In this interview, Juan Calle, MD, discusses how he follows patients once they are stone free and how he utilizes dietary/lifestyle modification and medical management.
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.
Next: Who do you think needs medical management once they’ve had a stone?In general, who do you think needs medical management once they’ve had a stone?
Mainly, I use medical management for patients who have had either recurrence of stone disease, have bilateral stones, or who may have any major genetic or anatomic abnormalities that predispose them to have greater recurrence risk. I also usually recommend medical management in patients for whom we have done the full metabolic workup and found very abnormal risk factors that could be treated with medications.
Does diet play a significant role in your practice?
Yes, definitely. I discuss goals for urinary output with every patient. I tell them that any patient who has formed a kidney stone should be aiming for at least two and a half to three liters of urine coming out per day. Obviously, this depends on their size, gender, and whether they have any other medical conditions or surgical conditions. Considering the amount of salt in food today, I very strongly recommend that they try to limit their salt consumption. Again, as a nephrologist, I think about the hypertension and renal disease sides as well. I also make recommendations regarding protein intake and perhaps oxalate intake depending on the type of stone and type of patient.
Looking at dietary modifications versus medication, what do you think patients want more?
Unfortunately, patients are very inclined to want medication because it’s much easier to take a pill than make the effort and the conscious change in dietary habits. It is usually time consuming when I see patients because I’m trying to change lifestyles more than anything else, and it’s very difficult. Even foods that are regarded as healthy may actually be harmful in terms of kidney stones. The epidemiology of stone disease has changed so much in our country, and it’s probably because of many changes in our dietary habits.
Who should be managing the follow-up for recurrent stone patients?
I think these patients should be managed with a multidisciplinary approach. A dietitian or nutritionist could be involved with them. The nephrologist and primary care physician could play a big role as well in the prevention of kidney stone disease. And ultimately, there is the urologist. You guys see these patients much more commonly than any of us. For the most part, urologists have very good knowledge of how to handle stone attacks and can play a very important role in the management of stone prevention. In terms of work force, there are more urologists than nephrologists in the community, and urologists could probably manage those patients in the long term, making a lot of emphasis on the changes mentioned above and management of medications as well. But in an ideal world, it would be a combination of providers managing these patients.
What’s your advice for a young urologist who wants to become an expert in stone prevention and minimizing stone recurrence?
I would tell them to think of it as more of a chronic disease than the way that we used to think about it. I would advise them to insist more to patients in terms of dietary and lifestyle modifications. Most of the medications haven’t changed in a long time, so it’s very easy to get a handle on those. I would also recommend that they not forget about kidney function, because even though a kidney stone is not the biggest risk factor for chronic kidney disease or end-stage renal disease, it could affect these conditions, and it definitely affects the quality of life of those patients.