Hypertension Detection and Follow-up Program (HDFP)

Background:

The NIH-supported HDFP program sought to screen defined populations in communities to detect those with hypertension, to invite them to participate in a trial of stepped care, an idealized care of hypertension, and to evaluate cause-specific and total mortality based on such a program. It was not a placebo drug trial, nor a trial of one specific therapy against another, but an idealized detection, treatment and follow-up program compared to referred care through usual community sources. The endpoint was whether such an idealized program would reduce total mortality. The secondary goals were to determine whether a substantial proportion of hypertensives could be detected, brought under management, and brought to control levels of blood pressure and whether this treatment was more beneficial than toxic, whether it was as effective in young as well as old, in women as well as men and in blacks as well as whites.

Method:

Estimated sample size would demonstrate a significant difference at the 95% level with a power of 0.9 within a 5-year period. That design resulted in screening of 160,000 people and detection of about 10,900 with a mean diastolic pressure of 90 millimeters or more on two random zero readings, after exclusions for some medical and social conditions. Therapy in multiple U.S. centers with special care was performed in a standardized stepwise sequence with step one being a diuretic, step two an anti-adrenergic drug such as reserpine, and step three a vasodilator such as hydralazine, a diuretic such as chlorthalidone. A well-established system of governance and central data handling and data evaluation was followed in this national effort.

Results:

More than two-thirds of the stepped care subjects continued on medications and more than half of them achieved blood pressure levels in the range below 90 millimeters diastolic. Blood pressure control was consistently better in the stepped care group than in the referred care group and five-year mortality from all causes was 17% lower overall and 20% lower for those with moderate to high hypertension (95r to 104 diastolic).

Conclusions:

A systematic approach to the screening, detection, treatment, control, and follow-up of hypertensives in the general population was effective in reducing mortality, including in so-called mild hypertensives. Analysis revealed that the decreased total mortality was not due to differences in overall risk factor changes between the two groups, and could therefore be attributed to the better control of blood pressure. Because this group makes up about three-quarters of hypertensives in the population and because this was a community-based effort, it was concluded that such a strategy can be successful in achieving and maintaining systematic long-term control of elevated blood pressure.

The design of the trial could not exclude biased ascertainment of the specific causes of death but with this caveat, cerebrovascular deaths were reduced almost 45% and myocardial infarction by 26% with 14% fewer CVD deaths. (HB)