Effect of Ambient Temperature on Intradialytic Hypotension in Hemodialysis Patients: A Retrospective Cohort Study

This study aimed to investigate the effect of ambient temperature on intradialytic hypotension (IDH) in hemodialysis (HD) patients.

A single-center retrospective cohort study.

Patients receiving HD at the HD center at Shanghai Sixth People's Hospital between January 1, 2022, and May 31, 2025.

Ambient temperature and demographics (age, sex, dry weight, predialysis systolic blood pressure (SBP), interdialytic weight gain, HD shifts, modalities, dialysate calcium concentration, and ultrafiltration rate) were primary and secondary predictors.

The primary outcome of this study was IDH.

Pearson χ² tests for categorical variables and t test for continuous variables. Logistic regression was used to analyze IDH risk per temperature bin relative to the highest.

We collected 946,703 blood pressure records from 149,273 HD sessions. IDH occurred in 5,073 sessions, accounting for a prevalence of 3.4%. Compared with sessions at an ambient temperature of 33.5-35.5 °C, HD patients had a 2-fold higher risk of IDH when the ambient temperature was less than or equal to -0.5 °C. Furthermore, each 2 °C decrease in ambient temperature was associated with a 4.4% increase in IDH risk. Sensitivity analyses indicated that 21.5 °C as the temperature threshold shows the risk difference under the Nadir90/100 definition. The 3-way interaction indicated that patients with predialysis SBP ≥ 140 mm Hg and UFR ≤ 500 mL in spring and summer have the lowest intradialytic IDH risk. In addition, the analysis identified age, sex, HD shifts, predialysis SBP, interdialytic weight gain, dialysate calcium concentration, ultrafiltration rate, and season as independent risk factors for IDH.

A single-center, retrospective, and observational study design, not considering indoor temperature, inconsistent threshold analysis results, and ambiguity risk factors.

Lower ambient temperatures significantly increase the risk of IDH occurrence. Clinical staff should integrate ambient temperature, patient characteristics, and HD parameters into risk assessments to enhance early prevention, monitoring, and intervention of IDH.