The prevalence and outcomes of syndrome of inappropriate antidiuretic hormone secretion (SIADH) among patients hospitalized with lung cancer: Insights from the Nationwide Inpatient Sample.

e20103 Background: Syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common complication in cancer patients, contributing to substantial morbidity. Lung cancer patients, especially those with small cell lung cancer (SCLC), face a higher risk of developing SIADH due to factors such as ectopic antidiuretic hormone (ADH) production, brain metastases, and chemotherapy-induced secretion. Despite its clinical relevance, the influence of SIADH on hospitalization outcomes in lung cancer patients remains underexplored. This study seeks to examine the impact of SIADH on inpatient outcomes in this population, addressing a critical gap in the existing literature. Methods: The 2019 National Inpatient Sample was utilized to identify patients diagnosed with lung cancer using International Classification of Diseases, 10th Revision (ICD-10) codes. The cohort was stratified into two groups: patients admitted with a diagnosis of SIADH and those without. Sociodemographic variables and comorbidities were systematically compared between the two groups. The primary outcome of interest was all-cause in-hospital mortality, with additional secondary outcomes analyzed. Multivariate regression models were employed to assess disparities in outcomes between the groups, with statistical significance set at p < 0.05. Results: Among 317,180 adult patients hospitalized with lung cancer in 2019, 2,605 (0.8%) were admitted with a diagnosis of SIADH. These patients were significantly younger, with a mean age of 67.9 years compared to 69.6 years for those without SIADH ( p < 0.005), and had a higher proportion of females (55.5%) compared to males (44.5%).Lung cancer patients admitted with SIADH demonstrated significantly lower odds of all-cause mortality (adjusted odds ratio [aOR], 0.31; 95% confidence interval [CI], 0.18–0.54; p < 0.005), concurrent pulmonary embolism (aOR, 0.12; 95% CI, 0.03–0.49; p = 0.003), acute kidney injury (aOR, 0.58; 95% CI, 0.42–0.78; p < 0.001), and septic shock (aOR, 0.13; 95% CI, 0.04–0.41; p < 0.001).Additionally, patients with SIADH experienced shorter hospital stays (mean length of stay: 5.1 days vs. 6.3 days; p < 0.005) and incurred lower hospitalization costs ($47,429 vs. $69,449; p < 0.001). Conclusions: Lung cancer patients with concurrent SIADH had significantly lower odds of mortality, acute kidney injury, pulmonary embolism, and septic shock, along with shorter hospital stays and reduced hospitalization costs compared to those without SIADH. These findings may offer valuable insights into the prognosis of lung cancer patients with SIADH compared to those without this condition.