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Abstract: PO1142

Trends of Overall Mortality by Severity of Hyponatremia: Five-Year Mortality Rates

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

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

Authors

  • Umukoro, Peter Eloho, Indiana University School of Medicine, Indianapolis, Indiana, United States
  • Lodhi, Fahad Aftab khan, Marshfield Clinic Health System, Marshfield, Wisconsin, United States
  • Najjar Mojarrab, Javad, Marshfield Clinic Health System, Marshfield, Wisconsin, United States
Background

We have previously reported increasing strengths of association between degree of hyponatremia on hospital admission and proportions of overall mortality at 1 year post-hospitalization. It is unclear if this association persists in the long term and if this association with overall mortality occurs in a linear manner. Here, we further explore this association over a longer mean follow up period. We hypothesized that a dose response relationship occurs between varying degrees of hyponatremia and overall mortality.

Methods

We obtained data from 46,783 patients, average age 62.2 years, 51.3% males, admitted from January 1, 2012 to December 31, 2016 at a tertiary referral hospital in Central Wisconsin. Of these, 7468 patients had admitting serum sodium <135 and 39315 controls with normal serum sodium (135-145). We parsed hyponatremia based on their admitting serum sodium as mild (130-134), moderate (125-129) and profound (<125) degrees of hyponatremia and compared them with controls. We obtained their vital status (alive or deceased) up to December 31, 2018 over a mean follow up period of 4.7 years. We used Cox proportional hazards model to estimate hazard ratios between varying degrees of hyponatremia compared with normonatremia group after adjusting for covariates.

Results

Hyponatremia occurred in 17.9% of total hospitalizations during the study period. Of 7468 patients with hyponatremia, there were 6,135 (82.2%), 995 (13.3%) and 338 (4.5%) with mild, moderate, and profound degrees of hyponatremia respectively. Hazard ratios for mild, moderate and severe hyponatremia when compared to controls was 1.35 (95% CI: 1.28 – 1.43), 1.81 (95% CI: 1.24 – 2.56) and 2.01 (95% CI: 1.24 – 3.27) respectively (all p<0.001) after adjusting for covariates.

Conclusion

All-cause mortality from CVD, stroke, cancer, liver cirrhosis deaths were occurring to a significant proportion even in patients with milder degrees of hyponatremia with a dose response relationship. Clinicians should incorporate hyponatremia in their assessment of critical patients as this is associated with mortality. These findings need to be explored further with research geared towards elucidating mechanisms that contribute to death in hyponatremia, and if correcting sodium levels early in hospitalizations may prevent mortality in the future.