Kidney Week

Abstract: TH-PO0327

Effect of Seasonal Variation on the Association Between Worsening Kidney Function and Outcomes Among Discharged Heart Failure Patients

Session Information

• Hypertension and CVD: Clinical - 1
  November 06, 2025 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Hypertension and CVD

• 1602 Hypertension and CVD: Clinical

Authors

• Oka, Tatsufumi, The University of Osaka, Suita, Osaka, Japan

Tatsufumi Oka, MD, PhD

• Tighiouart, Hocine, Tufts Medical Center, Boston, Massachusetts, United States

Hocine Tighiouart, MS

• McCallum, Wendy I., Tufts Medical Center, Boston, Massachusetts, United States

Wendy I. McCallum, MD, MS

• Tuttle, Marcelle, Tufts Medical Center, Boston, Massachusetts, United States

Marcelle Tuttle, MD

• Sakaguchi, Yusuke, The University of Osaka, Suita, Osaka, Japan

Yusuke Sakaguchi, MD, PhD

• Isaka, Yoshitaka, The University of Osaka, Suita, Osaka, Japan

Yoshitaka Isaka, MD, PhD

• Konstam, Marvin, Tufts Medical Center, Boston, Massachusetts, United States

Marvin Konstam

• Udelson, James, Tufts Medical Center, Boston, Massachusetts, United States

James Udelson, MD

• Sarnak, Mark J., Tufts Medical Center, Boston, Massachusetts, United States

Mark J. Sarnak, MD, MS

Background

While worsening kidney function is accepted as a risk factor for adverse heart failure (HF) outcomes, the effect of seasonal variation on its clinical significance remains unclear. We hypothesized that declines in kidney function in the summer, which may be partly volume and/or hemodynamic related and therefore more benign, may be less strongly associated with adverse outcomes in outpatient HF settings.

Methods

This post-hoc analysis of the Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial included patients discharged from a HF hospitalization. Based on discharge month, summer and winter were defined as June–August and December–February, respectively, in northern hemisphere locations, and vice versa in southern hemisphere locations. Spring/fall included the remaining months. Percent (%) eGFR decline was calculated as the difference between the lowest eGFR within 4 weeks after discharge and eGFR at discharge. The association between %eGFR decline and subsequent risk of the composite of cardiovascular mortality or HF re-hospitalization was evaluated using season-specific Cox regression models stratified by country. Models were adjusted for patient demographics, comorbidities, laboratory data, medications, and randomized group.

Results

Among 3,239 patients, 25.2% were women, and the mean (SD) age and eGFR at discharge were 65.5 (11.6) years and 60.8 (22.2) mL/min/1.73 m², respectively. Discharge eGFR and %eGFR decline within 4 weeks did not differ across seasons (P >0.30 for both). Over a median (IQR) follow-up of 32 (16–57) weeks, 1,115 composite outcome events occurred. A greater eGFR decline was significantly associated with an increased risk of the composite outcome overall, as well as in the winter and spring/fall, but not in the summer (P_interaction =0.02) (Figure).

Conclusion

A greater eGFR decline was associated with an increased risk of cardiovascular events in the winter and spring/fall but not in the summer among HF discharged patients.

Digital Object Identifier (DOI)

• doi: 10.1681/ASN.20255hss1z3t