<qa>  What is the main objective of the study?Our main objective is to evaluate the effect of stimulated and calculated water intake per kg of patient weight on the state of hydration and renal function in a population of elderly individuals. It is also within the scope of this project to evaluate the presence of chronic dehydration in elderly patients as well as in a subgroup of diabetic patients, and to compare different methods of evaluation of renal function. Design: Clinical trial Randomized for the main objective and cross-sectional study for secondary objectives. 