Stages of Kidney Disease in Dogs: A Guide for Pet Parents

If your dog has been diagnosed with chronic kidney disease (CKD), one of the first things your vet will tell you is what stage they’re at. That staging isn’t just a number, it shapes everything from treatment decisions to what symptoms to watch for. This guide walks through each stage clearly, so you know what you’re dealing with and what you can do at every point along the way.

What is chronic kidney disease in dogs?

Chronic kidney disease (CKD) is a long-term condition where the kidneys gradually lose their ability to filter waste, balance fluids, and regulate key minerals in the body. Unlike acute kidney injury, which comes on suddenly and can sometimes be reversed, CKD develops slowly over months or years. It’s most common in older dogs, though some breeds are predisposed to developing it earlier.

The important thing to understand about CKD is that kidneys have a lot of reserve capacity. By the time symptoms appear, a significant amount of kidney function has often already been lost. That’s why the staging system and regular monitoring matter so much.

How is CKD staged?

Vets use the IRIS (International Renal Interest Society) staging system to classify CKD into four stages. Staging is based on two key blood markers:

• Creatinine: A waste product that builds up in the blood when the kidneys aren’t filtering properly. Elevated creatinine is a well-established sign of reduced kidney function, but it tends to rise only after significant function is already lost.
• SDMA (symmetric dimethylarginine): A more sensitive marker that can detect kidney disease earlier than creatinine, sometimes when as little as 25% of kidney function has been lost. By comparison, creatinine typically rises only when 65 to 75% is already gone.

Each stage is also sub-staged based on two additional factors:

• Proteinuria: Protein leaking into the urine, which shouldn’t normally happen and indicates additional kidney stress.
• Blood pressure: Hypertension is both a cause and a consequence of CKD, and it significantly affects how the disease progresses.

Together, these four markers give your vet the clearest possible picture of where your dog’s kidneys are at.

Stages of kidney disease in dogs

Stage 1: Early kidney changes

At Stage 1, kidney function is reduced but creatinine levels are still within the normal range. SDMA may be mildly elevated, which is often the first detectable sign that something is changing. Most dogs at this stage show no symptoms at all, which means Stage 1 CKD is usually picked up through routine bloodwork rather than because something seemed wrong.

The main focus at this stage is identifying and addressing any underlying causes, things like dental disease, high blood pressure, or a previous kidney injury. Diet changes are generally not started at Stage 1 unless there are specific reasons to do so.

Stage 2: Mild kidney dysfunction

Creatinine levels are now measurably elevated, and SDMA is more clearly raised. Some dogs start showing subtle signs at this stage: drinking a little more water, urinating more frequently, or seeming slightly less energetic than usual. Others still appear completely normal.

Stage 2 is often when dietary management begins. Your vet may recommend a renal diet that avoids excess protein and manages phosphorus intake, reducing the workload on the kidneys. Monitoring becomes more regular from this point, and any proteinuria or blood pressure issues will be actively managed.

Stage 3: Moderate to advanced kidney dysfunction

By Stage 3, symptoms are harder to miss. Most dogs are showing noticeable signs: reduced appetite, weight loss, increased thirst and urination, lethargy, and sometimes vomiting or mouth ulcers. Creatinine levels are significantly elevated, indicating that a substantial portion of kidney function has been lost.

Management becomes more involved at this stage. Your vet will likely recommend:

• A renal prescription diet with controlled protein and phosphorus
• Subcutaneous fluids, which many pet parents learn to administer at home, to help keep the kidneys supported between vet visits
• Medications to manage nausea, blood pressure, and protein loss in the urine
• Phosphate binders to reduce how much phosphorus is absorbed from food
• More frequent monitoring visits to track changes and adjust the plan

Stage 4: Advanced kidney disease

Stage 4 means kidney function is critically low. Symptoms are often severe at this point: extreme lethargy, persistent vomiting, very little interest in food, and sometimes neurological changes. This is genuinely hard to be in the middle of, and it’s okay if it feels overwhelming.

The focus at Stage 4 shifts from slowing the disease to keeping your dog as comfortable as possible. That means intensive supportive care, close symptom management, and honest conversations with your vet about quality of life. There’s no right or wrong answer about how to approach this stage. It’s about what’s best for your dog and your family, and your vet is there to help you think through it.

Diagnosing chronic kidney disease in dogs

If CKD is suspected, your vet will typically start with:

• Blood panel: To measure creatinine and SDMA levels and check for other signs of kidney stress.
• Urinalysis: To assess how well the kidneys are concentrating urine, and to check for protein in the urine.
• Blood pressure measurement: Hypertension is common in CKD and needs to be monitored and managed.
• Ultrasound: To assess the size and structure of the kidneys and rule out other conditions.

Once diagnosed, regular monitoring is a key part of living with CKD. How often will depend on the stage. Early-stage dogs may only need check-ins every few months, while later-stage dogs may need more frequent visits.

Treatment options by stage

Rather than a one-size-fits-all approach, CKD treatment is built around where your dog is in the disease and how they’re responding. Here’s a general overview:

Stage	Primary focus	Common interventions
Stage 1	Identify and treat underlying causes	Address dental disease, infections, or hypertension; increase monitoring frequency
Stage 2	Slow progression, manage early symptoms	Renal diet, blood pressure management, proteinuria treatment if present
Stage 3	Symptom management, kidney support	Renal diet, subcutaneous fluids, medications for nausea and blood pressure, phosphate binders
Stage 4	Comfort and quality of life	Intensive supportive care, frequent monitoring, honest quality-of-life conversations with your vet

Does pet insurance cover kidney disease in dogs?

Yes, chronic kidney disease is covered under Lemonade Pet’s base accident and illness policy, as long as the condition isn’t pre-existing. That includes eligible costs like diagnostic testing, medications, and fluid therapy that are typically part of managing CKD long-term. It’s worth noting that prescription food isn’t covered under Lemonade’s policy, so specialized diets will be an out-of-pocket cost to factor in alongside your coverage.

CKD is a condition that requires ongoing care, and the costs add up over time. Having a policy in place before any symptoms appear means that as the condition progresses, cost isn’t the thing driving your decisions.

Before we go

CKD is a long road, but dogs who are diagnosed early and managed consistently can do really well for a long time. Staying on top of regular bloodwork, keeping vet appointments, and adjusting care as things evolve are what make the biggest difference. If you don’t have a pet insurance policy in place yet, it’s worth taking a few minutes to get a quote. Having coverage before anything develops puts you in a much stronger position when it matters most.

Frequently Asked Questions

A few quick words, because we <3 our lawyers: This post is general in nature, and any statement in it doesn’t alter the terms, conditions, exclusions, or limitations of the policies issued, which differ according to your state of residence. You’re encouraged to discuss your specific circumstances with your own professional advisors. The purpose of this post is merely to provide you with info and insights you can use to make such discussions more productive! Naturally, all comments by, or references to, third parties represent their own views, and Lemonade assumes no responsibility for them. Coverage may not be available in all states. Please note that statements about coverages, policy management, claims processes, Giveback, and customer support apply to policies underwritten by Lemonade Insurance Company or Metromile Insurance Company, a Lemonade company, sold by Lemonade Insurance Agency, LLC.  The statements do not apply to policies underwritten by other carriers.