ABSTRACT
BACKGROUND: This article aims to reveal misconceptions about methods of assessment of hydration status and impact of the water disorders on the progression of kidney disease or renal dysfunction. MATERIALS AND METHODS: The PubMed database was searched for reviews, meta-analyses and original articles on hydration, volume depletion, fluid overload and diagnostic methods of hydration status, which were published in English. RESULTS: Based on the results of available literature the relationship between the amount of fluid consumed, and the rate of progression of chronic kidney disease, autosomal dominant polycystic kidney disease, and kidney stones disease was discussed. Selected aspects of the assessment of the hydration level in clinical practice based on physical examination, laboratory tests, and imaging are presented. The subject of in-hospital fluid therapy is discussed. Based on available randomized studies, an attempt was made to assess, which fluids should be selected for intravenous treatment. CONCLUSIONS: There is some evidence for the beneficial effect of increased water intake in preventing recurrent cystitis and kidney stones, but there are still no convincing data for chronic kidney disease and autosomal dominant polycystic kidney disease. Further studies are needed to clarify the aforementioned issues and establish a reliable way to assess the volemia and perform suitable fluid therapy.