Implications for practice
Choice of first-line treatment, morbidity and mortality evidence versus placebo or no treatment.

• Most of the available evidence justifying treatment of patients with elevated blood pressure used a thiazide as the first-line drug.
• First-line low-dose thiazides are more effective than first-line high-dose thiazides and first-line beta-blockers.
• Evidence for first-line ACE inhibitors is similar to low-dose thiazides but less robust and ACE inhibitors are more expensive than thiazides.
• Evidence for first-line calcium channel blockers is insufficient.
• There are no RCTs comparing first-line use of other classes of drugs such as angiotensin receptor blockers or alpha blockers.
• Morbidity and mortality benefit depends on the drug class received, not the BP achieved.

Blood pressure measurement.

• Blood pressure must be measured (average of multiple readings) using proper technique with patient non-stimulated and resting for at least five minutes.

Population.

• Moderate evidence for secondary prevention, survivors of TIA, stroke or myocardial infarction age 55 to 80 years, BP ≧ 140/90 mmHg.
• Good evidence for primary prevention adult patients with moderate to severe hypertension, BP ≧ 160/100 mmHg.
• Weak evidence for primary prevention adult patients with mild hypertension BP < 160/100 and ≧140/90 mmHg.
• BP targets are only achieved in about 60% of patients with mild, moderate and severe hypertension treated with stepped care antihypertensive drugs.

Implications for research
At the present time RCT data versus placebo or no treatment is lacking for all classes other than thiazides as first-line treatment. Since we have clear evidence of effectiveness of first-line low dose thiazides in primary prevention patients with blood pressure of ≧ 160/100 mmHg and secondary prevention patients with lower BPs, it would be unethical to do further trials for this population compared to a placebo or untreated control group. Future RCTs in these populations should be done with low-dose first-line thiazides as the comparison group. The benefits and harms of treatment of primary prevention patients with lower blood pressures remains uncertain at the present time. Large trials recruiting primary prevention patients in lower blood pressure categories and using first-line low-dose thiazides compared to placebo are needed.


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