Undiagnosed sleep-disordered breathing among male nondippers with essential hypertension

OBJECTIVE: A blunting of the nocturnal fall in arterial blood pressure is found in a minority of patients (nondippers) with essential hypertension. We tested whether sleep-disordered breathing (snoring and apnea or hypopnea) might explain such a finding for male patients, among whom its prevalence is much higher. SETTING AND PATIENTS: We studied 100 new cases of hypertension in men, observed consecutively by a local group of general practitioners and diagnosed essential hypertensives in a referral clinic. By using 24 h ambulatory blood pressure monitoring with a SpaceLabs 90207 device, 15 patients were classified initially nondippers (daytime ambulatory blood pressure > or = 136/87 mmHg; night-time decrease by 10 in 10 cases). Six of the control patients breathed normally and four snored nonapneically. There was a normal fall in nocturnal blood pressure in all 10 cases. CONCLUSIONS: The nondipper condition appears to be associated with undiagnosed apneic snoring for an unselected population of previously untreated male subjects with a diagnosis of essential hypertension. Ambulatory blood pressure monitoring of such patients is of limited diagnostic value.