Gulp. We’ve all heard that drinking more water is a healthy habit, but taking steps to consistently increase fluid intake can be difficult to swallow. It’s especially challenging for children because, while the Institute of Medicine has guidelines for adequate intake of water, there are no specific recommendations for how much fluid they ideally should drink to avoid long-term medical problems such as kidney stone formation.
Researchers at Children’s Hospital of Philadelphia are thirsty for answers. They will be participating in a new Urinary Stone Disease Research Network (USDRN), a collaboration with the University of Pennsylvania, the University of Washington, Washington University in St. Louis, University of Texas Southwestern Medical Center, and Duke University that is supported by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).
The USDRN will perform the largest studies on urinary stone disease that include pediatric and adult patients to date, and it has opened the Prevention of Urinary Stones with Hydration study (PUSH), a two-year randomized trial of a strategy to maintain high fluid intake to decrease stone recurrence among adolescents and adults. The study leaders at the CHOP-Penn Medicine site are principal investigators Gregory E. Tasian, MD, MSc, MSCE, a pediatric urologist and epidemiologist at CHOP; and Peter Reese, MD, MSCE, a nephrologist and epidemiologist at the Perelman School of Medicine at the University of Pennsylvania. They also are senior scholars with Penn’s Center for Clinical Epidemiology and Biostatistics.
“As the largest children’s hospital in the USDRN, CHOP and the Pediatric Kidney Stone Center will contribute substantially to this effort,” Dr. Tasian said. “CHOP has long been a leader in advancing healthcare for children with rare and common diseases. CHOP’s participation in the USDRN will allow us to be at the forefront of decreasing the morbidity of urinary stone disease, which now often begins during childhood.”
While drinking more fluids is a safe and simple intervention that is generally recommended for stone-forming patients, convincing them to make it a priority and then following their adherence is not so easy. A unique way that Dr. Tasian hopes to accomplish this in the USDRN’s studies is to incorporate behavioral economics, such as financial incentives, to encourage healthy behavior in combination with mobile health technology to track it.
The PUSH study team plans to enroll 1,642 people 12 years of age or older who have had at least one symptomatic stone in the past three years. They will randomize study participants into an intervention group and a control group. Both groups will receive a wireless-enabled water bottle that allows for real-time feedback on how well they’re meeting personalized fluid goals. Similar to a step activity counter that shows how much you’re moving each day, the water bottle synchronizes via Bluetooth technology with a smartphone app to gauge your fluid intake.
“The water bottle allows for personalized medicine and is an innovative research tool that has a lot of potential,” Dr. Tasian said. “Based on how much additional fluid a patient needs to drink to make enough urine to decrease stone recurrence, you can set the fluid consumption goal, program it into the phone, and track it over time.”
Participants in the intervention group also will be given financial incentives if they achieve their fluid targets, and they will meet with a health coach to identify and overcome barriers to drinking more liquids, such as lack of access to fluids at work and school. The study team anticipates that people will be more motivated by tangible, short-term rewards to change their behavior, especially since the benefits of fluid intake are not immediately apparent because symptoms of kidney stone recurrence may not appear for months or years.
The prevalence of kidney stones disease has nearly doubled in the last 15 years in both adults and children, affecting about one out of 11 Americans, according to the NIDDK. It also is the most expensive non-malignant urologic condition in the US, costing about $10 billion annually. About 10 percent of visits to the emergency department for kidney stones are for repeat encounters.
Acute symptomatic episodes of kidney stones can be extremely painful. A higher concentration of calcium and other minerals in the urine, which can be exacerbated by low fluid intake, promotes the formation of kidney stones over time. When the stones detach from the kidney, they can end up trapped within the ureter and block the outflow of urine from the kidney to the bladder.
Until they endure such an excruciating experience, people often don’t recognize the importance of taking measures to reduce their risk of kidney stones, such as remembering to maintain access to fluids and to drink them, particularly during periods of heat or exertion. In previous epidemiological research published in Environmental Health Perspectives, Dr. Tasian and colleagues suggest that rising temperatures due to climate change could offer a possible explanation for why kidney stones may increase in the future for individuals who are predisposed to the condition.
Another recent study published in The Clinical Journal of The American Society of Nephrology described the increasing incidence of kidney stones among children and adults living in South Carolina. Among age groups, the greatest increase was observed among 15 to 19 year olds, in whom incidence increased 26 percent per five years, which illustrates the need for randomized controlled trials of urinary stone disease that include youth, such as those that the USDRN is planning.
Once a kidney stone episode gets a family’s attention and they are under the care of CHOP’s Pediatric Kidney Stone Center, Dr. Tasian focuses on educating them about preventing it from happening again. About half of patients who are diagnosed with a kidney stone will have a recurrence within five to 10 years.
“Kidney stones are a disease that can occur at any age, and what we’re seeing is that it now has a much, much earlier age of onset,” Dr. Tasian said. “My primary research focus is on secondary prevention. It is incredibly important to develop interventions and strategies to change behaviors and develop habits that reduce kidney stone risk and improve health over the lifetime.”
In addition to fluid intake investigations, the USDRN’s network will pursue other research objectives to provide evidence for management approaches to kidney stone disease, including reducing pain from ureteral stents, and establishing a repository of urine and blood samples from patients with kidney stone disease to support future research.