Kidney disease is one of the most common serious health conditions in dogs, particularly those over seven years old. The kidneys filter waste from the blood, regulate fluid balance and electrolytes, and help produce red blood cells. When they lose function — either suddenly or gradually over months to years — the effects range from subtle changes in drinking habits to life-threatening illness. Early detection through routine bloodwork can help give dogs the best chance at slowing progression and maintaining quality of life.
What Is Kidney Disease in Dogs?
The terms kidney disease, kidney failure, and renal failure in dogs are often used interchangeably, but they describe different points on the same spectrum. “Kidney disease” is the broad term for any condition that impairs kidney function. “Kidney failure” or “renal failure” typically refers to more advanced loss of function — when the kidneys can no longer filter waste adequately, and clinical signs appear. Both acute and chronic forms fall under this umbrella.
Kidney disease falls into two categories based on how it develops:
Acute kidney injury (AKI) occurs suddenly, over hours to days. Common causes include toxin ingestion (grapes, raisins, certain medications, antifreeze), bacterial infection, urinary obstruction, or reduced blood flow to the kidneys. AKI is a medical emergency that requires immediate veterinary care. With prompt treatment, some dogs recover fully; others develop ongoing CKD.1
Chronic kidney disease (CKD) develops gradually over months to years and is not reversible. It is significantly more common than AKI in dogs and is most frequently diagnosed in middle-aged to senior dogs. Because the kidneys have substantial reserve capacity, clinical signs of CKD often don’t appear until approximately two-thirds of kidney function has already been lost,1 which is why routine wellness bloodwork can be important for early detection.
Symptoms of Kidney Disease in Dogs
Symptoms vary depending on the stage and type of kidney disease.
Early signs:
Increased thirst (polydipsia)
Increased urination (polyuria) or accidents in house-trained dogs
Occasional nausea or vomiting
Moderate to advanced signs:
Decreased appetite or refusing food
Weight loss
Lethargy and weakness
Bad breath with an ammonia or chemical odor (uremic fetor)
Mouth ulcers or pale gums
Vomiting or diarrhea
Hunched posture or reluctance to move
Severe or end-stage signs:
Inability to stand or significant weakness
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Because early signs mimic many other conditions, a veterinary exam with bloodwork is required to confirm kidney disease. Any dog over seven showing increased thirst and urination should be evaluated — routine senior wellness panels are one of the most reliable ways to catch CKD before symptoms become severe.2
How Is Kidney Disease Diagnosed?
Veterinarians use a combination of tests to diagnose kidney disease and assess severity:2
Serum creatinine: a waste product filtered by the kidneys; elevated levels indicate reduced filtration
SDMA (symmetric dimethylarginine): a newer biomarker that can detect kidney function loss earlier than creatinine alone — studies suggest SDMA may rise when as little as 25% of kidney function is lost, compared to 65–75% for creatinine
BUN (blood urea nitrogen): another waste product; elevated alongside creatinine confirms azotemia
Phosphorus: often elevated in CKD; high levels accelerate kidney damage
Urinalysis: checks urine concentration (specific gravity) and protein levels
Blood pressure: hypertension is a common complication and a staging factor
Renal ultrasound: assesses kidney size, shape, and structure; can identify cysts, stones, or tumors
Stages of Kidney Disease in Dogs
The International Renal Interest Society (IRIS) has developed a widely adopted staging system for CKD in dogs and cats.1 According to IRIS, CKD is staged based on fasting blood creatinine and SDMA concentrations in a stable, hydrated patient after non-renal causes of azotemia have been ruled out.
