Prevalence and control of hypertension by 48-h ambulatory blood pressure monitoring in haemodialysis patients: a study by the European Cardiovascular and Renal Medicine (EURECA-m) working group of the ERA-EDTA

BACKGROUND: Population-specific consensus documents recommend that the diagnosis of hypertension in haemodialysis patients be based on 48-h ambulatory blood pressure (ABP) monitoring. However, until now there is just one study in the USA on the prevalence of hypertension in haemodialysis patients by 44-h recordings. Since there is a knowledge gap on the problem in European countries, we reassessed the problem in the European Cardiovascular and Renal Medicine working group Registry of the European Renal Association-European Dialysis and Transplant Association. METHODS: A total of 396 haemodialysis patients underwent 48-h ABP monitoring during a regular haemodialysis session and the subsequent interdialytic interval. Hypertension was defined as (i) pre-haemodialysis blood pressure (BP) ≥140/90 mmHg or use of antihypertensive agents and (ii) ABP ≥130/80 mmHg or use of antihypertensive agents. RESULTS: The prevalence of hypertension by 48-h ABP monitoring was very high (84.3%) and close to that by pre-haemodialysis BP (89.4%) but the agreement of the two techniques was not of the same magnitude (κ statistics = 0.648; P <0.001). In all, 290 participants were receiving antihypertensive treatment. In all, 9.1% of haemodialysis patients were categorized as normotensives, 12.6% had controlled hypertension confirmed by the two BP techniques, while 46.0% had uncontrolled hypertension with both techniques. The prevalence of white coat hypertension was 18.2% and that of masked hypertension 14.1%. Of note, hypertension was confined only to night-time in 22.2% of patients while just 1% of patients had only daytime hypertension. Pre-dialysis BP ≥140/90 mmHg had 76% sensitivity and 54% specificity for the diagnosis of BP ≥130/80 mmHg by 48-h ABP monitoring. CONCLUSIONS: The prevalence of hypertension in haemodialysis patients assessed by 48-h ABP monitoring is very high. Pre-haemodialysis BP poorly reflects the 48 h-ABP burden. About a third of the haemodialysis population has white coat or masked hypertension. These findings add weight to consensus documents supporting the use of ABP monitoring for proper hypertension diagnosis and treatment in this population.