Plain-English summary
Kidney disease is one of the most common serious conditions in older cats, and its early signs are notoriously easy to miss. A 2021 study looked at an unglamorous but genuinely observable place: the litter box.
Owners of cats with chronic kidney disease, and owners of cats they considered healthy, were asked to clean the box daily for a week and record what they found. Cats with kidney disease passed stools measurably less often. Among cats with the disease, 42% went less than once a day; among apparently healthy cats, 15% did.
The stool's consistency did not tell the two groups apart. Only the frequency did — and frequency is precisely the thing that goes unrecorded unless someone decides to count.
What the study found
Owners first completed an online questionnaire about their cat's health and litter box habits, including what they expected their cat's frequency and fecal scores to be. They were then asked to clean the box daily for seven days and report what they actually observed each day.
The analysis included 124 owners of apparently healthy cats and 43 owners of cats with chronic kidney disease who submitted two or more days of daily observations in addition to the questionnaire.
Eighty-five percent of the apparently healthy cats were observed to defecate one or more times per day; 15% went less than once per day. Among the cats with chronic kidney disease, 58% went one or more times per day and 42% went less than once per day. The difference in the proportion going less than once daily was significant at P <0.0001, and observed frequency overall was significantly lower in the kidney disease group at P = 0.02.
Observed fecal scores — the consistency measure — were not significantly different between the two groups.
The authors' conclusion was deliberately measured: the observed bowel movement frequency of cats with chronic kidney disease was lower than that of apparently healthy cats, and this represents a clinically important variation from normal.
What this study cannot tell you
This is a small, self-selected survey, and it should be read as one.
The kidney disease group numbered 43 cats. The comparison group was "apparently healthy" as judged by their owners, not confirmed by veterinary examination — so some of those cats may have had undetected conditions of their own. All the data was collected by owners at home, without independent verification, and while the protocol asked for seven days, cats were included with as few as two.
Most importantly, the direction of this study runs backwards from the question owners actually care about. It compared cats already diagnosed with kidney disease against others. It did not follow undiagnosed cats to see whether a change in litter box frequency arrives before a diagnosis does. Nothing here establishes that watching the litter box detects kidney disease early — only that, once present, the disease is associated with a different pattern.
And the overlap is substantial. Nearly six in ten cats with kidney disease still went at least once a day, and roughly one in seven healthy cats did not. This is a difference between groups, not a test that sorts individual cats.
What pet owners should track
If you are going to track this, track it in a way that produces a usable record:
- How many stools you find each day, noted on the day — not reconstructed at the end of the week
- Whether that number has changed from your cat's own usual pattern, which matters far more than any general rule
- How long the change has been going on
- In a multi-cat home, note that you cannot attribute stools to a specific cat from a shared box — say so in the record rather than guessing
- Bring it up at a routine visit if the change persists; contact your veterinarian sooner if your cat is straining, vomiting, off food, or seems uncomfortable
Your cat's own baseline is the reference point. A cat that has always gone once every other day is telling you something different than a cat that used to go twice a day and now goes once every other day.
What PAWai can help organize
This is the kind of observation that survives well in a record and badly in memory. PAWai can hold a simple dated count alongside the rest of your cat's history, so a gradual change reads as a trend instead of a vague sense that something is different. PAWai does not screen for kidney disease, does not interpret litter box patterns, and does not tell you whether a change is significant. Chronic kidney disease is diagnosed by a veterinarian using clinical examination and laboratory testing — never by counting at home. PAWai's role is to make sure what you noticed is still there, with its dates, when your vet asks.
Disclaimer
PAWai organizes information and educates pet owners. PAWai does not diagnose conditions or recommend treatment. Always consult a licensed veterinarian for medical decisions about your pet.
Citation
Jones, S. E., Quimby, J. M., Summers, S. C., Adams, S. M., Caney, S. M. A., & Rudinsky, A. J. (2021). Survey of defecation habits in apparently healthy and chronic kidney disease cats. Journal of Feline Medicine and Surgery, 24(2), 131–141. https://doi.org/10.1177/1098612X211012684