# Intradialytic Hypotensive Episodes are Only Occasionally Associated With Adverse Symptoms

## TL;DR

Intradialytic hypotension during dialysis is mostly asymptomatic and rarely linked to reported symptoms or outcomes.

## Contribution

This study shows that asymptomatic intradialytic hypotension is much more common than previously thought based on symptom-based definitions.

## Key findings

- 98% of intradialytic hypotension episodes were asymptomatic.
- Only 4 out of 24 reported symptoms met threshold criteria for IDH.
- No strong association was found between IDH and patient-reported outcomes.

## Abstract

Although intradialytic hypotension (IDH) is a frequent complication of hemodialysis (HD), a consensus definition is lacking. Adverse symptoms and/or interventions are a prerequisite in guidelines; however, a threshold-based blood pressure (BP) definition appeared most strongly associated with mortality. In this study, we evaluated the association of IDH with both real-time symptoms and physical intradialytic patient-reported outcome measures (PID-PROMs) in prevalent HD and hemodiafiltration (HDF) patients.

This is a secondary analysis of the HOLLANT study, a randomized cross-over trial comparing 4 dialysis modalities (i.e., standard HD, cool high-flux HD, low-volume HDF, and high-volume HDF), each applied for 2 weeks in 40 patients. In each second treatment week, BP was measured every 15 minutes and when symptoms occurred. Symptoms were documented real-time and PID-PROMs were collected after each modality. Considering that symptoms occurred independent of dialysis mode, data from all treatment modalities were pooled. IDH was threshold-defined (systolic BP [SBP] < 90 or < 100 mm Hg, dependent on predialysis SBP). The incidence of symptomatic IDH (sIDH) and asymptomatic IDH (aIDH) was assessed, with sIDH defined by concurrent symptoms. When real-time symptoms arose, attribution to IDH was appraised according to the threshold, National Kidney Disease Outcomes Quality Initiative, and the European Best Practice Guideline definitions. Differences in PID-PROMs were analyzed in tertiles of IDH occurrence.

In 20.1% of 458 treatments, 222 IDH episodes were observed (0.48/session). The majority occurred toward the end of dialysis and 98% was asymptomatic. Real-time reported symptoms (n = 24) were noted in 5.2% of the sessions. Although half were BP-related (n = 13/24), just 4 fulfilled the threshold criteria. Associations between IDH and PID-PROMs were largely absent.

aIDH exceeds sIDH by far. Therefore, symptom-based definitions severely underestimate aIDH incidence. Both real-time occurring symptoms and PID-PROMs are only occasionally associated with IDH.