Predialysis serum phosphate and intradialytic hypotension

Abstract

Introduction: Intradialytic hypotension (IDH) is a common complication of hemodialysis (HD) and is associated with excess morbidity and mortality. Higher serum phosphate is associated with adverse cardiovascular outcomes in maintenance HD patients; however, its association with IDH has not previously been assessed. Methods: This is an analysis of a prospective cohort of 969 HD patients (80,968 HD sessions) receiving HD at a large dialysis organization (LDO) and a post-hoc analysis of 1838 HD patients (10,594 HD sessions) in the Hemodialysis study (HEMO), a multicenter randomized controlled trial that examined standard or high-dose HD and low-flux or high-flux membranes. Unadjusted and adjusted mixed effects regression models were fit to determine the association of pre-HD serum phosphate with IDH, defined as a nadir intra-HD systolic blood pressure (SBP) <90 mmHg.Findings: In the LDO cohort, baseline mean pre-HD serum phosphate was 5.2 AE 1.7 mg/dl. IDH occurred in 15.6% of HD sessions. In the adjusted model, higher pre-HD serum phosphate (per 1 mg/dl) was associated with a 12% increased risk of IDH (aOR 1.12, 95% CI 1.10-1.13, p <0.001). In exploratory models where pre-HD laboratory values were available, the effect estimate was attenuated but remained statistically significant (aOR 1.05; 95% CI 1.02-1.08; p <0.01). Participants in the highest (compared with the lowest) quartile of pre-HD serum phosphate had a 56% greater risk of IDH in the adjusted model (aOR Q4:Q1 1.56; 95% CI 1.44-1.68, p <0.001). The association of higher phosphate with IDH was consistent in the HEMO data.Discussion: Higher pre-HD serum phosphate is independently associated with an increased risk of IDH. As HD may cause an acute decline in serum phosphate, future studies to investigate the mechanisms of this association are warranted.

Circumferential Strain as a Marker of Vessel Reactivity in Patients with Intradialytic Hypotension

“…BP decline occurs due to a decrease in cardiac output and arterial tone, which are caused by insufficient response and/or impairment of compensatory mechanisms (cardiac, plasma refilling, passive venoconstriction, and an active increase in arterial tone) during HD [ 10 ]. Risk factors for IDH are both modifiable and non-modifiable, such as age >65 years, higher body mass index (BMI), female sex, cardiovascular disease, arrythmia, diabetes mellitus, vascular calcification (VC), hypoalbuminemia, hyperphosphatemia, anemia, higher ultrafiltration rate (UFR) and higher interdialytic weight gain (IDWG) [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. An occurrence of IDH may depend on the composition of dialysate, e.g., sodium concentration and sodium profiling [ 20 , 21 ], concentration of calcium ions [ 22 , 23 ], bicarbonate [ 22 ] and temperature [ 21 , 24 ].…”