JNC V created a significant paradigm shift in the evaluation and treatment of hypertension. As part of a major reclassification of hypertension, JNC V called "Stage I" what was previously termed mild hypertension (DBP: 90-104 mmHg). These patients were candidates for pharmacologic treatment after a reasonable trial of lifestyle modification. Hypertension was now defined as >140 mmHg SBP and/or >90 DBP. More than 50 million Americans were hypertensive using this new definition. Most experts agreed that a BP of <120/80 mmHg reflected the lowest risk group, with 120-140/ 80-90 mmHg an intermediate risk population. But there was no proof of the treatment benefit in those with intermediate risk, and no specific recommendations were made (19). JNC V highlighted the downward trend in stroke, CHD, and all-cause mortality from 1972 to 1990 per findings of the National Center for Health Statistics; a development strongly linked to heightened awareness and treatment of hypertension.
Emerging trial data allowed JNC V to recommend treatment in two important groups, those with ISH and aged persons with elevated DBP. In both, treatment superiority had previously not been proven before JNC V and some experts doubted the safety of phar-macotherapy. The Systolic Hypertension in the Elderly (SHEP) main trial in 1991 provided JNC V with an evidence-based management rationale. SHEP, with entry criteria of SBP >160 mmHg and DBP <90 mmHg, achieved a 32% risk reduction for all CV morbidity and mortality with active treatment (thiazide-like diuretic with a ^-blocker if needed) vs placebo. SHEP goals mandated SBP reduction by 20 mmHg, if 160-179 mmHg at entry; or below 160 mmHg, if >180 mmHg at entry (20). JNC V adopted these goals. Although treating Stage 2 and above ISH (SBP >160 mmHg) was now firmly evidence-based, no data existed then or even now regarding Stage 1 ISH (SBP = 140-159 mmHg and DBP <90 mmHg).
Studies examining therapy for aged persons with increased DBP (who typically have high SBP as well) were incorporated into JNC V. The Medical Research Council (MRC) trial in the elderly and the first Swedish Trial on Old Patients with Hypertension
(STOP-Hypertension-1) both documented unequivocal risk reduction with treatment for aged persons and validated earlier recommendations to treat these hypertensives (21,22).
By the time of JNC V, clinical trial data were still lacking regarding the value of intensive therapy in diabetics. Yet diabetes was understood to confer significantly increased CV risk, and JNC V advised that higher risk patients (such as diabetics) be treated to the goal of <130/85 mmHg. This was the first time that diabetics were assigned a lower therapeutic target (19).
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