Chronic Kidney Disease

Your kidneys filter waste and extra fluid out of the blood, help control blood pressure, and keep minerals in balance. Chronic kidney disease means that filtering has been reduced for at least three months. In the early stages there is usually nothing to feel, and later on it can show up as tiredness, swollen ankles, foamy urine or broken sleep.

What chronic kidney disease is, and what it is not

Chronic kidney disease is not the same as kidney failure, and it does not mean dialysis is coming. It is graded in stages from 1 to 5, based on how well the kidneys filter and how much protein leaks into the urine, and most people in Canada are at the early stages. Kidney Foundation data show that roughly 60% of people with the condition are at stage 1 or 2, where the aim of care is to protect the kidney function you have.

It is also not something you would notice on your own. More than 90% of early stage chronic kidney disease in Canada goes undiagnosed, and about 40% of people who do have it are already at stage 3 or beyond by the time it is found. That is why kidney checks are built into routine care for people living with diabetes, high blood pressure or heart disease, rather than waiting for symptoms to appear.

Signs and symptoms

• Often no symptoms at all in the early stages
• Feeling tired, weak or short of breath
• Swelling in the ankles, feet, hands or around the eyes
• Passing urine more often at night, or less often than usual
• Foamy or bubbly urine, which can mean protein is leaking
• Poor appetite, nausea, a metallic taste, or trouble sleeping
• Itchy skin, muscle cramps, and trouble concentrating

Symptoms tend to appear late and to build slowly, so many people put them down to age or a busy life before the cause is identified.

What raises the risk

Some risk factors cannot be changed:

• Getting older
• A family history of kidney disease, including inherited conditions such as polycystic kidney disease
• Ancestry, since Indigenous, Black and South Asian communities in Canada are affected more often and at younger ages
• A history of acute kidney injury

Others can often be worked on, usually with support from a health care team:

• Diabetes, which is the most common cause of kidney failure in Canada
• High blood pressure
• Smoking, and living with obesity
• Heart disease, and repeated use of some medicines such as anti-inflammatory painkillers, which is worth reviewing with your doctor

How chronic kidney disease is diagnosed in Canada

Two simple tests find it, and a family doctor or nurse practitioner usually orders them together. A blood test measures creatinine and is used to calculate the estimated glomerular filtration rate, or eGFR, which shows how well the kidneys are filtering. A urine test measures the albumin to creatinine ratio, which shows whether protein is leaking. Results have to stay abnormal for at least three months for the diagnosis, and an ultrasound of the kidneys, further blood tests, or referral to a nephrologist may follow depending on the stage and the suspected cause.

Treatment and day-to-day management

Clinical research for Chronic Kidney Disease is enrolling. See the current studies ↓

Most care is aimed at slowing the decline in kidney function and protecting the heart at the same time, since the two travel together. Depending on your stage, your cause and what else you live with, a health care team may discuss:

• Blood pressure lowering medicines, especially ACE inhibitors and angiotensin receptor blockers
• SGLT2 inhibitors, and non-steroidal mineralocorticoid receptor antagonists such as finerenone
• GLP-1 receptor agonists and other diabetes medicines when diabetes is the underlying cause
• Supportive medicines for the effects of reduced kidney function, including treatments for anemia, phosphate and potassium levels and bone health, along with input from a renal dietitian
• Kidney replacement therapy, meaning hemodialysis, peritoneal dialysis or a kidney transplant, and conservative kidney management for people who choose not to start dialysis

Diet advice in particular depends on your own blood tests and stage, which is why general advice found online can be misleading. What fits you is a decision for you and your own clinician or kidney care team.

When to talk to a doctor

• Call 911 for chest pain, severe shortness of breath, confusion, seizures, or an inability to pass urine at all, since these can signal a kidney or heart emergency.
• Seek urgent care for sudden swelling of the face, legs or abdomen, or for a sharp drop in how much urine you are passing.
• Book with your family doctor if you live with diabetes or high blood pressure and have not had a blood and urine kidney check in the past year, or if you notice persistent foamy urine, ongoing fatigue or new ankle swelling.

Why clinical research matters for chronic kidney disease

Most chronic kidney disease in Canada is not identified until damage is permanent, kidney function keeps declining for many people despite current treatment, and dialysis takes a heavy toll on daily life. Studies now recruiting are looking at newer agents that act on kidney scarring and inflammation, endothelin receptor antagonists, complement inhibitors for immune-driven kidney diseases such as IgA nephropathy, aldosterone synthase inhibitors, and the wider use of SGLT2 inhibitors and non-steroidal mineralocorticoid receptor antagonists in people who do not have diabetes. Other work covers home dialysis technology, transplant immune therapy that avoids long-term rejection drugs, xenotransplantation, and screening strategies to find kidney disease earlier in primary care.

All of that depends on clinical studies, and on people who agree to take part. Participation is voluntary, informed consent comes before anything begins, and you can withdraw at any point without affecting the care you get from your own doctor or kidney clinic. No one can say in advance whether a study will help you personally.

Learn more from Canadian sources

• The Kidney Foundation of Canada
• Diabetes Canada
• Hypertension Canada
• Heart & Stroke