Association of night-time home blood pressure with night-time ambulatory blood pressure and target-organ damage: a systematic review and meta-analysis

Objective: Night-time ambulatory blood pressure (nABP) is the most important aspect of the blood pressure profile in terms of prognosis. Novel low-cost home monitors allow automated night-time blood pressure monitoring (nHBP). This study reviewed the evidence on the association of nHBP with nABP and preclinical organ damage. Methods: Systematic review and meta-analysis. Results: Analysis of six studies (n = 1404) showed pooled difference between nHBP and nABP (SBP/DBP) at 1.4, 95% confidence interval (CI) 0.3, 2.6/-0.2, 95% CI - 0.9, 0.6 mmHg, whereas the pooled correlation coefficient between nHBP and nABP (SBP/DBP) was r = 0.70, 95% CI 0.59, 0.81/r - 0.72, 95% CI 0.67, 0.77, respectively. Two studies (n = 212) investigated the agreement between nHBP and nABP in detecting nondippers with weighted agreement 77.3% (pooled kappa 0.27, 95% CI 0.08, 0.45). Three studies (n = 954) reported on the association of left ventricular mass index with systolic nHBP and nABP (pooled correlation coefficient r = 0.36, 95% CI 0.23, 0.50 and r = 0.32, 95% CI 0.10, 0.54, respectively, P = NS for comparison). Two studies (n = 950) reported on the association of urinary albumin excretion with systolic nHBP and nABP (pooled r = 0.39, 95% CI 0.21, 0.58 and r = 0.30, 95% CI 0.06, 0.55, respectively, P < 0.01 for comparison). Two studies (n = 350) reported on the association of common carotid intima-media thickness with systolic nHBP and nABP (pooled r = 0.31, 95% CI 0.16, 0.46 and r = 0.35, 95% CI 0.17, 0.53, respectively, P = NS for comparison). Conclusion: The available evidence suggests that nHBP and nABP present similar values and comparable relationship with target-organ damage. Studies on the prognostic value of nHBP are needed.