Activity Transcript

Speaker 1: This program is presented by Medscape Education Global.

Peter Lin, MD, CCFP: Hello, I'm Dr. Peter Lin. I'm a family doctor and director of the Primary Care Initiative at the Canadian Heart Research Center in Toronto, Canada. Welcome to this program titled “The Real Impact of CKD in Primary Care: Let's Quiz the Expert.” So, it's going to be short, quick, snappy questions, and hopefully short, quick, snappy answers as well. And our expert today is Dave Cherney. He's a super expert, world renowned, and also a good friend. He's professor of medicine at the University of Toronto, clinician scientist in the division of nephrology at the UHN. He's also senior scientist in Toronto General Hospital, and he is a research industry director of the Renal Physiology Laboratory at UHN in Toronto, Canada. So, basically anything that has to do with the kidney has somehow passed through his hands and you see his name on many, many publications. So welcome Dave, thank you very much for your time today.

David Cherney, MD, PhD, FRCPC: Good to be here with you, Peter. Thanks very much.

Dr Lin: That's fantastic. So, I know the kidney is a great organ and that's not just because you're sitting here, Dave. It is a great organ in the sense that it just keeps working. It never complains, it just keeps pumping along. And because it never complains, I think chronic kidney disease and CKD is often underdiagnosed or it's diagnosed at the very late stages. So, I think this program is very useful because we're looking for ways of what we could do to identify patients, and then more importantly treat them so we can prevent CKD and avoid all those complications. So, Dave, I know that you live and breathe kidneys. For us, it's one of the organs. Let's start off with how common is CKD in the world, let's say?

Dr Cherney: So, thanks very much for the question, Peter. So, chronic kidney disease is unfortunately very common, and it's estimated that approximately 700 million people around the world have chronic kidney disease. And chronic kidney disease is important because of its associations with other illnesses that we'll talk about today, including cardiovascular disease and an increased risk of death over time. Chronic kidney disease is also associated with a diminished quality of life, and as I mentioned, with an excess in mortality, so a reduction in life expectancy. And in large studies including upwards of 7 million people around the globe, it's estimated that about 13% of patients around the world have any stage of chronic kidney disease, so anywhere from stage 1 to stage 5. Stage 1 of course being the most preserved kidney function, stage 5 being the most severe form of kidney disease towards the range of needing dialysis.

And about 10% of people around the world have chronic kidney disease that's in a stage 3 to 5. So clinically significant, stage 3. So that's a GFR of 60 or below, meaning that it's an extremely common condition around the world.

Dr Lin: So, huge numbers that you're talking about. And you started to talk about the impact of CKD on patients. So, what kind of impact does this disease have on our patients?

Dr Cherney: Yeah, so chronic kidney disease is indeed a leading cause of death worldwide, and the global mortality rate associated with chronic kidney disease has increased over the last 2 to 3 decades. So, this is becoming a more and more important problem over time. And one of the major reasons that chronic kidney disease is linked with an increased risk of cardiovascular disease and with mortality is that there are many common mechanisms and harmful effects of kidney disease that affect the kidney and also affect the cardiovascular system. Type 2 diabetes as one of them, and the associated high levels of blood sugar are linked with kidney damage and with cardiovascular disease. But there are also other factors, including retention of salt and water, hypertension, and other factors that damage both the kidney and the heart and leads to this link and association in terms of mortality and risk.

And then the other thing to mention that's important is that kidney disease is not only associated with cardiovascular disease, it's also associated with many other conditions. It's associated with bone disease, with anemia, with abnormalities in electrolytes including hyperkalemia, and other factors that make it very complex to manage these patients. So, the other thing to think about in patients with kidney disease is to look for all these complications, especially at that tip of the iceberg where patients have reached stage 5 kidney disease.

Dr Lin: So that means kidney disease by itself is doing lots of damage, people dying from that, but on top of other diseases if you have kidney disease, it makes the other diseases much worse. You had mentioned something about diabetes being one of the populations that we should be screening. What other patients should we be focusing on in terms of screening for kidney disease?

Dr Cherney: Yeah, that's a great point. So, I've mentioned type 2 diabetes because type 2 diabetes accounts for somewhere around 40% of patients who end up on dialysis or needing a transplant. So, type 2 diabetes is extremely important and it's probably the most common single factor that leads to end-stage kidney disease. But there are many other factors that are important as well. Those other risk factors include high blood pressure, having cardiovascular disease by itself also increases the risk of kidney disease because if the heart's sick then the heart can't pump enough blood to the kidneys and the kidneys get starved for oxygen and nutrients and that can also cause impairment in kidney function over time. There are also family and inherited related conditions that cause chronic kidney disease. Polycystic kidney disease, for example, and other hereditary kidney diseases.

