Frequent Urination

• In addition to a sweet smell in the urine, if you notice your cat frequently urinating or urinating outside the litter box, this might be a sign of kidney disease.
  
  

Diabetes

• Diabetic cats will often produce a sweet odor in the urine, caused by excessive glucose passing through the system.
  
  

Acetonemia

• Acetonemia is a condition in which there are large amounts of acetone bodies in the blood, and can sometimes be detected by a strong, sweet smell in the urine. This can be caused by the kidneys failing to do their job properly.
  
  

Increased Thirst

• If you find that your cat is drinking more than usual, this could indicate kidney disease, including diabetes. There might not be an excessive odor, however.
  
  

Medical Attention

• If you suspect kidney disease, you should schedule a complete physical with your veterinarian as soon as possible, regardless of whether or not you smell a sweetish odor in the urine.
  
  

Long-term Prospects

• If your cat has kidney disease or even diabetes, the long-term prospects are good for it living a long life. Many forms of kidney disease can be controlled---and in some cases eliminated---with the right regimen of diet and medication, including insulin.