Ambulatory better than central BP at predicting death, cardiovascular events in dialysis patients

Central blood pressure (BP) is associated with all-cause mortality and cardiovascular events in haemodialysis patients, reveals a study. However, its prognostic value is not superior to ambulatory peripheral BP.

In this multicentre prospective study, a team of investigators measured central BP noninvasively on a midweek nondialysis day and collected interdialytic ambulatory BP and predialysis BP. A composite of major adverse cardiovascular events (MACE) and all-cause mortality were the primary outcomes.

The investigators also assessed the agreement between central and ambulatory BP using Cohen’s Kappa index and Bland–Altman plot. Finally, they determined the association of BP parameters with outcomes using linear and nonlinear Cox regression models.

A total of 368 patients were included, of whom 366 had their central BP measured. Central BP showed a moderate agreement with ambulatory BP in defining hypertension (κ, 0.42) with wide limits of agreement in Bland–Altman analysis.

Central pulse pressure, ambulatory systolic BP, and ambulatory pulse pressure correlated with all-cause mortality after a median follow-up of 51.5 months. On the other hand, all BP parameters, except for predialysis diastolic BP, significantly predicted MACE.

However, only ambulatory pulse pressure was found to be predictive of both all-cause mortality and MACE when evaluated in a stepwise variable selection Cox model. In nonlinear Cox models, no significant nonlinear trend was found concerning the association between central BP and outcomes.

“Our data support the superiority of ambulatory BP in the dialysis population,” the investigators said.