Association of peridialytic, intradialytic, scheduled interdialytic and ambulatory BP recordings with cardiovascular events in hemodialysis patients

Background Ambulatory-BP-monitoring (ABPM) is recommended for hypertension diagnosis and management in hemodialysis patients due to its strong association with outcomes. Intradialytic and scheduled interdialytic BP recordings show agreement with ambulatory BP. This study assesses in parallel the association of pre-dialysis, intradialytic, scheduled interdialytic and ambulatory BP recordings with cardiovascular events. Methods We prospectively followed 242 hemodialysis patients with valid 48-h ABPMs for a median of 45.7 months to examine the association of pre-dialysis, intradialytic, intradialytic plus pre/post-dialysis readings, scheduled interdialytic BP, and 44-h ambulatory BP with outcomes. The primary end-point was a composite one, composed of cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, resuscitation after cardiac arrest, hospitalization for heart failure, coronary revascularization procedure or peripheral revascularization procedure. Results Cumulative freedom from the primary end-point was significantly lower with increasing 44-h SBP (group 1, < 120 mmHg, 64.2%; group 2, >= 120 to < 130 mmHg 60.4%, group 3, >= 130 to < 140 mmHg 45.3%; group 4, >= 140 mmHg 45.5%; logrank-p = 0.016). Similar were the results for intradialytic (logrank-p = 0.039), intradialytic plus pre/post-dialysis (logrank-p = 0.044), and scheduled interdialytic SBP (logrank-p = 0.030), but not for pre-dialysis SBP (logrank-p = 0.570). Considering group 1 as the reference group, the hazard ratios of the primary end-point showed a gradual increase with higher BP levels with all BP metrics, except pre-dialysis SBP. This pattern was confirmed in adjusted analyses. An inverse association of DBP levels with outcomes was shown with all BP metrics, which was no longer evident in adjusted analyses. Conclusions Averaged intradialytic and scheduled home BP measurements (but not pre-dialysis readings) display similar prognostic associations with 44-h ambulatory BP in hemodialysis patients and represent valid metrics for hypertension management in these individuals.