Correlation study between serum osmolality and all-cause mortality in intensive care unit patients with heart failure

LIANG Panpan; CHEN Yu; LIU Renhuai; LI Heyun; ZHANG Meng; SU Binxiao

doi:10.13276/j.issn.2097-1656.2026.03.019

Abstract：Objective To investigate the association between serum osmolality(SOSM)and all-cause mortality in patients with heart failure(HF)in the intensive care unit(ICU),providing a reliable theoretical basis for the early risk stratification and individualized treatment strategies of critically ill patients.Methods A retrospective cohort study design was adopted based on the data from the Medical Information Mart for Intensive Care-Ⅳ database.Patients were divided into three groups(high-level group,medium-level group,and low-level group)based on the tertiles of SOSM levels.Thirty-day all-cause mortality served as the primary outcome,with secondary outcomes measured at 90 d and one year.Survival probabilities across groups were estimated via Kaplan-Meier analysis.Additionally,the relationship between SOSM and all-cause mortality in patients with HF was explored by using multivariate Cox proportional hazards regression,restricted cubic spline(RCS),and subgroup analyses based on variables such as age and gender.Results A total of 15 431 HF patients were included,with a median age of 74 years,among whom 8 654 were male(56％).Kaplan-Meier survival analysis showed that the survival rate of the high-level group was significantly lower than that of the other groups(log-rank P＜0.000 1).Cox proportional hazards model analysis showed a significant increase in 30 d mortality risk in the high-level group[HR(95％CI)=1.77(1.60,1.96),P＜0.001]and the low-level group[HR(95％CI)=1.41(1.27,1.57),P＜0.001]compared to the medium-level group.RCS analysis showed a distinct U-shaped relationship between SOSM and all-cause mortality,with an inflection point of 30 d mortality at 281.87 mOsm/L.Conclusion Among critically ill HF patients,high SOSM is significantly associated with an increased risk of all-cause mortality at 30 d,90 d,and 1 year.SOSM can be adopted to assess the severity of HF patients in the ICU and to provide effective indicators for guiding treatment.