Association of nocturnal hypertension with daytime blood pressure threshold and patient characteristics assessed by home blood pressure monitoring

Objectives Nocturnal hypertension, especially with well-controlled daytime blood pressure (BP), has emerged as a significant risk factor for cardiovascular disease. This study investigated its prevalence by morning home BP cut-off values and examined associated patient characteristics using data from the Japan Morning Surge-Home Blood Pressure (J-HOP) study. Methods This post hoc analysis included 2675 participants from the J-HOP study who had complete data on nighttime home BP, measured using validated automatic oscillometric devices. Nocturnal hypertension was defined as a nighttime systolic BP greater than or equal to 120 mmHg and diastolic BP greater than or equal to 70 mmHg. Results Among the participants, 60.5% had nocturnal hypertension. The proportion of patients with nocturnal hypertension decreased as the cut-off value for morning home BP was lowered: 40.5, 32.1, 23.7, and 14.6% for less than 135/85 mmHg, less than 130/80 mmHg, less than 125/75 mmHg, and less than 120/70 mmHg, respectively. The prevalence of nocturnal hypertension was significantly higher in individuals with diabetes compared with those without, at morning home BP thresholds of less than 135/85 mmHg (48.1 vs. 39.3%; P = 0.03) and less than 130/80 mmHg (41.0 vs. 30.6%; P = 0.01). Individuals taking diuretics had a significantly lower prevalence of nocturnal hypertension compared with those not taking diuretics, at a morning home BP threshold of less than 135/85 mmHg (35.3 vs. 42.9%; P = 0.01). Conclusion A considerable number of patients continued to show nocturnal hypertension even at lower morning home BP thresholds. Diabetes may contribute to nocturnal hypertension despite well-controlled morning BP, while diuretic use may help prevent it.