Reproducibility of ambulatory blood pressure monitoring in hemodialysis patients

Ambulatory blood pressure monitoring (ABPM) has been increasingly used in h emodialysis (HD) practice and research; however, no study has evaluated the reproducibility of ABPM in this population. To address this question, we p erformed 48-hour interdialytic ABPM on 21 HD patients (mean age, 53 +/- 16 years; 7 women) on two different occasions 68 +/- 34 days (range, 30 to 154 days) apart. To qualify for the protocol, patients had to be at the same d ry weight and on the same vasoactive drug regimen at both monitoring period s. BP was analyzed according to three different methods: isolated pre-HD an d post-HD values, average pre-HD and post-HD values for the five HD session s surrounding each monitoring period, and 48-hour interdialytic ABPM, Repro ducibility was determined by analysis of the SD of the differences (SDD) be tween the two monitoring periods and the coefficient of variation of each m ethod of BP determination. Our results show better reproducibility of ABPM (SDD, 10.6/6.6 mm Hg; coefficient of variation, 7.5%/8.1%) compared with is olated pre-HD BP (SDD, 24.4/11.3 mm Hg; coefficient of variation, 16.7%/14. 1%) or post-HD BP (SDD, 16.8/14.5 mm Hg; coefficient of variation, 11.7%/17 .8%), and averaged pre HD BP (SDD, 14.7/7.2 mm Hg; coefficient of variation , 10.1%/9.1%) or post-HD BP (SDD, 12.4/8.7 mm Hg; coefficient of variation, 8.9%/11.1%). The reproducibility of the decrease in BP during sleep was po or, with up to 43% of the subjects changing dipping category within or betw een interdialytic periods. We conclude that ABPM is the most accurate metho d to study BP in HD patients over time. However, variability is significant , and there is poor reproducibility of the nocturnal decline in BP. (C) 200 0 by the National Kidney Foundation, Inc.