P807Short-term versus visit-to-visit blood pressure variability as predictor of early adverse cardiovascular outcome in hypertension

Abstract

Abstract Background Blood pressure variability (BPV) has emerged as an important predictor of future cardiovascular events among hypertensive patients. However, it is not known whether BPV measured with ambulatory monitoring (short-term BPV) or computed from office visits (visit-to-visit BPV) are related to each other and carry similar prognostic significance. Purpose To investigate the association of short-term BPV and visit-to-visit BPVs with cardiovascular and renal events in a young hypertensive cohort untreated at baseline. Methods Short-term BPV was measured from 24-hour blood pressure (BP) monitoring at baseline in 1167 participants with stage 1 hypertension from the HARVEST study, aged 33.1±8.5 years. Visit-to-visit BPV was calculated from office BP measured in triplicate at each visit. Visits were made two weeks apart at baseline, and then after 1 month, 2 months, 3 months, 6 months, and 1 year. Only untreated subjects were taken into account for the analysis. Hazard ratios for short-term (weighted 24-hour BP Standard Deviation) and visit-to-visit Standard Deviation were computed, adjusting for the corresponding average BP, age, sex, body mass index, 24h heart rate, smoking, alcohol and coffee consumption, physical activity, parental cardiovascular disease, glucose, total cholesterol, HDL-cholesterol, and nocturnal BP dipping. Results Short-term systolic BPV showed a weak correlation with visit-to-visit BPV (p=0.018). No correlation was found for diastolic BPVs. Independent predictors of short-term BPV were average 24h BP, smoking, and nocturnal dipping. Predictors of visit-to-visit BPV were average office BP, parental cardiovascular disease, female gender, and nocturnal dipping. During a 15.4-year follow-up, 95 end-points were observed. In a parsimonious multivariable Cox model, short-term systolic BPV (p=0.03) was an independent predictor of the endpoints with a 7% increase in risk for each 1 mmHg increment in systolic BPV. The hazard ratio for a short-term systolic BPV ≥12.8 mmHg was 2.03 (95% CI, 1.34–3.05, p=0.0007). This threshold value was identified by ROC curve analysis. The association was particularly strong for coronary events (N=41) with a hazard ratio of 3.45 (95% CI, 1.73–6.89, p=0.0004). No independent association with outcome was found for visit-to-visit systolic or diastolic BPV (p>0.66). Similar results were obtained when average real variability was used instead of standard deviation as a metric of visit-to-visit BPV (p>0.15). Conclusions These data show that in untreated young hypertensive people short-term BPV and visit-to-visit BPV have a weak relationship and a different clinical significance. Only short-term BPV measured with ambulatory monitoring improved traditional risk prediction models in this setting. Acknowledgement/Funding Associazione 18 maggio 1370