With society’s increased focus on wellness and disease prevention, management of stone recurrence presents an opportunity for clinicians to help prevent stone patients from suffering additional attacks. In this interview, Juan Calle, MD, discusses how he follows patients once they are stone free, how he utilizes dietary/lifestyle modification and medical management, and his advice for young urologists looking to become experts in stone recurrence. Dr. Calle is medical director of the Kidney Stones Clinic at Cleveland Clinic. He was interviewed by Urology Times Editorial Consultant Stephen Y. Nakada, MD, the Uehling Professor and founding chairman of urology at the University of Wisconsin, Madison.
Please define stone recurrence.
The way I look at it, and the way I talk to patients, residents, and fellows about it, is that stone disease is a chronic disease. It doesn’t go away. Kidney stones used to be seen as something that occurred as an isolated case and maybe happened once in a blue moon afterwards. Nowadays, we know that’s not the case. It’s a disease that can come back. If a patient has an initial kidney stone attack, they may actually have another stone forming, depending on the type of stone and the conditions of the patient, they may have recurrence of stone disease within a couple of years. Sometimes the stone-free period lasts longer.
On average, around 30% to 50% of patients, depending on the studies you look at, may have recurrence or another stone attack within 3 to 5 years. There are actually reports dating back more than 30-40 years suggesting that the recurrence of stone disease is 100%. I tell patients that in around 30% to 50% of the cases, they have a high chance of having recurrence 2-5 years after the initial stone.
How important is obtaining stone composition?
I give a lot of importance and weight to stone composition because sometimes we may tailor our recommendations to patients in terms of diet and stone preventive medications based on stone composition. There are some basic recommendations that apply to all patients, but composition is still very important because sometimes we may discover rare kidney stone types. There are some genetic abnormalities that can influence the formation of stones or there may be associated genetic abnormalities that are potentially treatable.
Now, if you’re a betting person, you know that more than 70%-80% of stones are going to be calcium based, and of those, more than 70%-80% are probably going to be calcium oxalate. So although most kidney stones you analyze are going to be calcium oxalate, it’s still important to determine their composition.
Let’s say someone has a stone, they pass it, and they are stone free. What’s your follow-up plan to seek recurrence? At what interval do you obtain studies, and what studies do you get, if any?
It’s very dependent on each case. I put a little more emphasis on those patients who start forming stones at a very early age. If it’s their first stone and they haven’t had any other complications or any other major comorbid conditions, sometimes just general recommendations will do. It’s also age dependent. If the patient is a middle-aged man or woman and they have had only one stone in their lifetime and they have some risk factors that I think we can handle with diet or lifestyle, we may not even need to do a comprehensive panel of a 24-hour urine collection or something along those lines. As a nephrologist, I always check their kidney function, and for almost all patients, I also check on their electrolytes just to make sure there is no major abnormality that we’re missing. Now, if patients have had kidney stones in the past or have any other condition—those who have undergone kidney transplant, patients with a single kidney, and so on—those are patients I will place more of an emphasis on.