Risk assessment and treatment benefit in intensively treated hypertensive patients of the hypertension optimal treatment (HOT) study

Background: The Hypertension Optimal Treatment (HOT) Study provided information about cardiovascular events in 18 790 hypertensives, subjected to pronounced blood pressure lowering for a mean of 3.8 years. Methods and Results: The HOT Study data have been further analysed after risk stratification of the patients (1999 World Health Organization and International Society of Hypertension guidelines criteria): (i) no patients of the HOT Study were classified as low risk, 50% were classified as medium risk, 20.2% as high risk and 29.8% as very high risk; (ii) incidence of cardiovascular events in these patients with excellent blood pressure control [92% had diastolic blood pressure (DBP) ≤ 90 mmHg] remained proportional to pretreatment risk. The relative risk of very high- versus medium-risk strata was between two and three both when HOT Study patients were considered independently of, or within the DBP target group they had been randomized to; and (iii) event rates in all risk strata were calculated to be much lower (possibly 60% lower) than rates expected from baseline risk calculated approximately by the Framingham equation. Conclusions: The low event rate in HOT Study patients is likely to result from pronounced blood pressure lowering, and is not explained by a lower risk profile than in previous controlled trials of antihypertensive treatment. The persistence of a risk gradient despite intensive blood pressure lowering suggests a combination of blood pressure control with other strategies of risk correction and the need to initiate antihypertensive therapy before complications develop.