Impact of barometric pressure on blood pressure during dialysis: Introducing intradialytic time-averaged cumulative systolic blood pressure (TACsBP-inD) as a new metric

Abstract

Background: Blood pressure is a crucial risk factor for hemodialysis patients, but the specific impact of weather factors, particularly barometric pressure, on blood pressure remains unclear. This study aims to examine the relationship between barometric pressure and blood pressure in hemodialysis patients.

Methods: We conducted a single-center, retrospective study involving 122 hemodialysis patients in Japan, covering the period from August 2018 to October 2022. In addition to standard blood pressure indices, for the purpose of a more accurate assessment, we introduced the intradialytic time-averaged cumulative systolic blood pressure (TACsBP-inD). Multilevel mixed-effects linear regression models with random intercepts for each patient and spline analyses were used to evaluate the association between barometric pressure and blood pressure.

Results: Our analysis demonstrated a positive correlation between barometric pressure and various intradialytic blood pressure indices, including TACsBP-inD, in both univariate and multivariate models. Spline analyses revealed a U-shaped relationship between barometric pressure and TACsBP-inD. Furthermore, categorized barometric pressure showed significantly positive coefficients for TACsBP-inD at both lower and higher pressure ranges, supporting the U-shaped trend. Subgroup analyses revealed that this positive association was not observed at lower pressures among males, obese individuals, and patients with diabetes, cardiovascular disease, and smoking habits, suggesting that blood pressure responses vary depending on patient profiles.

Conclusions: These findings emphasize the significant impact of barometric pressure on intradialytic blood pressure, suggesting that atmospheric conditions could be an important consideration in blood pressure management for hemodialysis patients.

Keywords: barometric pressure; blood pressure; hemodialysis; weather.

FIGURE 1

Schematic illustration of TACsBP‐inD. During a hemodialysis session, sBP readings at two consecutive time points were averaged, then multiplied by the duration between these points. This product was accumulated over the session. The final value was obtained by dividing the total accumulated value by the total duration of the treatment.

FIGURE 2

Relationship between barometric pressure and blood pressure. Spline curves for barometric pressure with TACsBP‐inD (A), average mean blood pressure (B), maximum sBP (C), minimum sBP (D), pretreatment sBP (E), and posttreatment sBP (F) are shown. The shaded area indicates a 95% confidence interval.

FIGURE 3

Changes in barometric pressure and TACsBP‐inD during the passage of Typhoon Francisco and Typhoon Krosa. The changes in TACsBP‐inD (closed circles) and barometric pressure (open circles) over August 2019 are shown. The x‐axis denotes the date, while the left y‐axis represents TACsBP‐inD and the right y‐axis represents barometric pressure. Error bars represent standard errors. The dates when Typhoon Francisco (August 6, 2019) and Typhoon Krosa (August 15, 2019) passed through Miyazaki City are marked with black arrows. Pairwise comparisons showed a significant difference between August 3 and August 15 (p < 0.05).

FIGURE 4

Association between categorical barometric pressure and TACsBP‐inD. The relationship between categorical barometric pressure values and TACsBP‐inD was examined. In both univariate and multivariate regression models, the ranking of the coefficients was as follows: Q4 > Q3 > Q1 > Q2.