Controlling blood pressure in hemodialysis patients is crucial but not always easy. The most common blood pressure measurement method is peri-dialysis measurement, but due to interdialytic blood pressure fluctuations, we are unsure if it is the proper way for evaluating blood pressure. Some studies have shown the superiority of 24-h ambulatory blood pressure monitoring over peri-dialysis blood pressure measurement. We aimed to compare the consistency of these methods in determining hypertension among hemodialysis patients. We studied 50 patients (mean age: 55.8 years) on regular hemodialysis in Imam Khomeini University Hospital, Tehran, Iran. Peri-dialysis blood pressure and interdialytic 24-h ambulatory blood pressure monitoring were recorded for each patient. Patients' demographic data and peri-dialysis weight were recorded too. All data were analyzed using the PASW Statistics 18.0, SPSS Inc. (Chicago, IL). There was a significant difference between pre-dialysis mean systolic blood pressure (146.1 ± 23.3 mmHg) and mean systolic blood pressure recorded by ambulatory blood pressure monitoring (135.3 ± 19.3 mmHg) (p = 0.001). There was also a significant difference between pre-dialysis mean diastolic blood pressure (83 ± 14 mmHg) and mean diastolic blood pressure recorded by ambulatory blood pressure monitoring (77.3 ± 10 mmHg) (p = 0.003). But the frequencies of hypertension measured with both methods were significantly consistent and the Kappa agreement coefficient was 0.525 (p = 0.001). Considering ambulatory blood pressure monitoring as the gold standard for blood pressure measurement, our recommendation for the best cutoff point to diagnose hypertension, with the highest sensitivity and specificity would be 135/80 mmHg for pre-dialysis blood pressure and 115/70 mmHg for post-dialysis blood pressure.
Keywords: Ambulatory blood pressure monitoring; hemodialysis; hypertension; peri-dialysis blood pressure.