Scott Webb (Host): March is National Kidney Month, and joining me today to tell us more about the kidneys and how nephrologists can help patients is Kara Umbarger. She's an Advanced Practice Registered Nurse with Carle, who specializes in nephrology.

Kara, it's nice to have you here today. I know that March is National Kidney Month, so it's a great time to have an expert on to talk about nephrology and kidneys and all that good stuff. So let's start there. What is nephrology?

Kara Umbarger, APRN: Well first I want to really thank you guys for having me on in honor of kidney month. Nephrology is truly my passion. Nephrology is a specialty and it focuses on the diagnosis, treatment, management of all kidney related disorders.

So that's going to cover conditions such as chronic kidney disease, acute kidney injury, glomerular diseases, hypertension, diabetic kidney disease, electrolyte imbalances. Our nephrologists also manage patients on dialysis and those who have also undergone kidney transplants. So we get to see all these different types of patients in the office, the hospital, and the outpatient dialysis centers.

Host: Sure. Well, it's good to have a foundation there to understand, because we've all heard that word before, but it's like, exactly what do those folks do? So, along the same lines, you know, we all have kidneys, right? Most of us have two kidneys. But I'm not sure that all of us know exactly what our kidneys do.

So from an expert here, what do the kidneys do? What's their function?

Kara Umbarger, APRN: Yeah, so first we'll kind of start off with the kidneys are two bean shaped organs located in the back of the abdominal cavity, and they actually sit up a little bit higher than most people realize. They're kind of up under the back of your ribs. So I think a lot of people think they sit in your lower back, but they actually sit up a little bit higher, and they do have lots of different functions, lots of different jobs.

The main job is homeostasis. So when I started in the nephrology specialty, I was told, think of your kidneys as like a computer system. They maintain balance throughout your whole body. They also filter blood. So the main thing that most people know, they filter blood, they remove waste products, remove toxins, and they maintain fluid balance.

They also do electrolyte and acid-based regulation, so this means they control the levels of sodium, potassium, calcium, phosphorus, bicarbonate, and then they also play a big role in blood pressure regulation. So they do this through what we call the renin angiotensin aldosterone system. And then they actually also help with a couple different hormones.

So your kidneys secrete erythropoietin, and this actually stimulates red blood cell production. And they also help to activate vitamin D into an active form that our body can use. And this is really beneficial for bone health. So in our specialty, we get to kind of manage all these different functions and make sure your kidneys are doing everything they're supposed to be doing for the body.

Host: Sure. Yeah. And like many things in our body, the kidneys wear a lot of hats, right.

Kara Umbarger, APRN: Yes.

Host: They, they do a lot and they're really essential and we want them to be working properly. So, what are some maybe updates you have in just overall kidney care?

Kara Umbarger, APRN: Okay, so in nephrology we tend to follow the KDIGO guidelines. This is kidney disease, improving global outcomes, and this guideline as a whole was updated in 2024, and then certain sections of it were updated in 2025. I'm sure there's going to be certain updates this year, but one of the major updates, and I'm sure Carle also noticed this, was an updated GFR equation, so the GFR glomerular filtration rate.

This tells us the percentage the kidneys are functioning. So we updated this to the CKD Epi 2021 equation and this took the race-based adjustments out of the equation. So, it kind of gives everyone a more accurate representation of the function of their kidneys. Some facilities are moving more towards using cystatin C, and this might be something that comes in the future just for more accuracy. And then another big update is SGLT2 inhibitors are now recommended as first-line therapy to slow the progression in chronic kidney disease for both diabetic and non-diabetic patients. This is huge. There's been so many new updates in our specialty. It's been actually really exciting. Before the SGLT2 inhibitors, we still recommend ACE and ARBs as our foundation and then the SGLT2 inhibitors. But it's just really exciting because I don't think there's been anything in our guidelines since the ACE or ARB. So those are probably the two biggest updates.

Host: Yeah. And it's always nice to hear just whatever we're talking about, whatever medical topic, you know, it's just nice to hear that great things are happening. That's great for patients and providers and everybody involved. And you touched on earlier you said that the kidneys regulate blood pressure.

So I want to just get a sense from you when we think about hypertension and kidney disease, like how do those things go together?

Kara Umbarger, APRN: For chronic kidney disease, the two most common causes are diabetes and hypertension. And in our specialty, we really focus on resistant hypertension. And I actually, I'm part of the National Kidney Foundation, so I get monthly magazines, so, it's the Helio Nephrology. And I don't have to worry about my family stealing these ones.

But in the November issue, it said between 1999 and 2023, hypertensive renal disease was associated with 274,667 deaths among people age 15 years and older. So hypertension, it's a big problem and it damages the kidneys. So in our nephrology specialty, we do really focus on resistant hypertension, and this has actually become a big interest of mine.

It's prompted me to kind of further my education. And I've actually become a certified hypertension clinician through ASHCP, just to best serve my patients. So anyone in primary care who is having difficulty controlling their patient's blood pressure, seeing resistant hypertension, new onset hypertension, or they're just not sure what medication to start next, they can always refer over to us. We are happy to help.

Host: Yeah, and it's good to hear that you don't have to share your magazines, that those are they, they may take your People magazine, but they're not taking the kidney. Well, you know, the, those are all there for you. That's awesome. Well, a great update today. I just kind of want to finish up and give folks a sense of when they would see a nephrologist or when a primary care doctor might refer to nephrology.

Kara Umbarger, APRN: As far as referring to nephrology, usually we like to see patients diagnosed with chronic kidney disease. So this is GFR of less than 60 for three consecutive months. We see patients for acute kidney injury or any sudden drop in their GFR, persistent proteinuria, so this is protein in the urine.

We definitely want those patients referred early. Any abnormalities with electrolytes, so that includes serum potassium, sodium, calcium, phosphorus, magnesium. We see patients and we want them referred over for secondary hyperparathyroidism, metabolic acidosis, like we talked about earlier, resistant hypertension, so this is high blood pressure that's resistant to treatment with three or more medications at maximum dose. We also see patients for recurrent or extensive kidney stones, for anemia of chronic disease, hereditary kidney disease and then post kidney transplant. So all of these are reasons to refer patients over to our specialty.

We would rather get them referred over early so we can start taking care of them.

Host: Sure. Yeah. And as much as we said earlier, the kidneys wear a lot of hats, do a lot of stuff, important things, functions in our body. Nephrologists obviously, a wide gamut of things that you all can do and help patient's with. So, good stuff today. Thank you so much.

Kara Umbarger, APRN: Thank you for having me.

Host: For more information and to get connected with one of our providers, please visit carle.org. And that wraps up this episode of Expert Insights with the Carle Foundation Hospital. I'm Scott Webb. Stay well.