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Abstract: PO1163

The Association of Body Mass Index with the Development of Metabolic Acidosis in Patients with CKD

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

  • 902 Fluid, Electrolyte, and Acid-Base Disorders: Clinical


  • Reaven, Nancy L., Strategic Health Resources, La Canada, California, United States
  • Funk, Susan E., Strategic Health Resources, La Canada, California, United States
  • Mathur, Vandana S., MathurConsulting, Woodside, California, United States
  • Ferguson, Thomas W., Division of Nephrology, University of Manitoba, Winnipeg, Manitoba, Canada
  • Tangri, Navdeep, Division of Nephrology, University of Manitoba, Winnipeg, Manitoba, Canada

Bone is the largest body buffer and body mass index (BMI) is directly related to bone mass. We explored the relationship between BMI and incident metabolic acidosis in patients with CKD.


Optum’s de-identified Integrated Claims-Clinical dataset of US patients (2007-2019) was queried to identify patients with non-dialysis CKD stages 3-5 with 2 consecutive serum bicarbonate values in the normal range (22 to <30 mEq/L), 28–365 days apart, with data ≥12 months pre-index during which covariates were assessed. The first qualifying serum bicarbonate test established the index date. The primary exposure variable was BMI category (World Health Organization classification). Other exposures included hypertension diagnosis, triglycerides ≥1.7 mmol/L, HDL cholesterol ≤1 mmol/L in women or ≤0.9 mmol/L in men. Adjusted Cox Proportional Hazards models were performed to evaluate the time to development of new-onset metabolic acidosis (serum bicarbonate 12 to <22 mEq/L) over a follow-up period of ≤11.5 years. Other covariates included age, sex, race, education and income status, diabetes or heart failure, eGFR, log albumin-to-creatinine ratio, angiotensin converting enzyme inhibitors or angiotensin receptor blockers prescription, and diuretic prescription.


97,294 patients qualified for this study. There was an inverse association between BMI category and the risk of developing metabolic acidosis. Compared to BMI category of 18.5-25, each incremental category of higher BMI was associated with a decreasing risk of developing metabolic acidosis: BMI 25 to <30, HR 0.866, 95% CI: 0.824-0.911; BMI 30 to <35, HR 0.770, 95% CI: 0.729-0.813; BMI 35 to <40, HR 0.664, 95% CI: 0.622-0.709; BMI 40+, HR 0.612, 95% CI: 0.571-0.655. Additionally, hypertension decreased and low HDL cholesterol and elevated triglycerides increased the risk of new-onset metabolic acidosis.


In this large cohort of patients with CKD, an incremental increase in BMI was inversely associated with the development metabolic acidosis. The mechanism of this association merits further study.


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