Rudinsky AJ, Morrison JA, Parker VJ, et al. Poorly concentrated urine is associated with an increased risk of developing chronic kidney disease in apparently healthy cats. J Am Vet Med Assoc. Published online August 26, 2026. doi:10.2460/javma.26.05.0335.
Chronic kidney disease (CKD) is one of the most common health problems affecting older cats. One of the challenges is that kidney disease can develop gradually, and cats may appear healthy even while changes are beginning to occur. A recent study suggests that a routine urine test may provide an important clue that a cat could be at increased risk of developing CKD.
Researchers examined whether a cat’s ability to concentrate its urine could help identify cats more likely to develop kidney disease in the future. The study focused on urine specific gravity (USG), a measurement commonly included in a urinalysis that indicates urine concentration or dilution.
The researchers reviewed the medical records of more than 15,000 apparently healthy cats for possible inclusion in a two-year retrospective study. Cats were divided by age and according to whether their urine specific gravity was below 1.035 or at least 1.035. The researchers then looked at which cats went on to receive a presumptive diagnosis of chronic kidney disease during the following two years.
The results were particularly significant for mature cats between 11 and 15 years of age. Cats in this age group whose initial urine specific gravity was below 1.035 had approximately three times the odds of being diagnosed with CKD during the study period compared with cats whose urine was more concentrated. They also tended to be diagnosed with CKD sooner.
Healthy kidneys conserve water by concentrating urine. As kidney function changes, the kidneys may gradually lose some of this ability. Importantly, changes in urine concentration may become apparent before a cat has obvious signs of illness.
The findings suggest that poorly concentrated urine in an otherwise healthy mature cat shouldn’t necessarily be dismissed simply because other signs of kidney disease aren’t present. Instead, it may be a reason for veterinarians to look more closely at kidney health and consider more individualized monitoring or additional testing.
This does not mean that a urine specific gravity below 1.035 proves that a cat has CKD or will inevitably develop it. Urine concentration can be influenced by many factors, and CKD cannot be diagnosed from a single USG measurement alone. The study was also retrospective, meaning researchers examined existing medical records rather than following cats prospectively under controlled study conditions. The CKD diagnoses were therefore presumptive rather than uniformly confirmed using a standardized diagnostic protocol.
What the study does provide is another piece of evidence supporting the value of routine health screening for aging cats, even when they seem perfectly healthy. A relatively simple test such as urinalysis may reveal subtle changes that warrant closer attention.
For cat owners, the message is simple: regular veterinary examinations and routine laboratory testing become increasingly important as cats age. Identifying changes sooner may give veterinarians an opportunity to monitor kidney health more closely and recognize CKD earlier, when cats may still look and act completely normal.
One of the greatest challenges with chronic kidney disease is that it can progress quietly. By the time a cat shows obvious signs of illness, significant changes in kidney function may already have occurred.
This study is important because it suggests that information already available through a simple, routine urinalysis could help veterinarians recognize cats that may be at greater risk for developing CKD, while those cats still appear healthy.
Identifying at-risk cats earlier could lead to closer monitoring and additional testing, giving veterinarians a better opportunity to recognize kidney disease sooner. Just as importantly, findings like these can help researchers determine which cats should be studied more closely as they search for better ways to predict, detect, and ultimately intervene in CKD.