Association of serum osmolality levels with all-cause mortality risk in patients with DKA

Background The purpose of this study was to investigate the relationship between serum osmolality levels and 28-day mortality in patients with DKA. Method Data for this observational cohort study were obtained from the MIMIC-IV3.0 database. The participants were divided into five groups based on the serum osmolality quintiles. The primary outcome was 28-day mortality. We employed Cox proportional hazards regression analysis and threshold effect analysis to assess the relationship between serum osmolality levels and 28-day mortality in patients with DKA. Results The study included 1026 patients; the mean age was 52 years, 55.0% were male. Our findings indicate that serum osmolality is associated with an increased risk of 28-day mortality, exhibiting a U-shaped relationship. Altered serum osmolality levels, whether lower or higher, are linked to a heightened risk of mortality. When osmolality < 308.9 mmol/L, the 28-day mortality risk decreased by 5.4% (HR 0.946, 95% CI 0.938–0.959) for every 1 mmol/L increase. At osmolality ≥ 308.9 mmol/L, there was a 3.5% (HR 1.035, 95% CI 1.030–1.039) increase in the 28-day mortality risk for every 1 mmol/L increase in osmolality. The risk of mortality was lower at osmolarity of 297–314 mmol/L. Conclusion A U-shaped correlation between initial serum osmolality and 28-days all-cause mortality in patients with DKA was identified. These results underscore serum osmolality’s critical role in early mortality among patients with DKA.