Reliability of routine and standardized in-center blood pressure measurement in chronic hemodialysis patients in Dakar: a case control study

Background: Blood pressure (BP) measurement in the diagnosis and monitoring of hypertension continues to be a topic of debate. The objectives of this study were 1) to evaluate the performance of hemodialysis center BP measurements (routine and standardized BP measurements) in the diagnosis of ambulatory BP in chronic hemodialysis patients using 44h ambulatory BP monitoring (44h-ABPM) as the reference measurement; 2) to compare the performance of standardized and routine BP measurement; and 3) to evaluate the concordance between the values measured at the hemodialysis center and the BP values at 44h-ABPM. Methods: In this 23-month case control study including 56 patients followed in the hemodialysis units of Aristide Le Dantec Hospital (HALD) and Idrissa Pouye General Hospital (HOGIP), BP was measured by 3 methods: i) an automated measurement (OMRON®) carried out by health professional called routine BP measurement (RBPM) in pre and post dialysis; ii) the mean of five automated measurements in a patient isolated in a quiet room called standardized BP measurement (SBPM) before and after dialysis; iii) 44h-ABPM with the CONTEC® device. The hypertension was defined as BP ≥ 130/80 mmHg at 44h-ABPM. Results: Fifty-six (56) patients including 31 men (55%) with a mean age of 45.20 ± 13.64 years were included. Thirty-one patients (55%) were hypertensive at the 44h-ABPM. Pre-dialysis SBPM was significantly better than pre-dialysis RBPM (AUC [IC 95%], 0.881 [0.778-0.984]/0.785 [0.664-0.907], p=0.02) in detecting 44h ambulatory systolic BP (SBP) ≥ 130 mmHg. Post-dialysis SBPM was also outperformed post-dialysis RBPM (0.916 [0.843-0.988]/0.874 [0.782-0.965]) in detecting 44h ambulatory SBP ≥ 130 mmHg without statistically significant difference. Pre-dialysis SBPM outperformed pre-dialysis RBPM (0.882 [0.776-0.988]/0.878 [0.781-0.975] in detecting 44h ambulatory DBP ≥ 80 mmHg without statistically significant difference. Post-dialysis SBPM also outperformed post-dialysis RBPM (0.914 [0.832-0.996]/0.848 [0.743-0.952]) in detecting 44h ambulatory DBP ≥ 80 mmHg without statistically significant difference. Hemodialysis center measurements overestimate ambulatory BP at 44h-ABPM. Conclusion: Hemodialysis center measurements overestimate ambulatory BP despite excellent performance on ROC curve analysis. SBPM performs better than RBPM and in particular in the detection of a SBP ≥ 130 mmHg in the ambulatory setting. SBPM overestimates SBP less than RBPM.