Research In Practice Blog

OASIS Kidney
CHOP Awarded PCORI Funding to Investigate Optimal Strategy for Managing Asymptomatic Kidney Stones
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By Lindsey Klinger-O'Donnell

Children’s Hospital of Philadelphia (CHOP) has been approved for $17 million in research funding from the Patient-Centered Outcomes Research Institute (PCORI), to lead a groundbreaking pragmatic trial evaluating management strategies for asymptomatic, non-obstructive kidney stones. The focus of the project will be to determine whether observation or upfront surgery results in less life disruption from asymptomatic kidney stones for children and adults. Researchers will conduct the trial across 30 sites in PCORnet using patient data from over 1,300 patients aged 6 years and older with asymptomatic, non-obstructive kidney stones measuring 4 to 10 mm at 30 health systems in the U.S. 

CHOP will serve as the data coordinating center for the trial with CHOP pediatric urologist Gregory Tasian, MD, MSc, MSCE, and urologist Ryan Hsi, MD, a urologist at University of California-Irvine, co-leading the study. Dr. Tasian is Professor of Surgery and Epidemiology, director for the Center for Outcomes Research in Surgery (CORES), and Co-Associate Director for Clinical Trials at Clinical Futures, a CHOP Research Institute Center of Emphasis. Dr. Tasian and his collaborators are evaluating whether observation, compared with upfront surgery, results in less healthcare-related disruption among children and adults with asymptomatic kidney stones. The study will also identify which groups benefit most from each strategy and the preferences and values that inform the choice between observation and upfront surgery.

For years, Dr. Tasian has been leading efforts at CHOP to improve the health of children and adolescents with early-onset kidney stone disease through randomized trials, prospective observational studies, and large data analytics.  

Building the Evidence Base for Kidney Stone Research 
Kidney stone disease is a disorder of mineral metabolism that affects approximately 11% of the population in the United States and results in annual healthcare costs exceeding $10 billion. It can impact individuals of all ages—from childhood to older adulthood—and includes both those who are otherwise healthy and those with complex medical conditions. Individuals with asymptomatic kidney stones may experience pain and disruptions in their lives when stones move and obstruct the kidney or when they undergo surgery to remove them. These disruptions, which can include emergency department visits, hospitalizations, and unplanned surgeries, may lead to short-term disability, financial strain, and a decline in physical, emotional, and social health.

A critical barrier to improving the health of the roughly 40 million Americans with kidney stone disease is the weak evidence guiding management of individuals with asymptomatic kidney stones. The main management options are:

  1. Observation - the surveillance of asymptomatic stones with periodic CT, ultrasound, or x-ray, and clinic visits.
  2. Upfront surgical removal - the planned removal of asymptomatic stones. Patients randomized to upfront surgery could choose between ureteroscopy and shockwave lithotripsy.

Both options are safe, part of usual care, widely accessible, and covered by all types of insurance.  Experts in the medical community disagree about the relative merits of observation and upfront surgery, highlighting the clinical equipoise for these alternatives. 

The Observational Approach versus Surgical Intervention for Stones (OASIS) trial would create a new paradigm of informed decision-making for perhaps the most common scenario in the management of patients with kidney stones by determining whether observation or surgery results in less life disruption and which patients, such as those that have new stones or those that have residual stones after surgery, have greater benefit.

Trial Methodology
As a disease that occurs across the lifespan, the trial will include individuals ≥6 years of age with asymptomatic, non-obstructive kidney stones between 4 to 10 mm who receive care at 30 medical centers that participate in a PCORnet clinical research network. 

The OASIS trial is built around three main aims:

  1. Comparing Life Disruption
    The first objective is to find out whether observation leads to less life disruption compared to immediate surgery. The trial will have enough power (90%) to detect a 40% difference in stone-related ED visits, hospitalization, and unplanned surgery for symptoms over a two-year follow-up, a difference that patients and caregivers stated would change their decision for selecting a management strategy. They anticipate that patients who choose observation will experience fewer healthcare visits and interventions related to their kidney stones.
     
  2. Understanding Variability in Treatment Effects 
    The second goal delves into how the benefits of either observation or upfront surgery may vary among different patient groups. For instance, some individuals might benefit more from observation than others, based on factors like age, medical history, or the characteristics of their kidney stones. By analyzing this “heterogeneity of treatment effect,” researchers hope to uncover tailored approaches for different patient profiles, ultimately leading to more personalized care.
     
