Nocturnal hypertension or nondipping: which is better associated with the cardiovascular risk profile?

Both increased night blood pressure (BP) and nondipping are associated with worse cardiovascular risk and prognosis. However, as they are often related features, their relative importance has been difficult to assess separately. In this study we address separate associations of nocturnal hypertension and nondipping with cardiovascular risk profile in treated and untreated hypertensive patients.

A total of 37,096 untreated patients and 62,788 patients receiving antihypertensive treatment from the Spanish Ambulatory Blood Pressure Monitoring Registry were included. Each cohort was separated into 4 groups: group 1, night systolic blood pressure (SBP) <120 mm Hg and normal dipping (>10%); group 2, night SBP <120 mm Hg and nondipping (≤10%); group 3, nocturnal hypertension (SBP ≥120 mm Hg) and normal dipping; and group 4, nocturnal hypertension and nondipping.

The smallest proportion of patients with additional cardiovascular risk factors, organ damage, and history of previous events was observed in the group with both normal night SBP and dipping, whereas those with both nocturnal hypertension and nondipping showed the largest proportion of cardiovascular risk factors and diseases. When groups showing only 1 abnormality were compared, nondipping was associated with female sex, reduced renal function, and previous cardiovascular events, whereas nocturnal hypertension was associated with male sex, smoking, and increased urinary albumin excretion. In treated patients, it was also associated with the presence of diabetes.

Nondipping is related to more advanced disease (reduced renal function and clinical evidence of cardiovascular disease), whereas nocturnal hypertension is associated with albuminuria. The worst cardiovascular risk profile is present in patients exhibiting both nocturnal hypertension and nondipping.