Value of hyponatremia in predicting disease severity of patients with acute pancreatitis

Objective To investigate the value of hyponatremia in predicting the severity of acute pancreatitis( AP). Methods Clinical data were collected from 459 AP patients who attended The Affiliated Hospital of Southwest Medical University from January to December2019,and according to the serum Na+level at the time of onset,the patients were divided into hyponatremia group with 123 patients and non-hypernatremia group with 336 patients. The two groups were analyzed and compared in terms of baseline data,complications,mortality rate,and AP-related scores. The t-test or the Mann-Whitney U test was used for comparison of continuous data between two groups,and the chi-square test or the Fisher's exact test was used for comparison of categorical data between two groups. The multivariate logistic regression analysis was used to identify the influencing factors for moderate-to-severe AP( M-SAP),acute necrotic collection( ANC),and systemic inflammatory response syndrome( SIRS),and the receiver operating characteristic( ROC) curve was used to evaluate the value of related indices. Results Compared with the non-hyponatremia group,the hyponatremia group had a significantly younger age and significantly higher body mass index and proportion of patients with diabetes,and most patients had hyperlipidemic AP( all P < 0. 05). Compared with the non-hyponatremia group,the hyponatremia group had significantly higher triglyceride,blood glucose,hematocrit,C-reactive protein,procalcitonin,neutrophil-to-lymphocyte ratio,and proportion of patients with CT severity index > 2 on admission( all P<0. 05). Compared with the non-hyponatremia group,the hyponatremia group had a significantly higher proportion of patients with M-SAP or SAP,acute peripancreatic fluid accumulation,ANC,SIRS,acute respiratory distress syndrome,and multiple organ failure( all P <0. 05). The multivariate logistic regression analysis showed that hyponatremia( odds ratio [OR]= 5. 272,95% confidence interval [CI]:2. 771-10. 029,P < 0. 001),age( OR = 0. 976,95% CI: 0. 956-0. 995,P = 0. 011),Ranson score >2( OR = 10. 437,95% CI:4. 116-26. 465,P < 0. 001,and alcoholic AP( OR = 3. 249,95% CI: 1. 214-8. 694,P = 0. 019) were independent risk factors for M-SAP,and the combination of these four indices had an area under the ROC curve( AUC) of 0. 759; hyponatremia( OR = 1. 931,95% CI:1. 007-3. 700,P = 0. 047; OR = 3. 792,95% CI: 2. 193-6. 556,P < 0. 001) and Ranson score > 2( OR = 2. 621,95% CI: 1. 304-5. 271,P = 0. 007; OR = 5. 845,95% CI: 3. 066-11. 143,P < 0. 001) were independent risk factors for ANC and SIRS,and the combination of these two indices had AUCs of 0. 677 and 0. 742,respectively,in predicting ANC and SIRS. Conclusion Hyponatremia can be used as a simple reference index for evaluating disease severity in patients with AP.