Prognosis in therapy-resistant hypertension.

OBJECTIVES: To study the prognosis in therapy-resistant hypertension (RH).
DESIGN: Patients with RH and age- and sex-matched responding hypertensives, were followed-up for a period of 7 years.
SETTING: All subjects were outpatients at a secondary referral centre for hypertension.
SUBJECTS: (i) Age < or = 65 years; (ii) no prior diagnosis of secondary hypertension; (iii) on antihypertensive triple-drug therapy of optimal dosage; (iv) diastolic blood pressure remaining 5 mmHg above their (age-related) target pressure; (v) no history of renal failure, heart failure, stroke or myocardial infarction; and (vi) no record of noncompliance. A total of 800 patients were screened. Thirty-six were finally included. For each study patient, two control patients were randomly selected.
INTERVENTIONS: Continuous efforts to optimize blood pressure control were made in all patients. MAIN OUTCOME MEASURES: Transient ischaemic attack or stroke, myocardial infarction, congestive heart failure, renal failure, and death. Development of non-insulin-dependent diabetes mellitus (NIDDM).
RESULTS: At the end of the follow-up period, RH had a casual functional blood pressure 2/6 mmHg higher than the control hypertensives. RH exhibited an increased incidence of stroke (P < 0.05), renal insufficiency (P < 0.05) and NIDDM (P < 0.05). RH patients had an increased risk of suffering an event during the 7 years [odds ratio (OR) 2.71; P < 0.05].
CONCLUSIONS: Resistance to antihypertensive therapy may persist even when therapy is aggressively applied in compliant patients. RH is associated to an increased risk of stroke and of target organ damage, foremost renal insufficiency. The apparent association between RH, obesity and NIDDM may imply that hyperinsulinaemia is involved in therapy resistance.