Armed with a big federal grant, Penn Medicine and Children's Hospital of Philadelphia (CHOP) are teaming up to prevent kidney stones, an excruciatingly painful condition that is increasing in both adults and children.
Along with three other institutions, they'll be part of a clinical trial testing whether a $55 "smart" water bottle that sends data on how much users drink to a phone app, plus financial incentives, can keep people of all ages who've had one kidney stone from getting another one.
"The goal of this grant is to look at kidney stones as a disease that can occur over a lifetime," said Greg Tasian, a pediatric urologist and epidemiologist at CHOP who will co-lead the local effort. "It's the same disease that's happening at different ages."
About one in 11 Americans has had a kidney stone, 70 percent more than 15 years ago. Kidney stones are pebble-like structures that form in the kidneys and can cause severe pain if they block urine flow. The condition was once primarily a problem for white, middle-aged men, but numbers have been growing in recent years among women, young people, and African Americans, Tasian said.
Kidney stones once were extremely rare in children, but are now common enough that CHOP established a Pediatric Kidney Stone Center. The numbers have doubled since 1997, but are still low, especially compared with adults. Among boys ages 15 to 19, about 100 per 100,000 get a kidney stone in a year. For girls in that age range, the risk rises to 140 to 150 per 100,000. "It's truly a new problem within pediatric medicine," Tasian said.
Treatment for kidney stones costs an estimated $10 billion each year, according to the National Institutes of Diabetes and Digestive and Kidney Diseases. People who've had one have a 39 percent chance of having another within 15 years. Doctors still don't know what causes them or why they're increasing, Tasian said.
One theory: warmer temperatures due to climate change could be increasing dehydration. A link with obesity has also been suggested, as has lack of calcium in the diet. Tasian is also looking at the microbiome and antibiotic exposure.
A 1996 trial in Italy, however, found that drinking a lot of fluids reduced recurrence by 50 percent.
The new study will enroll more than 1,600 people ages 12 and older at Penn, CHOP, University of Texas Southwestern Medical Center of Dallas, University of Washington in Seattle, and Washington University in St. Louis. Penn and CHOP will share a five-year grant from the National Institutes of Health's Urinary Stone Disease Research Network that will give them $450,000 a year.
The goal is to get people who've had kidney stones to drink more so they will urinate more. While many know they should, they often have difficulty actually doing it. On average, study participants are expected to produce 2.5 liters of urine a day, about 10.5 cups. How much they'll have to drink to produce that much urine will vary depending on whether they sit in a comfortable office all day or work outside in hot weather, but it will be a lot. Peter Reese, a nephrologist and epidemiologist at Penn Medicine and the other local project leader said it is "common to have to drink 2 1/2 to 3 liters in order to pee out two." A liter is about a quart.
Study participants will get 24-ounce water bottles made by Hidrate Spark that use Bluetooth to report how much they're drinking to their smart phones — and study leaders. (They won't have to measure urine.) Participants will get $1.50 a day if they meet their drinking goals. If they don't, they'll get individual coaching to help break down barriers to drinking more. Some people, Tasian and Reese said, simply don't like the way it feels to drink a lot. Others may have concerns about access to safe bathrooms or about needing frequent breaks from work or school.
Reese said he is especially excited about the potential of wireless devices to help people form new habits. In the old days, a doctor might suggest a change, then wait six months to see if the patient did anything. Smart devices make it possible for investigators to monitor behavior immediately and intervene much more quickly.
"It's a very exciting time to work in the field of health-behavior change," he said. "I'm really optimistic about what the next 10 years will bring."