Methods: This was a sub-analysis of a prospective cohort study on 50 maintenance, thrice-weekly HD patients admitted to Brigham and Women's Hospital in Boston, MA, USA.The analysis included 20 patients in whom OH was assessed 5 to 60 mins before HD by measuring BP (using a calibrated upper-arm cuff) in the supine position (after at least 5 mins of rest) and then at 1, 3, and 5 mins after standing.OH was defined as a decrease in systolic BP (SBP) by at least 20 mmHg or below 90 mmHg, or a decrease in diastolic blood pressure (DBP) by at least 10 mmHg, within 3 minutes of standing.In patients with baseline supine SBP>140 mmHg, a threshold decline of 30 mmHg was used.In 5 patients who were unable to stand, BP was measured in the sitting position.BP was then measured before and every 15 min during subsequent HD (lasting approximately 4 hours).Results: Of the 20 studied patients (9 females), median age was 65 years, and median BP in the supine position was 135/63 mmHg.Predialysis OH was observed in 12 patients (60%, 5 females), including 4 patients who sat instead of standing up.No significant differences were found between the OH and non-OH groups in terms of supine BP, age, diagnosis of hypertension, heart failure, or diabetes, BP medications, or dialysis prescription parameters.Patients from the OH group tended to have lower DBP before and throughout HD and lower SBP during most of HD (see Figure 1); however, significant differences were found only for DBP before HD (median 65 mmHg in the OH group vs 80 mmHg in the non-OH group, P=0.049) and for DBP at 120 min into HD (57 mmHg vs 76 mmHg, P=0.048).In the non-OH group, SBP remained relatively stable through most of HD and only decreased significantly after around 165 min (median 124 vs 136 mmHg pre-HD, P=0.03).In the OH group, SBP showed a significant decrease during HD already after 30 min (129 vs 144 mmHg pre-HD, P=0.02) and a further decrease after 120 min (104 vs 134 mmHg pre-HD, P=0.03).
Tafoya et al. (Wed,) studied this question.