ACCURACY OF FIXED 24-H AMBULATORY BLOOD PRESSURE RECORDINGS FOR DIAGNOSING HIGH 44-H AMBULATORY BLOOD PRESSURE IN HEMODIALYSIS PATIENTS: A DIAGNOSTIC TEST STUDY

Abstract

Objective: Hypertension is highly prevalent in hemodialysis patients. Ambulatory-BP-monitoring (ABPM) during the 44-h interdialytic interval is recommended for hypertension diagnosis and management in these subjects. This study assessed the diagnostic accuracy of fixed 24-h ABPM recordings with 44-h BP in hemodialysis patients. Design and method: 242 Greek hemodialysis patients that underwent valid 48-h ABPM (Mobil-O-Graph NG device) were included in the analysis. We used 44-h BP used as reference method and tested the accuracy of the following BP metrics: 1st 24-h without HD period (20h-1st), 1st 24-h including HD period (24h-1st) and 2nd 24-h (24h-2nd). Results: All studied metrics showed strong correlations with 44-h SBP/DBP (20h-1st: r = 0.973/0.978, 24h-1st: r = 0.964/0.972 and 24h-2nd: r = 0.978/0.977, respectively). In Bland-Altman analysis, small between-method differences (-1.70, -1.19 and +1.45 mmHg) with good 95% limits-of-agreement ([-10.83 to 7.43], [-11.12 to 8.74] and [-6.33 to 9.23] mmHg, respectively) for 20h-1st, 24h-1st and 24h-2nd SBP were observed. The sensitivity/specificity and ↓-statistic for diagnosing 44-h SBP grater or equal to 130 mmHg were high for 20h-1st SBP (87.2%/96.0%, ↓-statistic = 0.817), 24h-1st SBP (88.7%/96.0%, ↓-statistic = 0.833) and 24h-2nd SBP (95.0%/88.1%, ↓-statistic = 0.837). Similar observations were made for DBP. In ROC-analyses, all studied BP metrics showed excellent performance with high Area-Under-the-Curve values (20h-1st: 0.983/0.992; 24h-1st: 0.984/0.987 and 24h-2nd: 0.982/0.989 for SBP/DBP respectively). Conclusions: Fixed 24-h ABPM recordings during either the first or the second day of interdialytic interval have high accuracy and strong agreement with 44-h BP in hemodialysis patients. Thus, ABPM recordings of either the first or the second interdialytic day could be used for hypertension diagnosis and management in these subjects.