#BTColumn – Chronic kidney disease – another silent killer in our midst

hronic kidney disease (CKD) is a severe and irreversible condition that leads to a progressive loss of kidney function. In the early stages, it may be completely asymptomatic, perhaps until around 75 per cent of the kidney tissue is completely damaged. Since persons are usually born with two kidneys, this corresponds to the loss of one and a half kidneys.

In the latter stages, called end-stage renal disease (ESRD) patients rely on regular dialysis or a kidney transplant for survival. As kidney function decreases, cardiovascular risk also greatly increases. In fact, patients who develop CKD are more likely to die from a cardiovascular condition like a heart attack, heart failure or a stroke, than to progress to ESRD.

Global statistics show that CKD has almost doubled in the last two decades, fuelled by rising obesity, diabetes, and hypertension. These factors are all at play in local Caribbean populations, but we do not have a close handle on our statistics. But even with limited statistics, the information that we have suggests we have big and growing problems.

In 2017, for example, Barbadian taxpayers spent $19 million on dialysis services at the Queen Elizabeth Hospital, almost 13 per cent of the hospital budget, making CKD probably the single most expensive disease here, perhaps even outstripping treating diabetic foot problems. For both of these conditions, in spite of the high costs associated with the care, many patients do not survive for many months after diagnosis, and many never regain sufficient health that they can become productive members of our society. Unfortunately, in spite of significant efforts and money spent trying to help these patients, many also die.

The QEH has to outsource dialysis support, as its own Artificial Kidney Unit (AKU) cannot adequately serve the demand of patients who need dialysis services, currently about 350, and about three to five new patients are referred for dialysis services, every week. Prior to getting a donation of two kidney units about two weeks ago, the AKU was able to service about 170 patients annually.

One study done almost 30 years ago by the Chronic Disease Research Centre (CDRC) [now the Sir George Alleyne CDRC] of over 2000 primary care patients in Barbados with diabetes and/or hypertension, showed that in less than one per cent of these patients was there any evaluation of the patient’s kidney status. In fairness, it was not known at the time that much could be done for anyone who developed CKD. However, in the intervening decades, many low-cost advances were made in the detection and treatment of CKD. Since the consequences are so severe, perhaps it is time to revisit the local situation in Barbados. Even in the presence of high-risk factors such as diabetes or high blood pressure, CKD screening tests may not be frequently performed.

However, CKD never made it onto the list of chronic non-communicable diseases (NCDs), and thus our health leaders did not place priority consideration on prevention and early detection of this severe progressive illness.

A simple blood and urine test, both inexpensive, where an estimated glomerular filtration rate (eGFR), a test of kidney function and protein levels in urine are determined by a primary care physician, can help ensure that patients heading toward severe kidney disease are identified and treated early. The fact that this early identification rarely happens is tragic, as effective medications have been available for several years that can delay the progression of CKD, especially in the early stages. CKD should be diagnosed in a timely manner.

Two classes of anti-hypertensive medications, the ACE inhibitors and the ARB blockers, both available here and available to patients here on the National Drug Formulary, can slow the progression of CKD. A newer class of medications, the SGLT-2 inhibitors, was originally developed as oral antidiabetic agents, but they were found to have positive effects on the heart and kidneys. Various studies have shown that SGLT-2 inhibitors can significantly slow the progression of kidney function loss.

Some relief in slowing the progression of CKD is now available in another new class of medications called the mineralocorticoid receptor antagonist (MRAs). One of these, in particular, has been shown to be effective in preventing the progression of diabetic kidney disease is the new nonsteroidal, selective mineralocorticoid receptor antagonist drug called Finerenone, available here in the last few months

Another new therapy option is the so-called weight loss injection. Weight reduction reduces the risk for secondary diseases such as high blood pressure and diabetes mellitus, which can lead to CKD. It also has been shown that semaglutide, one of these new weight-loss drugs, slows the progression of kidney disease in patients with diabetes mellitus. In addition to protecting the kidneys by improving blood pressure, blood sugar, and body weight, semaglutide directly inhibits inflammatory processes in kidney cells, thereby protecting the kidneys of patients. In Barbados, the semaglutide injection is available but is probably outside the budget of many patients or the Barbados Drug Service.

Early detection and screening of kidney function not only make sense, and can save money and lives, but also should become mandatory, especially in diabetic and hypertensive patients. The earlier CKD is detected, the earlier an appropriate therapeutic plan can be implemented. And the earlier a plan is implemented, the greater the likelihood of a successful outcome. Because CKD can be treated better when it is detected earlier, screening for CKD should be part of all annual health examinations.

Dr Colin V Alert is a family physician and former researcher with the Chronic Disease Research Centre.