Association of Severity of Hyponatraemia with SOFA and APACHE II Scores in Critically Ill Diabetics: A Cross-sectional Study

1. Resident, Department of Internal Medicine, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India. 2. Professor, Department of Internal Medicine, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India. 3. Professor, Department of Internal Medicine, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India. 4. Assistant Professor, Department of Internal Medicine, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India. 5. Senior Resident, Department of Internal Medicine, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India. 6. Resident, Department of Internal Medicine, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India. 7. Resident, Department of Internal Medicine, Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India.

Abstract

Introduction: Hyponatraemia, the most common dysnatraemia in the critically ill, is an independent predictor of mortality, morbidity and poor clinical outcomes. It poses a significant challenge, as both severe hyponatraemia and its management can have lethal consequences. This holds true in diabetic patients as well, where mechanisms other than hyperglycemia contribute to low serum sodium levels, immune dysregulation, and where HbA1c itself is an independent predictor of all-cause mortality. Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores are well-established scoring systems that predict and stratify mortality in critically ill patients. The severity of hyponatraemia, defined by corrected sodium levels, may predict poor clinical outcomes in critically ill diabetic patients.

Aim: To assess the association between the severity of hyponatraemia on admission and SOFA and APACHE II scores in critically ill diabetic patients within the first 24 hours of admission.

Materials and Methods: This cross-sectional study was conducted at Dr. D. Y. Patil Medical College, Hospital and Research Centre, Pimpri, Pune, Maharashtra, India from March 2023 to February 2025 with a sample size of 100 using purposive sampling. All critically ill patients admitted to the intensive care units with a history of diabetes mellitus (any type) were assessed for hyponatraemia (Na+ <135 mEq/L) on admission, corrected for hyperglycemia. A detailed history, physical examination and routine and study-specific investigations were performed. The SOFA and APACHE II scores were calculated from the worst values within the first 24 hours of admission. The data were assessed for normality and correlations were examined between the study parameters.

Results: The mean age of participants was 44.09±11.3 years, with an approximately equal sex distribution; 50% were aged 45-60 years. The mean duration of diabetes was 6.5±5.3 years, predominantly between 1-5 years. Mild, moderate and severe hyponatraemia were observed in 47%, 36%, and 17% of cases, respectively, with mean SOFA and APACHE II scores of 4.77±3.68 and 12.5±8.8. Kruskal-Wallis analysis showed significant differences across hyponatraemia severity for both SOFA and APACHE II scores, with post hoc analyses indicating significant differences for APACHE II across all groups; SOFA scores were significantly higher in moderate and severe hyponatraemia compared with mild hyponatraemia. Corrected sodium levels significantly predicted both disease severity and organ dysfunction severity.

Conclusion: There was a significant rise in the SOFA scores from mild to moderate hyponatraemia, but no significant difference between moderate and severe hyponatraemia patients. APACHE II scores significantly increased across all levels of worsening hyponatraemia severity, indicating the contribution of the extent of hyponatraemia to the overall disease severity but a weaker association with severity of organ dysfunction.

Intensive care units, Mortality, Organ failure, Risk assessment, Syndrome of inappropriate antidiuretic hormone secretion