Dialysis dose and the diagnosis of hypertension in hemodialysis patients.

OBJECTIVE

To determine whether simultaneous consideration of pre and postdialysis blood pressure (BP) can improve the prediction of interdialytic ambulatory BP in hemodialysis patients, we analyzed BP obtained before and after dialysis using routine or standardized methods and by self-measurement at home in 104 hemodialysis patients. Evidence for effect modification was tested for several plausible demographic, clinical and laboratory factors.

RESULTS

Postdialysis BP when considered jointly with predialysis BP improved the diagnostic performance of standardized dialysis unit BP measurements [receiver operating characteristic (ROC) area under the curve (AUC) 0.91 for joint, 0.85 for prehemodialysis ROC (P=0.01 for difference in AUC)]. A trend to improvement existed in ROC AUC with routine dialysis unit BP measurement [ROC AUC 0.88 for joint, 0.82 for prehemodialysis ROC (P=0.055 for difference in AUC)]. Dialysis dose measured by urea reduction ratio was a strong effect modifier for the determination of hypertension by routine (P=0.012) and standardized (P=0.002) dialysis unit BP measurements. This effect modification was not seen with home BP (P=0.26).

CONCLUSION

Simultaneous consideration of predialysis and postdialysis BPs obtained over 2 weeks can improve the diagnosis of hypertension in hemodialysis patients. Dialysis dose may significantly influence the diagnosis of hypertension when dialysis unit BPs are used.