  3. Exploring Patient Preferences
    Finally, the trial will focus on patient preferences. By enrolling 300 participants who want to participate but decline randomizations, the researchers aim to understand the preferences and values that inform their treatment choices. They’ll conduct in-depth interviews with a select group to capture the nuances of how individual characteristics and life circumstances play into decisions around observation versus surgery.
    As the OASIS trial progresses, researchers will gain valuable insights into how different treatment strategies can impact both health outcomes and the everyday lives of individuals living with kidney stones. By understanding patients' preferences and examining how each treatment affects their experiences, they may soon be able to redefine the standard approach to managing patients of all age's asymptomatic kidney stones. 

“Our study is the largest randomized trial ever conducted to address this research question, and it is the only one that includes both children and adults. The results will not only inform guideline development and surgical care practices but will also lead to improved clinical outcomes and patient experiences for both children and adults with kidney stone disease,” stated Dr. Gregory Tasian, Principal Investigator of the study.


Dr. Tasian emphasized that “The study design is also unique because it centers on patient choice. This will provide us with valuable insights into the decision-making processes of patients. Consequently, researchers and clinicians will be better equipped to guide patients' thought processes while empowering them and their caregivers with knowledge that will help them make more informed treatment decisions. We believe this will ultimately enhance their health. Our aim is to build trust with patients and caregivers while educating them to make better-informed choices regarding their health and the health of their loved ones.”

Partnering with Families and Patients to Improve Outcomes and Guide Decision-Making
A key component of the trial is that it will capture additional outcomes that patients consider meaningful. These secondary outcomes include anxiety, how pain affects daily life, overall quality of life, experiences with passing kidney stones, and the number of school and workdays missed due to kidney stones. Up to 100 participants will be interviewed to gain insight into the personal preferences and values that guided their choice between observation and immediate surgery. 

“Patients with kidney stones and their family members proposed the OASIS trial and selected the outcomes to be measured. Patients and caregivers will be actively involved in all phases of the OASIS trial, including approving key documents, interpreting the results, and co-authoring communications that report the trial findings,” said Dr. Tasian. 

Partners and Collaborators
This study builds upon years of patient-centered research conducted by Dr. Tasian. The Kidney Stone Engagement Core will ensure that patients and caregivers remain at the center of the trial and are involved in key decisions. all participating sites share a common data model for electronic health record (EHR) data. Along with CHOP and Vanderbilt University Medical Center, who will serve as the clinical coordinating center participating sites include: Children’s Hospital of Wisconsin; Cincinnati Children’s Hospital Medical Center; Lurie Children’s Hospital; University of Pennsylvania; Nationwide Children’s Hospital; Children’s Hospital Colorado; Children’s National; University of Florida; Oregon Health & Science University; University of Washington Urology; Intermountain Medical Center; University of Texas Southwestern; University of California, San Francisco; Columbia University Medical Center; University of Alabama at Birmingham; University of Michigan; Montefiore/Albert Einstein College of Medicine; Riley Children’s Hospital/Indiana University; Primary Children’s Hospital/University of Utah; Temple University Health System; Rush University Medical Center; Medical College of Wisconsin; Duke University Urology; University of North Carolina; Stanford Research Repository; Stanford Children’s Health; and Mayo Clinic (Rochester and Arizona). 

To expand the impact of the trial and facilitate implementation of results into real-world clinical care, researchers will leverage the existing relationships of the investigators with urologists in the U.S. and around the world. Additionally, researchers will engage directly with other established networks to disseminate and implement the results of the OASIS trial. These networks include the PKIDS Care Improvement Network, USDHub, NASQOL-C, and the Kidney Stone Collaborative. Researchers will also share results with professional organizations such as the American Urological Association, the ROCK Society, and the Endourological Society.

Funding for this study has been approved by the Patient-Centered Outcomes Research Institute (PCORI) pending completion of PCORI’s business and programmatic review and issuance of a formal award contract. PCORI, an independent nonprofit organization, is the leading funder of patient-centered comparative clinical effectiveness research in the United States.

For more information, read this CHOP News Brief and this CHOP Research Institute Cornerstone Blog post. Also, please visit PCORI’s website for the full project summary. 

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