What is the optimal cut-off threshold in self-home blood pressure measurement?: A cohort study according to STROBE statement

Abstract

Two aspects arise concerning the use of self-measured blood pressure monitoring to diagnose white-coat hypertension (WCH): the presence of target organ damage (TOD) and the normal cut-off threshold. This study aims to evaluate the cardiovascular risk of WCH according to different self-measured blood pressure normal cut-off thresholds and the influence of TOD at baseline. In all, 678 patients were followed for 6.2 years; 223 normotensive patients, 271 patients with sustained hypertension (HT), and 184 with WCH. TOD was defined as: left ventricular hypertrophy according to ECG, albuminuria, or low estimated glomerular filtration rate. The risk for different cutting points of self-measured blood pressure (<135/85mm Hg, <130/85mm Hg, and <130/80mm Hg) has been determined. The patients with HT experienced an increase in cardiovascular risk and death higher than the normotensive patients (odds ratio [OR] 7.9, 95% confidence interval [CI] 3.8–16.2 for sustained HT; and OR 3.5, 95% CI 1.6–7.4 for WCH). This was observed for all the cut-off thresholds analyzed. In white-coat hypertensive patients (cut-off <135/85mm Hg) with TOD, the risk was higher than in normotensive patients (OR 4.5; 95% CI 1.9–10.6). Using a self-monitoring blood pressure cut-off threshold of <130/80mm Hg without TOD at baseline, the WCH cases exhibited no differences in risk to the normotensive patients (OR 2.0, 95% CI 0.5–7.7). The decisions being taken for patients with WCH based on the presence of TOD and a self-administered home monitoring blood pressure measurement cut-off point probably lower than the one that is currently recommended. Abbreviations: ACEI = angiotensin-converting enzyme inhibitor, ARB = angiotensin receptor blocker, BMI = body mass index, BP = blood pressure, CV = cardiovascular, ESH = European Society of Hypertension, GFR = glomerular filtration rate, HT = hypertension, LVH = left ventricular hypertrophy, NT = normotension, SHT = sustained hypertension, SMBP = self-monitoring blood pressure, TOD = target organ damage, UAER = urinary albumin excretion rate, WCH = white-coat hypertension