Hypertension Detection and Follow-up Program (HDFP)
Condition: Cardiovascular Diseases; Heart Diseases; Hypertension; Vascular Diseases
MeSH terms: Hypertension; Cardiovascular Diseases; Heart Diseases; Vascular Diseases
Study type: Interventional
Phase: Phase 3

Summary: 
      To determine the effectiveness of systematic, sustained, antihypertensive therapy in reducing
      morbidity and mortality from hypertension in a wide spectrum of persons with elevated blood
      pressure in 14 communities. During its course, the trial also obtained a direct measure of
      the prevalence, severity, and treatment status of representative white and black populations
      with high blood pressure in these 14 communities, and obtained an estimate of the extent of
      attainable reduction of complications of high blood pressure by an organized screening and
      blood pressure management program.
    

Detailed description: 
      BACKGROUND:

      Published data from the Veterans Administration Cooperative Study of Hypertension
      demonstrated that reduction in morbidity and mortality could be attained by treating men with
      fixed diastolic blood pressure over 105 mm Hg. Similar trends occurred for those with fixed
      diastolic blood pressure between 90 and 104 mm Hg. Results and current trends from other
      studies supported these findings. However, prior to inception of the Hypertension Detection
      and Follow-up Program (HDFP), it was not known whether benefits from antihypertensive therapy
      applied to all hypertensives in the general population and whether making use of existing
      medical knowledge could significantly reduce morbidity and mortality from hypertension in
      communities.

      Recognizing this need, NHLBI initiated the pilot activities of the HDFP to characterize
      significant operational, socioeconomic, and motivational factors that would influence the
      acceptance of antihypertensive therapy in the defined populations within which the controlled
      clinical trial would take place and to obtain baseline information necessary to the
      undertaking of the clinical trial, which was to determine whether a practical, intensive, and
      antihypertensive program could significantly reduce morbidity and mortality in hypertensives
      in the general population.

      The planning of the trial, including the development of a protocol and manual of operations,
      began in 1971. Between February 1973 and May 1974, 158,906 persons were screened for high
      blood pressure in 14 communities. A total of 10,940 hypertensive participants were
      randomized.

      The primary hypothesis tested by the trial was that intensive blood pressure control under
      stepped care for five years could significantly reduce mortality compared with that under
      referred-care. Stepped-care was the method of treatment in HDFP clinics in which a diuretic
      was given initially and additional antihypertensive agents were added in a time-structured,
      stepwise fashion until goal blood pressure was achieved. Referred-care represented referral
      to private physicians and other community sources of care. Participating in this study were
      14 clinical centers, a coordinating center, ECG center, central laboratory, and monitoring
      laboratory.

      The clinical phase of the trial ended in May 1982. The project was extended into 1983 in
      order to continue the surveillance of mortality and blood pressure control.

      DESIGN NARRATIVE:

      The trial was a randomized, non-blind, fixed sample trial with single intervention and
      control groups. The intervention group received stepped care from the clinical trial clinics
      (see Background, below), while those in the control group were referred to their own
      physicians. Each community contributed both stepped-care and referred-care participants, but
      for analysis purposes, the groups were pooled into two groups. The primary endpoint was
      mortality. The effects of stepped- vs. referred-care were also assessed on intermediate and
      secondary factors, including nosologic codes of specific causes of mortality, nonfatal
      myocardial infarction, stroke, hypertensive heart disease, and EKG abnormalities.
    

Intervention name(s): diuretics; antihypertensive agents
Intervention type(s): Drug; Drug
Intervention MeSH terms: Antihypertensive Agents; Diuretics
Allocation: Randomized
Primary purpose: Prevention