Hyponatremia as a Predictor of Complicated Appendicitis.

Background Acute appendicitis is one of the most common surgical emergencies, presenting as either uncomplicated or complicated disease. Complicated cases, characterized by perforation, abscess, or inflammatory mass, are associated with poorer outcomes and require timely identification to guide optimal management. Although several international studies have suggested that serum hyponatremia may predict complicated appendicitis, data from Middle Eastern populations remain limited. Method A quantitative, retrospective cohort study was conducted at Buraidah Central Hospital, Qassim Region, Saudi Arabia, to evaluate hyponatremia as a predictor of complicated acute appendicitis. Medical records of 965 patients diagnosed between January 2020 and December 2023 were reviewed using a census sampling design. Patients aged 14 years and above with complete records were included, while those with uncomplicated appendicitis, missing data, or comorbidities affecting sodium balance were excluded. Data on demographic, laboratory, and clinical variables were analyzed using Python. Inverse probability of treatment weighting was applied to minimize confounding, and statistical significance was set at p < 0.05. Results The overall prevalence of hyponatremia in the study population was 11.3%, and that among patients with complicated appendicitis was 4%. Hyponatremia occurred in 6.5% of pediatric and 11.8% of adult patients. In the gender-stratified model, age (adjusted OR [AdjOR] = 1.027; 95% CI: 1.001-1.053) and serum sodium (AdjOR = 1.207; 95% CI: 1.053-1.383) showed significant positive associations with complicated appendicitis. Similarly, in the model stratified by surgical procedure, age (AdjOR = 1.029; 95% CI: 1.004-1.055) and serum sodium (AdjOR = 1.168; 95% CI: 1.024-1.333) remained significant predictors. Contrary to the initial hypothesis and existing literature, higher serum sodium levels, rather than hyponatremia, were associated with an increased likelihood of complicated appendicitis. Conclusion This study highlights a paradoxical positive association between serum sodium levels and complicated appendicitis, differing from prior evidence that linked hyponatremia to severe disease. While serum sodium alone is not a reliable standalone predictor, its diagnostic value is enhanced when interpreted alongside other clinical and laboratory parameters. The combined assessment of sodium levels and patient age may improve early risk stratification and guide timely clinical decision-making.