Thanks @nadhiljanitra!

While ants surrounding your urine is a possible indicator you have diabetes, it also could mean that you ingested high amounts of sugar, and it's simply being filtered out by the kidneys. Doctors used to taste urine to determine sugar content, but nowadays it's a lot easier with blood tests. I would say that it's probably a good idea to get tested if you find ants attracted to your toilet however. Better safe than sorry!