Kidney function and risk of heart failure in older adults: findings from a prospective cohort study.

Background: We examined whether impaired kidney function, identified through elevated levels of urine albumin to creatinine ratio (UACR) or reduced estimated glomerular filtration rate (eGFR), is associated with hospitalisation or death due to heart failure (HF) in a large community-based cohort of older adults.

Methods: We included 17 834 participants from the ASPirin in Reducing Events in the Elderly (ASPREE) clinical trial and follow-up ASPREE eXTension observational study with complete baseline data on albuminuria and eGFR. HRs for hospitalisation due to HF (HHF), HF death, a composite outcome of HHF and HF death, and HF re-admission were calculated using Cox models adjusting for potential confounders.

Results: Over a median follow-up of 8.6 years, 354 (1.98%) participants had a first hospitalisation for HF and 147 (0.82%) died due to HF. Participants with albuminuria (UACR ≥3.0 mg/mmol; 11.3%) had higher risk for HHF, HF death and the combined HF outcome compared with those with no albuminuria (HRs 1.47 (95% CI 1.12 to 1.92), 1.55 (95% CI 1.04 to 2.33) and 1.33 (95% CI, 1.05 to 1.70), respectively). In participants with albuminuria, there was also an increased risk for re-admission due to HF (HR 1.30 (95% CI 1.03 to 1.65)), although there was no difference in risk of HF death. For eGFR, a U-shaped relationship was observed with increased risk of HHF, HF death and the HF composite outcome at both low (eg, <60 mL/min/1.73 m²) and high (eg, >90 mL/min/1.73 m²) eGFR levels. However, the association at high eGFR was not statistically significant and may reflect residual confounding. No association was observed between eGFR and HF re-admission.

Conclusions: In this large cohort of older adults, albuminuria was associated with increased risk of HF outcomes, supporting its role in HF risk assessment. Low eGFR was also linked to higher risk of HHF, HF death and the HF composite outcome. Associations with high eGFR were not conclusive and should be considered hypothesis-generating.