5th International Conference on Cardiovascular Medicine & Heart Failure · 2026-05-15 · Cardiology

Clinical and Diagnostic Value of Copeptin as a Biomarker in Patients with Diabetes Insipidus

Nazirova Gavhar Ilg'or qizi¹, Negmatova Gulzoda Shuhratovna²
Second-year Master’s Resident, Department of Endocrinology, Samarkand State Medical University, Samarkand, Uzbekistan¹, PhD, Associate Professor, Department of Endocrinology, Samarkand State Medical University, Samarkand, Uzbekistan²,

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Abstract

Diabetes insipidus is a disorder characterized by impaired water balance resulting from deficiency of arginine vasopressin secretion or renal resistance to its action. Differential diagnosis between central diabetes insipidus, nephrogenic diabetes insipidus, and primary polydipsia remains a significant clinical challenge because of overlapping symptoms and limitations of conventional diagnostic methods. Copeptin, a stable peptide derived from the precursor of arginine vasopressin, has recently emerged as a promising biomarker for the diagnosis and management of diabetes insipidus. This study evaluated the clinical and diagnostic significance of copeptin levels in patients with various forms of diabetes insipidus. The results demonstrated that copeptin measurement significantly improves diagnostic accuracy and facilitates differentiation between different disorders of water metabolism.

Keywords: copeptin, diabetes insipidus, arginine vasopressin, biomarkers, water balance disorders, central diabetes insipidus, nephrogenic diabetes insipidus

Diabetes insipidus is characterized by excessive polyuria and polydipsia caused by impaired regulation of water homeostasis. Conventional diagnostic approaches, including the water deprivation test, are time-consuming, uncomfortable for patients, and sometimes inconclusive. Accurate differentiation between central diabetes insipidus, nephrogenic diabetes insipidus, and primary polydipsia is essential because therapeutic strategies vary considerably. Arginine vasopressin itself is unstable in plasma and difficult to measure reliably. Copeptin, which is secreted in equimolar amounts with vasopressin, provides a more stable and easily measurable biomarker reflecting endogenous vasopressin secretion. Recent studies suggest that copeptin may improve diagnostic precision and reduce the need for prolonged traditional testing procedures.

The aim of the study was to assess the clinical and diagnostic value of copeptin as a biomarker in patients with diabetes insipidus and to determine its effectiveness in differentiating central diabetes insipidus, nephrogenic diabetes insipidus, and primary polydipsia.

The study included 75 patients presenting with polyuria-polydipsia syndrome and 25 healthy individuals as a control group. Patients underwent comprehensive clinical evaluation, serum and urine osmolality testing, water deprivation testing, and copeptin measurement using immunoassay techniques. Magnetic resonance imaging of the hypothalamic-pituitary region was performed in selected patients with suspected central pathology. Based on clinical and laboratory findings, patients were categorized into central diabetes insipidus, nephrogenic diabetes insipidus, and primary polydipsia groups. Statistical analysis was used to compare copeptin levels among different groups and evaluate diagnostic sensitivity and specificity.

Patients with central diabetes insipidus demonstrated significantly lower copeptin levels compared to patients with nephrogenic diabetes insipidus and primary polydipsia (p<0.001). In nephrogenic diabetes insipidus, copeptin concentrations were markedly elevated due to preserved vasopressin secretion with renal resistance. Copeptin measurement showed high diagnostic sensitivity and specificity for differentiating various forms of polyuria-polydipsia syndrome. Stimulated copeptin testing after osmotic stimulation further improved diagnostic accuracy and reduced the frequency of inconclusive results compared to traditional water deprivation testing alone. In several patients, copeptin-based assessment enabled earlier diagnosis and more rapid initiation of targeted therapy.

Copeptin is a highly valuable biomarker for the diagnosis and differential assessment of diabetes insipidus. Measurement of copeptin levels significantly improves diagnostic precision, simplifies evaluation of polyuria-polydipsia syndromes, and facilitates differentiation between central diabetes insipidus, nephrogenic diabetes insipidus, and primary polydipsia. Incorporation of copeptin testing into routine endocrinological practice may optimize diagnostic algorithms, reduce patient discomfort, and contribute to earlier and more effective treatment strategies.

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