Seasonal decreases in 24-hour systolic blood pressure from winter to summer were associated with significant declines in eGFR among older adults (β=2.72; 95% CI 1.94-3.54; P<0.001).
Cohort (n=166)
Does seasonal decline in blood pressure, particularly nighttime systolic blood pressure, associate with reduced kidney function in older adults?
Seasonal declines in blood pressure, specifically nighttime systolic blood pressure, are independently associated with reductions in kidney function among older adults.
Effect estimate: β 2.72 (95% CI 1.94-3.54)
p-value: p=< 0.001
Objective: Blood pressure (BP) exhibits seasonal variation, increasing in winter and decreasing in summer. Renal function is also known to worsen during the summer. However, most previous reports have been based on clinic BP measurements, and few studies have investigated seasonal variations in BP assessed by ambulatory blood pressure monitoring (ABPM), their association with renal function, or the reproducibility of these findings. Design and method: We analyzed data from a 166 outpatient clinic cohort of older adults (mean age 74.5±7.4 years) assessed in winter and summer of 2021 and 2022, with ABPM performed at each visit. Changes in BP and estimated glomerular filtration rate (eGFR) were calculated as the difference between winter and summer values. Associations between 1-standard-deviation (SD) changes in BP and changes in eGFR were evaluated using multivariable linear regression adjusted for age, sex, body mass index, and baseline chronic kidney disease status. Results: The mean 24-hour BP in this cohort was 113.5±8.8/67.1±5.9 mmHg. From winter to summer 2021, 1-SD decreases in 24-hour SBP were associated with eGFR decline (β= 2.72, 95% CI 1.94–3.54, P < 0.001), with similar associations for daytime, nighttime, and morning SBP. In winter-to-summer 2022, associations were observed only for 24-hour and nighttime SBP. In simultaneous models, nighttime SBP had a stronger independent association than daytime SBP (winter-to-summer 2021: daytime β = 1.06, 95% CI 0.10–2.02, P = 0.031; nighttime β = 2.18, 95% CI 1.21–3.14, P < 0.001). Associations were consistent regardless of antihypertensive use. Conclusions: Seasonal declines in BP, particularly nighttime SBP, are associated with reductions in kidney function among older adults. Monitoring and managing nighttime BP fluctuations may help preserve renal function in this population.
Nishizawa et al. (Fri,) conducted a cohort in Older adults (n=166). Seasonal decrease in blood pressure was evaluated on Change in estimated glomerular filtration rate (eGFR) associated with a 1-SD decrease in 24-hour SBP (β 2.72, 95% CI 1.94-3.54, p=< 0.001). Seasonal decreases in 24-hour systolic blood pressure from winter to summer were associated with significant declines in eGFR among older adults (β=2.72; 95% CI 1.94-3.54; P<0.001).