Targeted strategies for managing seasonal blood pressure swings in high-risk hemodialysis patients

OBJECTIVE: To examine the subgroup characteristics of seasonal blood pressure (BP) fluctuations in maintenance hemodialysis (MHD) patients and to evaluate their association with cardiovascular and cerebrovascular events (CCVE). METHODS: A total of 154 eligible MHD patients treated at our center between May 2018 and October 2021 were retrospectively enrolled with informed consent. Systolic (SBP) and diastolic (DBP) BP values were collected and analyzed across different seasons, stratified by sex, age, and primary disease. The seasonal distribution of intradialytic hypertension, intradialytic hypotension, CCVE incidence, and mortality was further assessed. The interaction between season, age, and gender on BP was analyzed after using a multi-factor nonlinear mixed effects model, to correct for antihypertensive drug prescription, ultrafiltration rate, and dry body weight fluctuations. RESULTS: BP demonstrated significant seasonal variation (P < 0.05), with the lowest SBP and DBP observed in summer and the highest in winter, while spring and autumn showed intermediate values. Across all seasons, BP rose progressively with age: SBP and DBP were significantly higher in the 45-60 year group compared with < 45 years (P < 0.05), and highest in patients > 60 years (P < 0.05). Male patients consistently exhibited higher SBP and DBP than females in both warm (spring-summer) and cold (autumn-winter) seasons (P < 0.05). Compared with spring-summer, autumn-winter was associated with a higher proportion of intradialytic hypertension (37.66% vs. 20.78%, P < 0.01), a lower proportion of intradialytic hypotension (13.64% vs. 29.22%, P < 0.001), and increased CCVE incidence (22.73% vs. 11.69%) and mortality (7.79% vs. 3.25%, both P < 0.05). The amplitude of seasonal SBP fluctuation was greatest in patients > 60 years (19.72 ± 6.13 mmHg) compared with 45-60 years (14.13 ± 4.92 mmHg) and < 45 years (8.52 ± 3.21 mmHg, all P < 0.05). Male patients also showed larger SBP fluctuations than females (16.82 ± 5.73 mmHg vs. 11.53 ± 4.82 mmHg, P < 0.001), while no significant differences were observed among subgroups stratified by primary disease (P > 0.05). After multi-factor model correction, the interaction between season and age (P = 0.018) and season and gender (P = 0.025) remained significant, indicating that the seasonal increase in BP in elderly and male patients was independent effect of antihypertensive medication adjustment, ultrafiltration rate, and dry body weight fluctuations. CONCLUSION: BP in MHD patients was jointly influenced by season, age, and sex. The highest values and greatest fluctuations occurred in autumn-winter, in males, and in patients > 60 years. These subgroups represented high-risk populations for adverse cardiovascular and cerebrovascular outcomes during colder months. Targeted, season- and subgroup-specific BP management strategies might have helped mitigate CCVE risk and improve survival in MHD patients.