Ambulatory Blood Pressure Thresholds for Diagnosis of Hypertension in Patients With and Without Type 2 Diabetes Based on Cardiovascular Outcomes

Currently recommended ambulatory blood pressure (BP) monitoring (ABPM) thresholds for diagnosis of hypertension do not differentiate, as international guidelines do for clinic BP, uncomplicated persons at low risk from those at higher risk, e. g., patients with diabetes, for target injury and cardiovascular disease (CVD) risk. We aimed to derive diagnostic thresholds for the awake and asleep systolic (SBP) and diastolic (DBP) BP means based upon CVD outcomes (death from all causes, myocardial infarction, angina pectoris, coronary revascularization, heart failure, acute arterial occlusion of the lower extremities, thrombotic occlusion of the retinal artery, hemorrhagic stroke, ischemic stroke, and transient ischemic attack) for patients with and without diabetes. We prospectively studied 3344 subjects (1718 men/1626 women), 52.6 +/- 14.5 (mean +/- SD) yrs of age, 607 with type 2 diabetes, during a median follow-up of 5.6 yrs. Those with hypertension at baseline were randomized to ingest all their prescribed hypertension medications upon awakening or the entire daily dose of >= 1 of them at bedtime. At baseline, BP was measured at 20-min intervals from 07:00 to 23:00 h and at 30-min intervals at night for 48 h, and physical activity was simultaneously monitored every minute by wrist actigraphy to accurately derive the awake and asleep BP means. Identical assessment was scheduled annually and more frequently (quarterly) if treatment adjustment was required. Cox regression analysis was used to derive outcome-based reference thresholds for ABPM in subjects with and without diabetes. CVD risk was consistently greater in patients with than without diabetes for awake SBP/DBP means >= 130/75 mm Hg and asleep means >= 110/65 mm Hg. Derived outcome-based reference thresholds for persons without diabetes were 135/85 mm Hg for the awake and 120/70 mm Hg for the asleep SBP/DBP means. In terms of CVD outcome, the equivalent cutoff threshold values for patients with diabetes were 120/75 mm Hg for the awake and 105/60 mm Hg for the asleep SBP/DBP means. Outcome-based reference thresholds for the diagnosis of hypertension were 15/10 mm Hg lower for ambulatory SBP/DBP in patients with than without diabetes. This marked difference indicates the need for revision of current guidelines that propose diagnostic thresholds for ambulatory BP without differentiation between the presence/absence of diabetes. (Author correspondence: rhermida@uvigo.es)