Diagnostic performance of simplified ambulatory nocturnal blood pressure monitoring for nocturnal hypertension and target organ damage assessment

OBJECTIVE: Nocturnal blood pressure (BP) is a more sensitive predictor of cardiovascular risk. However, frequent nighttime measurements may disrupt sleep and reduce patient compliance. Therefore, this study aimed to investigate whether simplified nocturnal or awake BP readings could effectively diagnose nocturnal hypertension (NHT) and assess associated target organ damage (TOD). METHODS: Two thousand four hundred seventy-five hypertensive patients with complete 24-h ambulatory BP monitoring (ABPM) data between January 2021 and December 2023 were recruited in this retrospective study. Six SBP indicators, including fixed-interval SBP, extended-interval SBP, evening SBP, morning SBP, daytime SBP, and morning-evening average SBP, were adopted to explore the agreement with mean nocturnal SBP and diagnostic potential for NHT, as well as their relationship with TOD. RESULTS: Among different SBPs, fixed-interval SBP (measured at 02 : 00, 03 : 00, and 04 : 00) showed the strongest correlation with nocturnal SBP (r = 0.961, P < 0.001). Bland-Altman analysis indicated good agreement, with a mean bias of 0.81 mmHg (95% confidence interval: 0.61-1.01) and 95.1% of data points falling within the limits of agreement, further supported by an intraclass correlation coefficient of 0.960. Compared to other five SBPs, fixed-interval SBP demonstrated the best diagnostic performance for NHT (area under the curve = 0.974, P < 0.001) with the optimal cut-off 120.5 mmHg. Logistic analysis confirmed that fixed-interval SBP remained independently associated with TOD risk after multivariable adjustment. CONCLUSION: Our analysis suggests that a simplified 3-time-point nocturnal SBP protocol might be considered as a potential alternative to conventional ABPM for diagnosing NHT and evaluating TOD.