Impact of natremia on metastatic non small cell lung cancer patients receiving immune checkpoint inhibitors

Hyponatremia has been established as a prognostic indicator of survival in metastatic non-small cell lung cancer (mNSCLC). Conversely, the influence of normal sodium levels remains unexplored. This study aims to investigate the impact of natremia in mNSCLC patients undergoing treatment with immune checkpoint inhibitors (ICIs). Clinical and biochemical data of patients treated with ICIs for mNSCLC were obtained. Availability of baseline sodium values was a study inclusion criterion. Patients were categorized into two groups based on the cut off sodium value, determined using the receiver operating characteristic curve. Subsequently, the influence of sodium levels on response rate (RR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) was analyzed. PFS and OS were assessed via the Kaplan–Meier method. Univariate and multivariate Cox regression analyses were conducted to evaluate prognostic factors for PFS and OS. The analysis included 88 patients, of whom 73.1% were men, with a median age of 71 years (range, 47–91). A comparison between patients with baseline natremia ≥ 140 mEq/L ( n = 43) and those with