3.1 OUTCOME-DRIVEN THRESHOLDS FOR AMBULATORY PULSE PRESSURE IN 9938 PEOPLE RECRUITED FROM 11 POPULATIONS

Abstract

Background. Evidence-based thresholds for risk stratification based on pulse pressure (PP) are currently unavailable. Methods. To derive outcome-driven thresholds for the 24-h ambulatory PP, we analyzed 9938 people randomly recruited from 11 populations (47.3% women). After age stratification (<60 vs. ≥60 years) and using average risk as reference, we computed multivariable-adjusted hazard ratios (HRs) to assess risk by tenths of the PP distribution or risk associated with stepwise increasing (+ 1 mm Hg) PP levels. Results. Among 6028 younger participants (68,853 person-years), the risk of cardiovascular (HR, 1.58; P = 0.011) or cardiac (HR, 1.52; P = 0.056) events increased only in the top PP tenth (mean, 60.6 mm Hg). Using stepwise increasing PP levels, the lower boundary of the 95% confidence interval of the successive thresholds did not cross unity. Among 3910 older participants (39,923 person-years), risk increased (p≤0.028) in the top PP tenth (mean, 76.1 mm Hg). HRs were 1.30 and 1.62 for total and cardiovascular mortality, and 1.52, 1.69 for all cardiovascular, cardiac events. The lower boundary of the 95% confidence interval of the HRs associated with stepwise increasing PP levels crossed unity at 64 mm Hg. While accounting for all covariables, the top tenth of PP contributed less than 0.3% (generalized R2 statistic) to the overall risk among elderly. Conclusions. In randomly recruited people, ambulatory PP does not add to risk stratification below age 60; in the elderly, PP is a weak risk factor with levels below 64 mm Hg probably being innocuous.