Adherence to the Sociedad Española de Oncología Médica (SEOM) Algorithm for the Treatment of Hyponatremia in Oncology Patients in Spain: The ALGA Study.

Introduction: The ALGA study explored adherence of Spanish treatment centers to the Sociedad Española de Oncología Médica (SEOM) treatment algorithm for oncology patients with hyponatremia that requires treatment as the main cause of hospitalization, and evaluated the impact of adherence to this algorithm on patient outcomes.

Methods: This retrospective study recruited patients aged at least 18 years with cancer, treated for at least one episode of hyponatremia secondary to the syndrome of inappropriate antidiuretic hormone secretion (SIADH). The primary outcome was the proportion of patients whose treatment adhered to the SEOM algorithm, evaluated using a pre-defined decision tree. Secondary outcomes included length of hospitalization, and time to serum sodium level improvement. Perceived center adherence to the SEOM algorithm was also assessed.

Results: Seventy patients from four treatment centers were included. Twenty (28.6%; 95% confidence interval [CI] 18.0, 39.2) patients on hyponatremia treatment adhered to the SEOM algorithm, with a perceived adherence of 51.0-75.0%. Algorithm adherence in candidates for chemotherapy was 36.4% (n = 8) versus 25.0% (n = 12) for non-candidates for chemotherapy. Median time to serum sodium level improvement in patients managed adherently was 80.5 h (95% CI 38.3, 331.4) versus 134.6 h (33.2, 444.9) in patients managed non-adherently. Median time to hospital discharge was 16.5 days (95% CI 8.0, 27.0) in patients managed adherently versus 9.5 days (7.0, 22.0) in patients managed non-adherently.

Conclusion: In Spanish centers, the SEOM algorithm was adhered to in less than one-third of patients, in contrast to higher levels of perceived adherence. This requires further investigation; however, algorithm use could require further clarification, especially in non-candidates for chemotherapy.