Abstract 16135: Hyponatremia is Related to Higher 30-Day Rehospitalization and 1-Year Mortality Rates in Patients Admitted With an Acute Coronary Syndrome: TRACE-CORE

Abstract

Introduction: Although hospital survival rates are improving among patients admitted with an acute coronary syndrome (ACS), early readmission is common and 1-year survival remains less than optimal. Improved risk stratification during an index ACS admission could direct greater surveillance or transitional care interventions for vulnerable patient populations prior to discharge from the hospital. While hyponatremia is associated with adverse outcomes after acute decompensated heart failure, less is known about whether hyponatremia relates to key post-discharge outcomes in patients discharged from the hospital after an ACS. Hypothesis: Hyponatremia is associated with early readmission and 1-year mortality in hospital survivors of an ACS. Methods: Using data from TRACE-CORE (Transitions, Risks, and Actions in Coronary Events - Center for Outcomes Research and Education), a diverse cohort of 2,081 patients discharged after an ACS, we examined the associations of admission hyponatremia (serum sodium ≤ 134 mmol/L) with 30-day readmission and 1-year all-cause mortality. Results: Cohort mean age was 61 (SD 11.3) years, 34% were women and 19% non-white. Hyponatremia was present in 10.9% and patients with hyponatremia had more pre-existing hypertension (p=0.002) and diabetes mellitus (p=0.001). GRACE scores and maximum troponin values were significantly higher in hyponatremic patients (p= 0.001 and 0.05, respectively). There was no significant difference in prior heart failure or home diuretic use between the two groups. Overall 1-year mortality was 4.58% and 30-day all-cause readmission rate was 13.46%. For patients with hyponatremia on admission, unadjusted odds of 30-day readmission were 36% higher (Odds Ratio 1.36, 95% CI 1.00 to 1.85) and 1-year mortality odds were almost 3-fold higher (Odds Ratio 2.79, 95% CI 1.71 to 4.55). Conclusions: Hyponatremia was associated with higher early readmission and lower 1-year survival. Serum sodium levels may represent a cost-effective biomarker of adverse post-discharge outcomes. The potential incremental prognostic information of serum sodium when added to existing readmission and post-discharge mortality risk prediction instruments should be investigated.