults (mean age: 42 to 68 years, including one trial of elderly patients (age 60 to 80 years). Where reported, 75 to 100% of patients in the included studies were male.
Outcomes assessed in the review
The primary outcome measure used was clinical BP (systolic and diastolic). Cholesterol levels were also reported in some trials. Only studies from which intention-to-treat outcomes data were available were included. None of the available trials reported long-term cardiovascular outcomes.
How were decisions on the relevance of primary studies made?
One reviewer selected studies for inclusion and a second reviewer checked the decisions. Any disagreements were resolved by discussion.