The study aims to verify the sensitivity and specificity of a tool to assess the state of hydration of the older person to identify those at risk of dehydration.

Dehydration is the result of insufficient fluid intake and can be consequent to an alteration of thirst mechanisms or fluid loss from the intestinal and respiratory tracts. The use of diuretics can lead to dehydration too. The risk of dehydration induced by acute or chronical diseases is increased in older people because of the reduced capacity to maintain a proper fluid balance. Lower muscle mass, reduced kidney function, physical and cognitive disabilities, blunted thirst, and polytherapy are recognized as main factors for dehydration risk in older people.For these reasons, coordinated efforts are necessary to develop comprehensive assessment tool to monitor hydration in hospitalised older adults. We need to develop a pathway of screening to detect early stage dehydration in older patients in order to correct it precociously. Presently, no standardized clinical dehydration assessment method exists and there are relatively few papers investigating hydration status. A new tool was created: the Geriatric Dehydration Screening Tool - Modified doesn't require laboratory parameters, and thus its use is feasible outside hospital settings. The aim of this study is to evaluate the diagnostic accuracy of the Geriatric Dehydration Screening Tool - Modified in the assessment of the hydration status of hospitalized older population.

Inclusion Criteria:

• Complete blood tests: Urea, Glucose, Sodium, Potassium reported not more than 24 hours before the observation;
• Absence of known cognitive impairments (Mini-Mental State Examination > 24).

Exclusion Criteria:

• Age < 65;
• Mini-Mental State Examination < 24.

The study will concern people aged 65 or over, admitted to the medical departments of the Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico. Critical, pediatric and psychiatric areas are excluded.