Kidney Week

Abstract: FR-OR47

Urine Ammonium Concentrations and Cardiovascular and Kidney Outcomes in SPRINT

Session Information

• Hypertension, CVD, and the Kidneys: Clinical Studies
  October 25, 2024 | Location: Room 5, Convention Center
  Abstract Time: 04:40 PM - 04:50 PM

Category: Hypertension and CVD

• 1602 Hypertension and CVD: Clinical

Authors

• Bullen, Alexander L., University of California San Diego, La Jolla, California, United States

Alexander L. Bullen, MD, FASN

• Rifkin, Dena E., University of California San Diego, La Jolla, California, United States

Dena E. Rifkin, MD

• Ix, Joachim H., University of California San Diego, La Jolla, California, United States

Joachim H. Ix, MD, FASN

• Katz, Ronit, University of Washington, Seattle, Washington, United States

Ronit Katz, PhD

Background

Impaired urine ammonium excretion is common in chronic kidney disease (CKD) and may identify risk of metabolic acidosis earlier than reductions in serum bicarbonate or pH, and thus may have associations with cardiovascular disease (CVD) outcomes. We evaluated the association of urine ammonium with CVD and kidney outcomes among persons with hypertension and non-diabetic CKD enrolled in a trial of blood pressure reduction.

Methods

We measured urine ammonium concentration in spot urine specimens collected at baseline among 2092 participants. We used multivariable-adjusted Cox models to evaluate associations of urine ammonium concentration with the SPRINT primary CVD composite outcome (myocardial infarction, acute coronary syndrome, stroke, heart failure, or CVD death), all-cause mortality, the SPRINT kidney composite outcome (50% kidney function decline, end stage kidney disease, or transplant), and acute kidney injury (AKI).

Results

The mean (SD) age was 73 (9) years; 40% were female; and 25% were Black participants. The mean (SD) serum bicarbonate was 25.6 (2.8) mmol/L, median (interquartile range, IQR) urine ammonium concentration was 14.4 (9.5, 23.1) mmol/L, and median (IQR) eGFR was 49 (39,55) ml/min/1.73 m². There were 255 CVD composite events, 143 deaths, 63 kidney composite events, and 146 AKI events during a median follow-up of 3.8 years. In multivariable models, each 2-fold higher urinary ammonium concentration was associated with a 26% (95% CI 1.05, 1.52) higher risk of the CVD composite, whereas there was no association with all-cause mortality, the SPRINT kidney composite outcome, or AKI.

Conclusion

Among non-diabetic individuals with hypertension and CKD, higher urine ammonium concentration is associated with higher risk of CVD.

Funding

• Veterans Affairs Support