REPRODUCIBILITY OF NIGHT-TIME BLOOD PRESSURE PHENOTYPES. RESULTS FROM THE HARVEST

Objective: Night-time blood pressure (BP) assessed with ambulatory monitoring has a greater prognostic value than daytime BP but whether this is due to night-time hypertension being more reproducible than daytime hypertension is unclear. The aim of the study was to investigate the reproducibility of ambulatory BP subperiods and nocturnal dipping phenotypes assessed twice 3 months apart in young-to-middle-age untreated subjects screened for stage 1 hypertension. Design and method: We investigated 1096, 18-to-45-year old subjects from the HARVEST. Their office BP was 145.8±10.5/93.7±5.8 mmHg. Office BP and 24h BP were measured at baseline and after 3 months. Office, 24-h, daytime and night-time hypertensions, and nocturnal dipping patterns were defined according to the 2023 ESH guidelines. Definitions were based on systolic BP (SBP), diastolic BP (DBP) or either pressure. Agreement was evaluated with Kappa statistics. Results: Correlation coefficients between baseline and repeat measurements were 0.44 and 0.45 for office SBP and DBP, 0.68 and 0.66 for 24h, 0.65 and 0.65 for daytime, and 0.59 and 0.57 for nigh-time BPs, respectively. Reproducibility evaluated with weighted Kappa (K) was moderate for 24h hypertension (0.54 for SBP, 0.58 for DBP, 0.48 for either pressure), was lower but still moderate for daytime hypertension (0.42, 0.45, and 0.43, respectively), and was fair to moderate for night-time BP (0.41, 0.37, and 0.36, respectively). Between-measurement agreement was even worse for isolated night-time hypertension (K=0.20), and poor for office hypertension (K=0.14). Non-dipping was present in 31.8%, 31.2%, and 45.0% of participants, respectively, when based on SBP, DBP or either pressure, and showed a fair agreement (K=0.26, 0.23, and 0.30, respectively). Poorer agreement was shown by extreme dipping (K=0.18) and by reverse dipping (K=0.07). Conclusions: These data show that within the ambulatory sub-periods, 24h hypertension has the best and night-time hypertension the worst reproducibility. Thus, the better association with adverse outcomes shown by night-time hypertension compared to daytime hypertension in observational studies is not due to a better reproducibility of the former. The agreement was even worse for dipping phenotypes, especially for extreme and reverse dipping. Thus, dipping patterns should be confirmed with repeat ambulatory BP monitoring.