What distinguishes diabetes insipidus from diabetes mellitus?

Diabetes insipidus is characterized by increased urine output due to the body's inability to concentrate urine, which is primarily caused by insufficient levels of anti-diuretic hormone (ADH) or a poor kidney response to this hormone. In this condition, despite producing a high volume of urine, there is no significant presence of glucose in the urine, distinguishing it from diabetes mellitus, where the high urine output is often accompanied by glucosuria (glucose in the urine) due to elevated blood sugar levels.

The correct answer highlights that the key feature of diabetes insipidus is increased urine production without the presence of glucose, which is essential in differentiating the two conditions. This distinction is crucial in clinical practice to provide the appropriate management and treatment for each type of diabetes.