Dear Christopher Cat: Gertie, my 12-year-old cat, was recently diagnosed with chronic kidney disease. I’m uncertain how to proceed, because I’m getting conflicting treatment recommendations from the two veterinarians I consulted. What now?

Christopher Responds: Chronic kidney disease (CKD), the most common kidney problem in cats, is also called chronic renal insufficiency and chronic renal failure. The disease becomes more prevalent as cats age, striking one in three senior cats.

The goals of treatment are to identify and address the cause of the cat’s CKD, minimize its unpleasant effects, and slow the progression of the disease.

Treatment is guided by the disease’s severity, measured in stages defined by the International Renal Interest Society (IRIS).

To determine Gertie’s IRIS stage, her veterinarians consider the level of creatinine in her blood. Creatinine, a byproduct of muscle metabolism, is excreted by the kidneys, which filter the blood and remove waste materials.

As kidney function wanes, creatinine builds up in the blood. Higher creatinine levels mean a higher IRIS stage.

The IRIS stage also takes into account any protein in Gertie’s urine and her blood pressure.

Ask your veterinarians for Gertie’s IRIS stage (1, 2, 3 or 4), and then learn about treatment recommendations at the IRIS website, www.iris-kidney.com. You’ll find information on fluid therapy, diet, omega-3 fatty acid supplementation and medications.

Remember, though, that the IRIS guidelines are suggestions, not rules, and that patients are always treated as individuals. Some treatment recommendations remain controversial, even within IRIS, so it’s not surprising that your veterinarians’ opinions about how to treat Gertie may differ.