Can treatment response to SGLT2-inhibitors in syndrome of inappropriate antidiuresis be predicted by copeptin, natriuretic peptides and inflammatory markers?

Abstract

Purpose The syndrome of inappropriate antidiuresis (SIAD) is the main cause of hyponatremia and the SGLT2-inhibitor empagliflozin is a promising new treatment option. A biomarker predicting treatment response could optimize treatment success. Materials and methods Secondary analysis of a trial including 84 hospitalized patients with SIAD-induced hyponatremia. Patients were randomized to four days of treatment with empagliflozin 25 mg/d (n = 43) or placebo (n = 41) with both groups receiving fluid restriction <1000 ml/d. Baseline levels of copeptin, the natriuretic peptides MR-proANP and NT-proBNP and C-reactive protein (CRP) were evaluated as predictors for treatment response defined as absolute sodium change, using linear regression models. Additionally, urinary sodium was assessed as predictor for non-response to fluid restriction alone by constructing the receiver-operating characteristic (ROC) curve. Results No clinically relevant predictive value for treatment response to empagliflozin could be found for copeptin, MR-proANP, NT-proBNP or CRP. A urinary sodium cut-off of >76 mmol/l led to a specificity of 91.7% [95% confidence interval (CI): 75%, 100%] and sensitivity of 51.9% [33.3%, 70.4%] to predict non-response to fluid restriction alone. Conclusions Based on our data, no biomarker could be identified as predictor for treatment response to empagliflozin. Urinary sodium was confirmed as a good marker for non-response to fluid restriction in SIAD patients. Clinical trial registration: ClinicalTrials.gov (Number: NCT02874807)