Copeptin in autosomal dominant polycystic kidney disease: real-world experiences from a large prospective cohort study

Abstract

Background The identification of new biomarkers in autosomal-dominant polycystic kidney disease (ADPKD) is crucial to improve and simplify prognostic assessment as a basis for patient selection for targeted therapies. Post-Hoc-Analyses of the TEMPO 3:4 study indicated that copeptin could be one of those biomarkers. Methods Copeptin was tested in serum samples from patients of the AD(H)PKD study. Serum copeptin levels were measured using a time-resolved amplified cryptate emission (TRACE) based assay. In total, we collected 711 values from 389 patients without tolvaptan treatment and a total of 243 values (of which 64 were pre-tolvaptan) from 94 patients on tolvaptan. These were associated to rapid progression and disease-causing gene variants and their predictive capacity tested and compared to the Mayo Classification. Results As expected, copeptin levels showed a significant negative correlation with eGFR. Measurements on tolvaptan showed significantly higher copeptin levels (9.871 pmol/l vs. 23.90 pmol/l at 90/30 mg; p < 0.0001) in all CKD stages. Linear regression models (n = 133) show that copeptin is an independent predictor of eGFR slope. A clinical model (including eGFR, age, gender, copeptin) was nearly as good (R2 0.1196) as our optimal model (including htTKV, eGFR, copeptin, R2 0.1256). Adding copeptin to the Mayo model improved future eGFR estimation. Conclusion Copeptin levels are associated with kidney function and independently explained future eGFR slopes. As expected, treatment with tolvaptan strongly increases copeptin levels.