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Abstract: PO1487

Anion Gap and Cardiovascular Mortality

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

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


  • Verma, Ashish, Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Subudhi, Sonu, Massachusetts General Hospital, Boston, Massachusetts, United States
  • Patel, Ankit B., Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Tio, Maria Clarissa, Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Waikar, Sushrut S., Boston University Medical Campus, Boston, Massachusetts, United States

Anion gap has been shown to be independently associated with hypertension, but the association of anion gap and cardiovascular mortality has been unexplored.


We conducted a prospective cohort study using the National Health and Nutrition Examination Survey (NHANES), a nationally representative cross-sectional survey of the US non-institutionalized population. Anion gap (mEq/L) was calculated as serum sodium (mmol/L) – (serum chloride (mmol/L) + serum bicarbonate (mmol/L). We used weighted Cox proportional hazards models to assess the associations between anion gap with cardiovascular specific mortality, as recorded by the National Death Index. Multivariable models were adjusted for demographics data, BMI, smoking status, diabetes, systolic blood pressure, cardiovascular disease history, ACEi/ARB, diuretics, serum albumin, total cholesterol, total protein, total calorie intake, hemoglobin, cancer diagnosis, eGFR and urine albumin and creatinine ratio.


This study was performed on 39,189 participants [mean (SD) age, 46.86 (19.25) years; 20,194 (51.5%) female. During 875 (4436210 weighted) person-years of follow-up, 936 participants (3169889 weighted participants) died of cardiovascular disease. A history of cardiovascular disease at the time of enrollment was reported in 3875 (9.8%). Figure 1 shows the associations between anion gap in tertiles with cardiovascular related mortality. In analyses restricted to those with a history of cardiovascular disease, results were 116% increased risk for cardiovascular mortality [HR 2.16;95% CI (1.37,3.4)].


Higher anion gap may be a risk factor for cardiovascular-related mortality in adults.

Figure 1. Risk of cardiovascular mortality according to anion gap as tertiles (method = weighted survey cox regression)