RESULTS: Fifty-four LC patients were identified; 19% small-cell, 68% stage 4, 63% male, mean age 63 years. Most patients experienced moderate (87%) vs. severe (13%) hyponatremia; 46% were symptomatic. The most common symptoms were fatigue, confusion, headache, muscle weakness and nausea/vomiting. Mean (SD) duration of moderate/severe hyponatremia was 19 (36.0) days with the majority of hyponatremia untreated (72% moderate, 57% severe). The most common active therapies were fluid restriction and furosemide. Treated patients were significantly (p=.03) more likely to have Na+>130 at 72 hours. Thirty-seven percent of patients experienced another episode of moderate/severe hyponatremia. In the 30 days prior to index, 52% were hospitalized, 39% (24%) received chemotherapy (radiation), 19% were designated a fall risk and 9% experienced a fall. In the 30 days post index, 26% of patients were hospitalized, 44% (28%) received chemotherapy (radiation), 26% received comfort care, 32% were designated a fall risk and 4% experienced a fall. A total of 40 (74%) patients died. Median (95% CI) survival time was 95 (53-165) days; 15% died in the first 30 days.