What happens to a patient with diabetes insipidus in terms of hydration?

In diabetes insipidus, the body is unable to properly regulate water balance due to a deficiency of the hormone vasopressin (also known as antidiuretic hormone, ADH) or a failure of the kidneys to respond to it. This condition leads to the excretion of large volumes of dilute urine. As a result, patients with diabetes insipidus are at a significant risk for dehydration because they lose more water than they take in.

When the kidneys cannot concentrate urine effectively, the excessive loss of water can surpass fluid intake, leading to an imbalance. The symptoms of dehydration may include increased thirst (polydipsia) as the body tries to compensate for the fluid lost. Therefore, the correct answer reflects the physiological response seen in patients with diabetes insipidus, who indeed experience dehydration as a consequence of their condition.