And then patients who have had previous kidney damage from complications from surgery or other medical conditions are also at high risk of future loss of kidney function over time. And then there are other high-risk groups. So inflammatory kidney diseases are unfortunately quite common too. And then in some parts of the world there are also high-risk occupational exposures that are important to consider. So, it's not only diabetes, there are other causes too, especially hypertension, cardiovascular disease, and inflammatory kidney diseases.

Dr Lin: I think you've just named off every patient that we normally see in our office. Other than the very healthy person that comes in just for their annual checkup or something like that, you basically touched upon all of them, which means that we should have kidney disease high up on our list of things that we should do. And what tests should we be doing to screen these patients for chronic kidney disease? What can we do in primary care, for example?

Dr Cherney: So up until or down to the level of kidney function around 30%, patients often don't have a lot of symptoms. They can have higher blood pressure, they can have the cardiovascular risk, but clinically the kidney disease itself is often silent. So, it does require some tests to be done, including blood and urine tests to identify the kidney disease and how severe it is as well. Fortunately, those tests are quite easy to do. They involve a blood test or a urine test. Blood test is GFR from a creatinine level, and then in the urine it's an albumin to creatinine ratio or UACR, which also identifies patients at risk.

In people with type 2 diabetes, for example, these tests should be done once per year at least to identify patients through screening mechanisms, and then in patients who have more severe degrees of kidney dysfunction, these tests should generally be done more often according to the severity of kidney disease to see how rapidly it's progressing.

Dr Lin: That's good guidance. Now you told us about the eGFR and then the albumin creatinine ratio. How do we put it together?

Dr Cherney: In terms of putting together these numbers in terms of a score, we do have this heat map that the KDIGO recommendations have put together, which I like because it shows where we have to worry less and where we have to worry more. It also tells us a little bit about how to monitor and follow patients.

In patients who have lower risk in green, these are patients with low levels of albuminuria and preserved GFR. Those patients generally have to be followed much less frequently, generally don't have to be referred to a nephrologist, and therapy is often less aggressive in those patients. And as we go from green to yellow to the mustard color to red, those are of course patients where we have to be much more concerned, where we have to monitor much more frequently. So, for example, in patients who were in the red squares, we would have to follow 3, perhaps 4 times per year, especially as patients get down to CKD stage 5. And in those patients in the red squares, we also have to think about are there other complications from their kidney disease? Do they have anemia that we have to treat with iron or with erythropoietin stimulating agents? Do they have a metabolic acidosis that we have to correct? Is there phosphate in their calcium and their vitamin D okay because the kidneys are of course responsible for bone health. So, those are all the things that we have to take into consideration when looking at this heat map and not just thinking about the degree of severity but also how we have to act to reduce risk and also reduce the halo of other complications that can develop in patients who have kidney disease as the primary problem that they are presenting with.

Dr Lin: Yeah, that's a good point. So, with those 2 numbers, you've got them on the 2 axes, the eGFR and also the urine albumin. And thankfully they did color coding that we all understand, red is bad, and green is good. Now there was also a risk calculator of some sort that you had mentioned before.

Dr Cherney: Yeah, so there are ways of calculating what future risk is of progression and future risk of dialysis, and there are different calculators that are out there, but one of the most common is the KFRE equation, which was developed to understand what the 1, 5, and even longer-term risk is of kidney disease in terms of needing dialysis. So, you can go onto the KFRE equation website and put in numbers including age, sex, and the GFR and the urine albumin excretion, and that gives an idea of what the 1 and 5-year risk is of end stage kidney disease.

And why that's important is that patients who have a certain threshold of kidney disease progression, somewhere around 10%, those patients are often eligible for additional resources. So, they're often eligible to be taken care of in a multi-care kidney clinic where there's a doctor, there are nurses, there's a pharmacist, social worker, and other allied health professionals that are available to help give strategies to both educate our patients around their kidney disease and how to prevent it and also to support them if kidney disease does progress to make sure they're ready for dialysis or a transplant. So those numbers are important to understand risk, but also helps to guide therapy and get our patients more resources in many places around the country.

Dr Lin: That's actually a good way to phrase it. And then once we identify these people, I guess what are the treatments that we can do? I think most of us have focused on blood pressure and ACE inhibitors or something like that, but what's the plethora of treatments now available to our kidney patients?

