Abstract
BACKGROUND AND OBJECTIVES: Among people with essential hypertension, ambulatory BP measurement is superior to BP obtained in the clinic in predicting cardiovascular outcomes. In part, this is because it can detect white-coat hypertension and masked hypertension. Whether the same is true for hemodialysis patients is not known. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Using a threshold of 140/80 mmHg for median midweek dialysis-unit BP and 135/85 mmHg for 44-hour ambulatory BP, we defined four categories of BP: sustained normotension (SN), white-coat hypertension (WCH), masked hypertension (MHTN), and sustained hypertension (SHTN). RESULTS: Among 355 long-term hemodialysis patients, the prevalence of SN was 35%, WCH 15%, MHTN 15%, and SHTN 35%. Over a mean follow-up of 29.6 (SD 21.7) months, 102 patients died (29%), yielding a crude mortality rate of 121/1000 patient-years. Unadjusted and multivariate-adjusted analyses showed increasing all-cause mortality with increasing severity of hypertension (unadjusted hazard ratios from SN, WCH, MHTN, SHTN: 1, 1.12, 1.70, 1.80, respectively [P for trend < 0.01]; adjusted hazard ratios: 1, 1.30, 1.36, 1.87, respectively [P for trend 0.02]). When a predialysis BP threshold of 140/90 mmHg was used to classify patients into BP categories, the prevalence of SN was 24%, WCH 26%, MHTN 4%, and SHTN 47%. Hazard ratios for mortality were similar when compared with median midweek dialysis-unit BP. CONCLUSIONS: As in the essential hypertension population, MHTN and WCH have prognostic significance. The prognostic value of BP obtained in the dialysis unit can be refined with ambulatory BP monitoring.