A case-comparison study of hypertension and hyperparathyroidism.

The frequency of hypertension in patients with primary hyperparathyroidism has been compared with that found in cases matched for conditions of comparable surgical magnitude, age, race, sex, and days in the hospital. The mean blood pressure of the patients was 143/89 mm Hg, significantly higher than that of controls, which was 130/81 mm Hg (P less than 0.001 for systolic and diastolic pressures). The difference was especially notable in view of the fact that the mean weight of the controls was 169 lb compared to 153.9 lb for the patients. Actual hypertension, defined as a diastolic blood pressure of 90 mm Hg or more and or treatment with hypertensive therapy was much more frequent in the patients (90 of 124; 73%) than in the controls (53 of 124; 43%; P less than 0.001). Serum creatinine was 1.3 mm/dl in patients and 1.1 mm/dl in controls. The blood pressure difference between patients and controls persisted when patients with creatinine levels of 2.0 mm/dl or less were omitted. The blood pressure difference between patients and controls had disappeared by the end of hospitalization. We conclude that primary hyperparathyroidism is associated with modest blood pressure elevation, that renal damage is probably not the mechanism, and that surgical cure perhaps may lower blood pressure. The mean effect of primary hyperparathyroidism is to shift the blood pressure distribution curve to the right by approximately 15/10 mm Hg.