A large body of clinical trial data indicates that a given difference in blood pressure (BP), as measured in the clinic, results in a given difference in outcome. This correlation underpins current US and European guidelines for the management of hypertension. However, findings fromrecent comparative trials may appear inconsistent with a fixed relationship between BP lowering and outcome benefit, at least at all BP ranges, at all levels of total cardiovascular risk and with all drug combinations. We review the findings of six of these recent trials and conclude that their complex design precludes a simple interpretation, that several important questions remain unanswered and that direct evidence - particularly in support of lowering systolic BP below 140 or 130mmHg - is urgently needed. © 2009 Wolters Kluwer Health.