Dipping pattern and short-term blood pressure variability are stronger predictors of cardiovascular events than average 24-h blood pressure in young hypertensive subjects

Aims: The role of increased blood pressure (BP) variability and a blunted day-night BP drop is still being debated, particularly in young hypertensive subjects. We investigated the contribution of BP variability and day-night BP changes combined to cardiovascular events in initially untreated young hypertensive individuals. Methods and results: We selected 1794 subjects aged ≤45 years from the HARVEST and the PIUMA studies, two long-term observational studies in subjects with hypertension. The outcome was a composite pool of non-fatal myocardial infarction or stroke, heart failure needing hospitalization, death from cardiovascular causes, and myocardial or limb revascularization procedures. During an 11.3-year follow-up, 140 cardiovascular events were accrued. A multivariable Cox model which included BP variability and non-dipping was more informative (Akaike Information Criterion = 1536.9) than the model which included average of 24-h BP (Akaike Information Criterion = 1553.6). A higher hazard ratio (HR) was observed for non-dipping [HR 2.22; 95% confidence interval (CI): 1.55-3.17; P < 0.0001] and for high BP variability (HR 1.84; 95% CI: 1.26-2.65; P = 0.0015) than for high average 24-h BP (HR 1.58; 95% CI: 1.07-2.33; P = 0.020). When average 24-h ambulatory BP was included in a nested model, the -2log likelihood decreased from 1524.9 to 1519.3, and there was a tendency for an interactive effect between 24-h BP and non-dipping on risk of cardiovascular events (P = 0.092). Conclusion: In young hypertensive individuals, prognostic models including BP variability and non-dipping pattern provide better information than models with average 24-h ambulatory BP alone. More consideration should be given to BP variability and the day-night BP pattern beyond the average 24-h ambulatory BP in young hypertensive subjects.