Hello, I’m Dr. Hocheol Shin, or “Dr. Shin.” I study feline kidney health and aging at Greycoat Research.

I earned my Ph.D. studying cancer and immunology, and I’m now building on that experience to explore how we can help cats stay healthier for longer.

In “Reading Papers with Dr. Shin,” we’ll explore research related to feline health together. We’ll look a little deeper into how things work, what the studies actually found, and what those findings might mean for our cats. I’ll explain any unfamiliar terms as we go.

Ready to open today’s paper with Lulu?

Three-Sentence Summary

1. A review of medical records from 569 cats with chronic kidney disease found a pattern of weight loss before diagnosis.
2. Among 273 cats with weights recorded both about a year before diagnosis and at diagnosis, the median change was a loss of approximately 8.9%, but this does not mean kidney disease causes every instance of weight loss.
3. When considering nutritional management at Greycoat Research, recording how much a cat eats and how its body changes over time matters alongside the names of the ingredients it receives.

Introduction: The Date of Diagnosis Is Not Necessarily the Start of the Story

A medical record contains a date when kidney disease was diagnosed. From that point, the condition has a name and a management plan begins. For the cat’s owner, it is an important day, too.

But did the changes inside the body begin on that same day?

The diagnosis date marks when the disease was identified. Understanding what happened before it means going back through the records.

Today’s paper gathered previous weight measurements from cats diagnosed with kidney disease. Rather than stopping at how much they weighed at diagnosis, it examined the path that led to that weight.

Background: The Same 4 kg Can Tell Two Different Stories

Imagine two cats. Both currently weigh 4 kg.

One has stayed around 4 kg for a long time. The other has been steadily losing weight and has now reached 4 kg.

The number is identical. But the second cat raises more questions: when did the loss begin, how much weight was lost, and what happened to food intake and the cat’s condition along the way?

A current weight alone does not reveal that difference. Dated records give the number a direction. That is the central idea for today’s paper: body weight and the way body weight has changed are different kinds of information.

The Study: Gathering Weights Before and After Diagnosis

Freeman and colleagues published this study in the Journal of Veterinary Internal Medicine in 2016.

The researchers collected medical records for 569 cats with chronic kidney disease from six veterinary practices in the United States. They examined weight data spanning up to three years before and after diagnosis. Not every cat had a measurement at every time point.

Among the 273 cats with weights recorded both about a year before diagnosis and at diagnosis, the median percentage change was −8.9%.

When the researchers used the full dataset to estimate the group’s weight trajectory, a declining pattern was apparent from three years before diagnosis. Weight loss also appeared to accelerate after diagnosis.

Reading the Results: Familiar Numbers, Read Together

What interests me is that this question did not require a complicated new test. It required looking differently at weight records that already existed.

At an individual visit, the discussion naturally centers on that day’s number. Put several dates together, and we can distinguish a temporary dip followed by recovery from a stable pattern or a continuing decline.

In this group of cats diagnosed with kidney disease, the decline was visible before the diagnosis. Looking only at records from the diagnosis date onward would miss the earlier part of that pattern.

So the message I take from this paper is not, “Let’s diagnose kidney disease from weight.” It is, “Are we making full use of the records we already have?” The path to a number may raise more useful questions than the number at diagnosis alone.

A Point to Keep in Mind: A Weight Curve Does Not Date the Onset of Disease

The phrase “weight loss began three years before diagnosis” needs particular care. This was a pattern estimated from group data, not a finding that every cat’s kidney disease began three years earlier.

The study also looked backward through the records of cats already diagnosed with kidney disease. That is different from recruiting cats that are losing weight and then following them to see how many develop kidney disease.

Assessments of fat and muscle condition were not consistently available in the records. The study could not separate how much of the lost weight was fat and how much was muscle.

Weight loss alone does not establish kidney disease. It is more appropriate to read these findings as a reason to investigate a change in greater detail, rather than as a replacement for diagnosis.

Personal Thoughts: The Ingredient Is Only Part of the Record

Discussions of nutritional management often focus on ingredient names: what is included and what it is expected to do. Those are useful questions.

But we also need to know how much the cat has been eating and how its weight and overall condition have changed. An explanation of an ingredient cannot, on its own, explain what is happening to the cat receiving it.

That is the direction I would like nutritional management research at Greycoat Research to take. Alongside a record of which ingredients were given, we need records of intake and changes in the cat over time. Connecting a hypothesis about an ingredient with what actually happens to the cat requires both.

An owner’s observations can contribute, too. “My cat seems a little thinner” becomes a more specific conversation when we can discuss when the change started, how large it was, and whether eating patterns changed. These records may help veterinarians make more precise clinical decisions.

The diagnosis date matters. But the cat’s story does not necessarily begin there. This paper encourages us to open the earlier records as well. It did not demonstrate the effect of a particular nutritional ingredient, but it does raise a useful question about what we should be recording.

Next time, we’ll go beyond weight to consider body composition alongside blood test results. Do cats with lower creatinine necessarily have better kidney function?

The findings discussed in this article reflect associations, mechanisms, and early translational evidence rather than confirmed efficacy in cats with kidney disease. Please consult a veterinarian before starting any supplementation protocol.

References

1. Freeman LM, Lachaud M-P, Matthews S, Rhodes L, Zollers B. Evaluation of Weight Loss Over Time in Cats With Chronic Kidney Disease. Journal of Veterinary Internal Medicine. 2016;30:1661–1666.

About the Author

Hocheol Shin, Ph.D. Greycoat Research

B.S./M.S./Ph.D. in Biological Sciences, KAIST (Korea Advanced Institute of Science and Technology)

Research background in cancer immunology, tumor microenvironment, and translational oncology. Currently engaged in companion animal health and longevity research.

Educational Disclaimer

This article is for educational purposes only and is not a substitute for professional veterinary advice, diagnosis, or treatment. It is not intended to diagnose, treat, cure, or prevent any disease.

Please consult your veterinarian before making changes to your cat’s diet, supplements, or care routine.