IRIS Stage | Creatinine (dog) | Clinical Picture |
|---|---|---|
Stage 1 | < 1.4 mg/dL | Non-azotemic; kidney damage present but no elevation in waste products |
Stage 2 | 1.4–2.8 mg/dL | Mild azotemia; subtle or no clinical signs |
Stage 3 | 2.9–5.0 mg/dL | Moderate azotemia; clinical signs typically present |
Stage 4 | > 5.0 mg/dL | Severe azotemia; uremic crisis likely |
Each stage is further characterized by urine protein levels (proteinuria) and blood pressure, which inform treatment priorities. Earlier-stage diagnosis generally means more treatment options and a better prognosis.
Treatment for Kidney Disease in Dogs
According to VCA Animal Hospitals and Today’s Veterinary Practice, treatment for CKD focuses on slowing progression, managing symptoms, and addressing complications — not curing the underlying condition.2,3
Dietary management is a cornerstone of CKD care. Prescription renal diets are formulated with reduced protein, restricted phosphorus, and added omega-3 fatty acids. Phosphorus restriction in particular has been shown to slow the progression of kidney disease. Transitioning gradually and monitoring appetite is important, as some dogs resist diet changes.
Fluid therapy supports kidney function by maintaining hydration and improving blood flow through the kidneys. In earlier stages, encouraging water intake (wet food, water fountains) may be sufficient. In more advanced cases, veterinarians may teach owners to administer subcutaneous fluids at home — a common and manageable part of long-term CKD care.
Medications may include:
Phosphate binders to lower phosphorus absorption
Anti-nausea medications (maropitant, ondansetron) to manage vomiting
Antihypertensive medications to control blood pressure
Erythropoiesis-stimulating agents for anemia associated with CKD
Appetite stimulants if food intake declines
Regular monitoring — bloodwork every three to six months for stable patients — is essential to track progression and adjust treatment.
For AKI, treatment requires hospitalization with aggressive intravenous fluid therapy and treatment of the underlying cause.
Prognosis: What to Expect
Prognosis depends heavily on stage at diagnosis, the underlying cause, and how well the dog responds to management.
Dogs diagnosed at Stage 1 or 2 and started on appropriate treatment can often live months to years with good quality of life. Stage 3 carries a more guarded prognosis, with survival time ranging from weeks to years depending on individual response. Stage 4 is generally associated with a poor short-term outlook, with management focused on comfort and quality of life.
Because CKD is progressive, the goal of treatment is to slow the rate of decline rather than stop it. Consistent veterinary monitoring allows treatment plans to be adjusted as the disease advances.
Does Pet Insurance Help Cover Kidney Disease in Dogs?
Kidney disease — whether AKI or CKD — is typically classified as an illness under accident and illness pet insurance plans. Coverage may help with the eligible costs of diagnostic testing, prescription medications, hospitalization, and ongoing monitoring appointments.
What pet insurance covers varies by plan. Pre-existing condition exclusions apply, which is why enrolling before symptoms develop, including any waiting periods, is important — particularly for breeds at higher risk or for dogs entering their senior years. Plans that cover senior dogs with no upper age limit can help give pet parents more flexibility when a diagnosis like CKD comes later in life. As with other serious chronic conditions, having a plan in place before illness arises can help make a meaningful difference in what care is financially accessible.
The cost of pet care can add up quickly, especially during emergencies or for ongoing treatment. Choosing a plan with affordable monthly premiums and a simple reimbursement process can help reduce financial stress.
With Spot Pet Insurance, pet parents can access customizable plans designed to fit different budgets. Spot has paid back over $530 million in covered vet bills and offers quick claims processing, helping pet parents get reimbursed faster for eligible expenses.
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International Renal Interest Society (IRIS). “IRIS Staging System.” https://www.iris-kidney.com/iris-staging-system
VCA Animal Hospitals. “Chronic Kidney Disease in Dogs.” https://vcahospitals.com/know-your-pet/kidney-failure-chronic-in-dogs
Today’s Veterinary Practice. “Treatment Guidelines for Chronic Kidney Disease in Dogs and Cats.”
The information presented in this article is for educational and informational purposes only and does not constitute or substitute for the advice of your veterinarian.
