Chronic Kidney Disease – the “silent” disease
Though CKD is asymptomatic (where you do not sense anything wrong), there are ways to keep it at bay or slow it in its track.
BY: Dr Claude Renaud
Chronic Kidney Disease (CKD) is a silent, progressive and irrecoverable loss in the function of both kidneys over more than three months. Generally, an individual’s kidney function is regarded as normal when it is 60 percent and above.
The function of both kidneys is to filter water, excess acid, certain minerals like potassium and phosphate and body waste products through the urine. They also produce hormones that regulate the health and function of red blood cells, bones and blood pressure. After the age of 40, kidney function begins to fall by approximately one percent per year due to the kidneys’ natural ageing process. However, chronic medical conditions like diabetes, high blood pressure especially associated those with heavy urine protein leakage and heart disease can speed up that loss by as much as eight percent per year.
Kidney disease can affect people of any age or race, but in the developed and developing world, it is those older who are most at risk.
So what is the prevalence rate in Singapore?
According to the Singapore Prospective cross-sectional study by Dr Charumathi et al published in Nephrology Dialysis Transplant (2010) 25: 2564-2570, which looked at 4,500 people in Singapore, 12.8 percent of the screened population has CKD.
Other important trends from the study:
• More than 30 percent of those above 60 years had CKD.
• CKD by ethnicity was as follows – 11.4 percent in Chinese, 18.6 percent in Malays and 17.6 percent in Indians.
• 5.5 percent of people with CKD were in the late Stages 3 to 5. This compares with seven percent in Taiwan, five percent in Korea and four percent in Europe.
Who are most at risk of CKD?
People most at risk of developing CKD are those with poor controlled diabetes and high blood pressure, heart disease and family history of kidney disease, elderly, those who are obese, smokers and those who have had acute kidney problems. Indeed, 60 to 70 percent of CKD cases in Singapore are related to diabetes mellitus.
Diabetics who have heavy protein leakage and whose eyes are also affected by diabetic vessel damage requiring laser treatment usually have a more aggressive and rapid course. Hence, early urine test and eye checks are essential in assessing the extent of vessel damage and may give a clue about the larger risk of kidney disease deterioration.
The rate of deterioration can be slowed if diabetes and blood pressure are well-controlled, smoking is stopped, weight is controlled and strong painkillers and certain traditional medications are avoided.
What are some symptoms of CKD?
CKD is usually asymptomatic, meaning it does not manifest any signs of symptoms. Hence, it is called the silent disease. A person who has CKD may not know he has the disease until his kidney function is significantly impaired – usually below 15 percent. This is because the normally functioning parts of both kidneys can still do the job of the damaged parts up to a certain extent.
At a function of 15 percent there is accumulation of sufficient wastes, reduced red blood cell and bone function as to cause symptoms of general unwellness and tiredness. There may be loss of appetite, nausea and itchiness. Generalised body swelling or breathlessness also develops if there is excess water in the body or lungs.
Accumulation of acid and minerals like potassium is very dangerous and can cause the heart to stop beating if not corrected.
How many stages of CKD are there?
CKD is grouped into five stages. In Stage 1 and 2 is where the function is maintained and there may only be protein or blood leakage in the urine. Stage 3 is clinically important as by that time function is down to less than 60 percent, blood tests start to become abnormal and by right the affected person may need to see a kidney specialist. At stages 4 and 5, there are only 30 and 15 percent of kidney function left respectively. An affected person can progress through the different stages or “appear” at any point. The “journey” can be fast or slow depending on how well risk factors are properly controlled.
What are some lifestyle habits we should adopt to reduce the risk of getting CKD?
For people with diabetes and high blood pressure, it is important to manage their conditions well through exercise, appropriate diet (low salt, low fat and low potassium in some instances), strict compliance to prescribed medications and maintaining a healthy weight.
For healthy individuals, maintaining a healthy weight, exercising regularly and refraining from smoking are sound habits to adopt. Drinking adequate water (three to five glasses a day) prevents dehydration. Strong painkillers, other than paracetamol, can cause kidney damage if taken excessively in someone with normal kidney function or worsen function in someone with established early kidney disease. So avoiding excessive use of strong painkillers, especially by those who suffer from gout or osteoarthritis, is another habit to adopt.
Lastly, as for an elderly or someone with other risk factors, they should go for regular health check-ups.
Dr Claude Renaud is a consultant in the Department of Medicine at Khoo Teck Puat Hospital.