As our cats age, their bodies stop working as well as they used to. Just like with us. I'm sure most of us have noticed our grandparents needing more care as they age. Our senior cat needs to be watched more closely for signs of body functions not working as well as they could.
Kidney disease is something your older cat is at risk of. Sometimes it is because of changes in the kidney, and sometimes it can be due to other organs in the body not functioning properly. If the heart is not working