Annual SBP variability tied to CVD death risk

High visit-to-visit variability (VVV) in systolic blood pressure (SBP) seems to increase the risk of cardiovascular disease (CVD) mortality, a recent Japan study has found.

A total of 72,617 participants (mean age 43.2±10.7 years, 86.6 percent men) were enrolled from the Japan Epidemiology Collaboration on Occupational Health Study. VVV was calculated using the coefficients of variation of SBP readings from 2008 to 2011. Fatal and nonfatal CVD outcomes were determined from their respective registries over a 7-year follow-up period.

Researchers reported 314 CVD events and 63 CVD deaths. The corresponding incidence rates were 7.64 and 1.53 per 10,000 person-years. Cox hazards regression analysis found that every 1-standard deviation increase in VVV led to a 42-percent increase in the risk of CVD mortality (hazard ratio [HR], 1.42, 95 percent confidence interval [CI], 1.32–1.54).

When taken as a categorical variable, patients in the highest vs lowest tertile of VVV were more than three times as likely to die of CVD causes (HR, 3.20, 95 percent CI, 1.26–8.17).

The relationship between VVV and total CVD events was less pronounced. As a continuous variable, each 1-standard deviation increase in VVV led to a slight but significant increase in CVD event risk (HR, 1.08, 95 percent CI, 1.02–1.15). However, as a categorical variable, VVV seemed to have no impact on CVD event risk (third vs first tertile: HR, 1.20, 95 percent CI, 0.90–1.60).

“This study showed that among the Japanese working population, increased VVV of SBP measured annually was associated with a significantly higher risk for CVD mortality while we did not find strong evidence with regard to CVD events,” the researchers said.