Objective To explore the correlation between hyponatremia at admission and all-cause mortality within one year after discharge in elderly patients with intestinal obstruction.Methods The 331 cases of elderly patients with intestinal obstruction(aged ≥ 60 years)who visited the General Surgery Department of Nanjing Meishan Hospital from January 2017 to December 2020 were selected as the research objects for retrospective cohort study analysis.According to the patient's blood sodium level at admission,they are divided into two groups:the hyponatremia group(Na＜135 mmol/L)and the non hyponatremia group(Na≥135 mmol/L).Divided into death group and survival group based on whether death occurred within one year after discharge.SPSS 25.0 software was used for statistical analysis.Independent sample t test,x2 test,Kaplan Meier method,and multivariate Cox regression analysis were used to observe the correlation between admission hyponatremia and all-cause mortality within one year after discharge in elderly patients with intestinal obstruction.Results A total of 331 patients were enrolled.The incidence of hyponatremia was 32.3％,and 56 deaths occurred within one year,accounting for 16.92％.The one-year mortality rate in the hyponatremia group was 23.4％(25/107),which was higher than 13.8％(31/224)in the non hyponatremia group.The difference was statistically significant(P＜0.05).The survival analysis(Kaplan Meier)results showed that the survival rate of the hyponatremia group was lower than that of the non hyponatremia group(Log Rank P＜0.05).After adjusting for other confounding factors in multivariate Cox regression analysis,hyponatremia(HR=1.88,95％CI:1.07-3.29)was an independent risk factor for one-year all-cause mortality in elderly patients with intestinal obstruction(P＜0.05).Conclusion Hyponatremia at admission is an independent risk factor for all cause mortality in elderly patients with intestinal obstruction within one year after discharge.