RBT Interview: Understanding the Burden of CKD

Editor’s Note: Kovesdy is chief of nephrology, Salem VA Medical Center in Salem, Va., and assistant professor of Clinical Internal Medicine at the University of Virginia in Charlottesville. Pre-dialysis chronic kidney disease is his main research interest.

Can early chronic kidney disease be considered a public health burden?

It’s fashionable to talk about it that way. The reason for that is the NHANES data that estimated that possibly 20 million people in the U.S. suffer from some degree of CKD. The proportion is high enough to merit attention at the population level. The other reason is financial. You need not look further than the proportion of the Medicare budget spent in ESRD relative to the number of the patients. The vast majority of the patient population are non-dialysis dependent, and the expense burden increases tremendously once they are on dialysis. Even those who are not on dialysis yet, tend to have higher comorbidity burdens, higher hospitalization rates and represent a very significant financial burden.

What is the clinical burden for a CKD patient? Do people know what that is?

I don’t think they do. The mortality rate increases tremendously with increasing stages of CKD. When compared to the general population, any study you look at shows that these patients have a higher rate of diabetes, hypertension, and cardiovascular disease. The average prevalence of these comorbidities in the core that I’m studying, we have about 55 percent diabetes and about 60 percent prevalent cardiovascular disease. And more than 90 percent of them are hypertensive. It gives you the idea that these are much higher than the general population. All these things add up.

If someone can get detected for CKD earlier, would it be beneficial in terms of treating all the other complications at the same time, just using CKD as a starting point to figure out who needs more help?

That’s an interesting concept that has recently been thrown around quite a lot. The question is what to do with these patients? On one hand, diagnosing CKD can be easy if you consider that all you need to do is check a serum marker for kidney function. The problem with creatinine is that it’s not the best marker. You can estimate GFR—that’s slightly better—but not so in patients in earlier stages. You would not only have to check the blood or serum level, but also concomitantly check urinary indices. By doing this you could identify a high-risk group of patients where you could screen more closely for hypertension, diabetes and cardiovascular disease. It’s certainly something that has merit, but it’s sort of sketchy to how we would deal on a population level with 20 million patients like this.

As we introduced the estimated GFR, clearly a lot of people who used to get by without being tagged as CKD are now identified as having CKD. That has resulted in a quite remarkable increase in consultation requests from primary care facilities to nephrology specialists for CKD, purely based on an estimated GFR that falls below a fairly arbitrary threshold of 60 for CKD stage 3. As a practicing nephrologist, probably a significant proportion of those, we really don’t do anything about because they tend to be elderly people who have no room for any additional intervention and have modest degrees of CKD and they’re not progressive.

The question is what would you do if you were able to diagnose all 20 million people who have CKD? Would you refer them to see a nephrologist?  I don’t think the 5,000 nephrologists in the U.S. could handle that burden. It is really unclear how you could narrow down that pool of 20 million to that core who has more progressive disease, where you have a more complex conditions that would ask for the expertise of a nephrologist. Going from a population level, simple diagnosis of CKD to actual management, I think it is very important to refine our diagnosis and better identify those patients who really need additional interventions beyond just diagnosing slightly decreased kidney function.