Dr Cherney: So, think about this in terms of 2 broad categories. One is lifestyle changes and then the other is pharmacological therapies. So, in terms of lifestyle changes, it's all the things that we typically recommend for good cardiovascular health. Those recommendations also extend to the kidneys because of the interaction and interplay between factors that cause kidney disease and cardiovascular disease. So that includes stopping to smoke. Maintaining a healthy diet that's appropriate for the kidneys is also important as well as a healthy weight. We know that obesity is associated with kidney injury and with albuminuria, and so weight loss is often an important strategy to reduce kidney disease progression including regular exercise. And finally avoiding some of those nephrotoxic medications or other agents including NSAIDs, anti-inflammatories, as well as herbal medications and other substances that can damage the kidneys. So that's lifestyle. And then on the medical pharmacological side, we know that blood pressure control is important. Control of diabetes is also absolutely critical, both with lifestyle and with pharmacological therapies. ACE inhibitors or angiotensin blockers, those are important for blood pressure control and also to reduce proteinuria and kidney disease progression.

And then more recently we have SGLT2 inhibitors for both people with and without diabetes to prevent kidney disease progression. And then finally we have mineralocorticoid receptor antagonists like finerenone that have been shown to also be beneficial in people with type 2 diabetes who have kidney disease, there is also significant evidence showing a reduction in both cardiovascular and kidney risk. So those are some of the important medical interventions in addition to controlling cardiovascular risk with statins and other therapies that we would typically use in patients with type 2 diabetes.

Dr Cherney: So, from your perspective, if I can ask you a question about follow up, we get all kinds of referrals about follow up of patients with kidney disease across a range of GFR and across a range of albuminuria. How do you decide when to refer to a nephrologist?

Dr Lin: When I run out of my bag of tricks, then I refer, because I don't know what else to do. If I certainly see anything abnormal, that's not in the normal realm of let's say normal diabetic kidney disease, that slow progressive decline, if I see a sudden drop in eGFR or a large amount of protein in the urine that I can't explain, blood in the urine, or if let's say the hypertension is not responding now, is resistant, are we talking about a secondary cause of hypertension, that kind of thing. If there's hyperkalemia, so high potassium that doesn't make any sense, that's lethal. So therefore, we have to send those off.

And if somebody has lots of kidney stones, we've actually discovered many parathyroid hormone tumors after we send them off. And hereditary kidney disease, as you mentioned, that runs in families, those are the things that are not normal run of the mill. So, for those ones I turn to Dave, and I say, "Here, take my patient." So hopefully I'm not overburdening you, but at least I'm giving the ones that I think need the specialty care. And then the normal run of the mill, diabetic kidney disease, hypertension kind of versions of things, things that we know how to manage, then we can do that.

I see that our time has run out, and Dave, we could spend another hour speaking with you with your knowledge base but let me just summarize what we've learned from you just in these very short few minutes. CKD is common and it's silent, so therefore we need to go looking for it. We should focus on screening patients, as you mentioned, diabetes, hypertension, cardiovascular disease patients, family history of renal disease, acute kidney injury, or any disease that hurts the kidneys, like for example lupus, chemical exposures. In other words, many of our patients we should be thinking about screening their kidney function.

And we should do it with an eGFR that looks at the speed, and an albumin creatinine ratio that looks at the quality of the filter. And we should use that heat map to tell us where they are, not just to tell us what kind of kidney disease and what risk they're at, but also what things that we have to do for them. In other words, to prevent them from progressing. And that risk calculator is kind of neat. I like the way you say we can get you more resources if we have your risk score done as well.

Avoiding NSAIDs, I've now taken that to heart to make sure patients aren't taking it. And also you re-emphasized the need for RAS blockade, so ACE inhibitors, ARBs, and of course SGLT2 and aldosterone antagonists are the new ones coming on board, which we can use on our patients, and if we do it early on, we might prevent all of these complications. And then of course when I run out of my bag of tricks and the patients are getting sicker, then I refer. And that's always appropriate to refer when you're not sure what to do.

So, Dave, thank you very much for your time and expertise and for all the basic science work that you do and how you can translate it to patients and then more importantly translate it to us. And thank you to our participants for your time, and please help us make these programs better by answering just a few questions and completing the evaluation forms. That really helps us to improve the quality of these presentations. Thank you again for your time, thank you Dave, and we'll see you next time at the next event.

Speaker 1: This program was presented by Medscape Education Global.

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