White-Coat Hypertension Should Not Be Treated in Subjects With Diabetes

Blood pressure (BP) levels in the doctor's clinic may not always reflect those of daily living, as indicated by 24-h ambulatory or self-monitoring measurements. Simple logic implies that treatment should be guided by the actual BP levels, rather than by imprecise clinic measurements. On average, BP measured in the clinic is higher than out-of-office BP. This difference occurs in a considerable number of patients with white-coat hypertension (WCH). The issue is complicated, since most studies define WCH as an elevated office BP in patients with normal awake ambulatory BP. However, the “awake” state may not fully reflect the 24-h BP load. Average 24-h BP, and particularly that during sleep, which is more likely to be higher in subjects with diabetes (1,2), could be elevated in a patient with normal awake BP. The presence of abnormal clinic BP in such a patient discloses true hypertension rather than WCH. Indeed, among 4,121 subjects referred for ambulatory BP monitoring, 4.5% had isolated abnormal sleep BP (>120/70 mmHg) and normal 24-h BP (3). Nevertheless, in this presentation, we assume that the common definition of WCH is elevated clinic readings with normal awake BP.

Assessment of WCH in diabetes is complicated by the fact that normal BP measured at the clinic is defined as <130/80 mmHg (as opposed to 140/90 mmHg in the general population), whereas there are still no accepted thresholds for ambulatory or home-based BP levels.

Characteristics unique to the white-coat response in patients with diabetes, associated prognostic implications, and the need for treatment are discussed.