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Abstract: PO2353

Lower Serum Bicarbonate Is a Risk Factor for Hospitalization for Infection Among Patients with CKD

Session Information

Category: CKD (Non-Dialysis)

  • 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

  • Saly, Danielle L., Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Strohbehn, Ian Austin, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Sise, Meghan E., Massachusetts General Hospital, Boston, Massachusetts, United States
  • Curhan, Gary C., Brigham and Women's Hospital, Boston, Massachusetts, United States
Background

Hospitalization due to infection is common in patients with CKD; both lower eGFR and albuminuria are risk factors. Metabolic acidosis impairs neutrophil function in ESRD patients via delayed apoptosis, enhanced phagocytosis, and increased oxidative burst reactions, however serum bicarbonate has not been investigated as a risk factor for infection in patients with non-dialysis CKD.

Methods

We utilized a central data warehouse from Mass General Brigham for patients with ≥1 diagnostic code for CKD between 2010-2020. CKD was defined as 2 outpatient eGFR values <60 mL/min/1.73m2 at least 3 months apart. Patients were excluded if they had a kidney transplant, a humoral immunodeficiency, or ESRD on dialysis prior to index date. The primary outcome was hospitalization for infection (defined by primary diagnosis of urinary tract infection/ pyelonephritis, pneumonia, cellulitis, or bacteremia). We examined outpatient baseline serum bicarbonate and risk of initial hospitalization for infection using Cox proportional hazards models adjusting for potential confounders. Patients were censored at time of first infection, last lab value, or death.

Results

We included 36,647 patients with CKD, and 8,521 were hospitalized for infection. When adjusting for covariates, the risk for infection increased as serum bicarbonate decreased (Figure 1). A serum bicarbonate of <20 mEq/L compared to ≥28 mEq/L was independently associated with an 18% (95% CI 1.05-1.32) higher risk of hospitalization. In the adjusted model, CKD stage 5 was associated with a 69% (95% CI 1.47-1.94) increased risk of infection compared to CKD stage 3a. Albuminuria ≥300 mg/g was associated with a 28% (95% CI 1.14-1.44) increased risk of composite infection compared to <10 mg/g.

Conclusion

Our findings suggest that clinicians should consider lower serum bicarbonate a risk factor for infection in patients with CKD. Future studies should explore whether bicarbonate supplementation can reduce risk of infection.

Funding

  • NIDDK Support