INTERPRETATION OF PROSPECTIVE TRIALS IN HYPERTENSION - DO TREATMENT GUIDELINES ACCURATELY REFLECT CURRENT EVIDENCE

Objective To review the findings of prospective controlled trials of a ntihypertensive treatment and determine whether the evidence they have provided is embodied satisfactorily in current national and internati onal guidelines for hypertension management Management guidelines Conv entional guidelines all advise prompt treatment of moderate-to-severe hypertension and treatment of even mild hypertension in subjects with cardiovascular disease, target organ damage or diabetes, and in the el derly; and treatment of isolated systolic hypertension in the elderly. All acknowledge that evidence for efficacy and safety of treatment is strongest for thiazide diuretics and beta-blockers. Uncomplicated mil d hypertension Conventional guidelines all emphasize the importance of long-term blood pressure, measured over some months, for treatment de cisions. However the blood pressure for routine treatment varies from 160/100 mmHg (British Hypertension Society) to 140/90 mmHg (Joint Nati onal Committee V). This dictates very large differences in the number of patients to be treated to prevent a cardiovascular disease event an d in the proportion of the population to be treated, yet the reasons f or these differences are not explicit None of the conventional guideli nes is entirely satisfactory. The more conservative British Hypertensi on Society policy may leave untreated some middle-aged men who ought t o be treated. The more aggressive Joint National Committee V policy wi ll lead to treatment of some young subjects who have only a remote cha nce of benefit, at very high cost, and possibly with adverse harm-bene fit consequences. Risk-based guidelines Guidelines developed in New Ze aland target absolute cardiovascular disease risk in mild hypertension and have the potential to correct this shortcoming of conventional gu idelines. However they require further consideration as regards the nu mber needed to treat which is acceptable to well-informed patients, th e appropriate estimate of relative cardiovascular disease risk reducti on by treatment in mild hypertension, the pattern of treatment which w ill emerge and their acceptability in ordinary practice. Conclusion Co mparative evaluation will be needed to determine whether the outcome i s better with conventional guidelines, which are simple but at the exp ense of accuracy, or with risk-targeted guidelines, which are more acc urate but at the expense of simplicity.