Prediction of hypertension in chronic hemodialysis patients

Background. There are no universally accepted criteria for the diagnosis of hypertension in hemodialysis (HD) patients. We sought to determine the clinical performance of predialysis and postdialysis systolic and diastolic blood pressure values (BPs) in diagnosing hypertension or assessing its control. Methods. Seventy patients [77% African American, 46% females, mean age 59 +/- 17 (SD) years, 34% diabetics] on chronic HD underwent a single 44-hour interdialytic ambulatory blood pressure monitoring (ABPM) and concomitant recording of BP by conventional syphygmomanometer in the HD unit for two weeks. Hypertension was defined as systolic BP (SBP) greater than or equal to 135 mm Hg or diastolic BP (DBP) greater than or equal to 85 mm Hg on an average 44-hour ABPM. Results. Average ABP was 144 +/- 22/81 +/- 11 mm Hg. Seventy-three percent of the patients had systolic hypertension; 40% had diastolic hypertension, and 24% were normotensive or had well-controlled BP. Area under the curve of receiver operating characteristic (ROC) curves exceeded 80% for all BPs, but the thresholds for best sensitivity and specificity were markedly different for predialysis and postdialysis BPs. A two-week averaged predialysis BP of > 150/85 mm Hg or a postdialysis BP of >130/75 mm Hg had at least 80% sensitivity in diagnosing hypertension. Specificity of at least 80% was achieved if predialysis BP of > 160/90 mm Hg or postdialysis BP of > 140/80 mm Hg was used. There was poor agreement between HD unit BP and ABP values. Conclusions. HD unit BP values can be used to identify the presence or absence of hypertension, although prediction of ambulatory BPs from HD unit BP values cannot be made reliably in individual patients.