Home versus routine dialysis-unit blood pressure recordings among patients on hemodialysis

Abstract

The optimal method for the diagnosis of hypertension among patients on hemodialysis remains a controversial issue. Using 44-h ambulatory blood pressure (BP) monitoring (ABPM) as the reference-standard, we assessed the diagnostic performance of home BP monitoring (HBPM) versus routine dialysis-unit BP recordings in hemodialysis patients. Over a period of 2 weeks, the following methods were used for the assessment of hypertension: (i) routine predialysis and postdialysis BP recordings averaged over 6 consecutive dialysis sessions; (ii) HBPM for 7 days (duplicate morning and evening measurements, Microlife WatchBP Home N); (iii) 44-h ABPM (20-min intervals over an entire interdialytic interval, Microlife WatchBPO3). The study included 70 patients (mean age: 65.3 ± 13.2 years; treated hypertensives: 87.1%; 44-h ambulatory systolic/diastolic BP: 120.6 ± 15.2/66.3 ± 10.1 mmHg). Mean (standard deviation) of the differences between ambulatory daytime systolic BP (SBP) and routine predialysis SBP was -11.4 (13.4) mmHg, routine postdialysis SBP -4.0 (15.1) mmHg and home SBP -8.6 (10.7) mmHg. The area under the receiver-operating-characteristic-curve (AUC) for the detection of an ambulatory daytime SBP ≥ 135 mmHg was higher for home SBP [AUC: 0.934; 95% confidence interval (CI): 0.871-0.996] relative to predialysis SBP (AUC: 0.778; 95% CI: 0.643-0.913) and postdialysis SBP (AUC: 0.766; 95% CI: 0.623-0.909) (P = 0.02 for both comparisons). Home SBP at the cut-off point of 141.0 mmHg provided the best combination of sensitivity (85.7%) and specificity (92.9%) in diagnosing hypertension. In conclusion, the present study shows that among hemodialysis patients, HBPM for 1 week is superior to 2-week averaged routine predialysis or postdialysis BP in predicting ambulatory hypertension.