NEW METAANALYSIS OF TREATMENT TRIALS OF HYPERTENSION - IMPROVING THE ESTIMATE OF THERAPEUTIC BENEFIT

The objectives of this sub group meta-analysis on the treatment of hyp ertension was to: (1) highlight specific results of well-designed tria ls; (2) group trials according to their specific clinical context; (3) express results of the meta-analysis in absolute reduction terms; and (4) estimate the bias of withdrawal because of blood pressure increas e. This meta-analysis is based on summarised published results from ra ndomised controlled trials, comparing a drug treatment versus placebo or no treatment, with morbi-mortality as the principle outcome. The fo llowing data were analysed: (1) total mortality; (2) cardiovascular mo rtality; (3) stroke; (4) major coronary events; and (5) congestive hea rt failure. The treatment significantly reduced the incidence of all o utcomes in trials involving older patients, avoiding up to nine stroke s (OR = 0.66, 95% CI: 0.56-0.77) and four major coronary events (OR = 0.79, 95% CI: 0.58-0.92) every 1000 patient-years when the bias of wit hdrawal was taken into account. The only outcome significantly influen ced by treatment in younger patients with mild-to-moderate hypertensio n was stroke, with one stroke avoided every 1000 patient-years (OR = 0 .51, 95% CI: 0.39-0.66). There was insufficient statistical power in t he trials which enrolled patients with non-moderate hypertension to re ach clinical significance, except for the reduction in the incidence o f congestive heart failure. However, the results indicated a trend tow ards greater absolute benefit under treatment. Trials enrolling patien ts with post-stroke hypertension also had insufficient power, but sugg ested benefit by the reduction of the incidence of stroke recurrence a nd congestive heart failure under treatment. In conclusion, the most c onstant treatment benefit concerned stroke, although the absolute redu ction was very modest in younger patients with mild-to-moderate hypert ension. Only the results from trials in older patients showed a signif icant reduction of major coronary events. Such results need further an alyses, ideally based on individual patient data.