Exploring the Clinical Journey of Children With Primary Hyperoxaluria

Exploring the Clinical Journey of Children With Primary Hyperoxaluria 150 150 JoAnna Pendergrass, DVM

Children with primary hyperoxaluria, a rare genetic disease, navigate a complicated clinical journey that includes a heavy reliance on health care services and usage of multidisciplinary care.

Primary hyperoxaluria (PH) is a rare disease caused by genetic mutations of enzymes that regulate hepatic glyoxylate metabolism, leading to oxalate overproduction. The excess oxalate is excreted by the kidneys, eventually damaging the kidneys and causing such renal problems as kidney stones and nephrocalcinosis.

The three types of PH — PH1, PH2 and PH3 — differ according to enzymatic mutation.

Renal damage is the most common consequence of PH, but other body systems, including the cardiovascular and endocrine systems, can also be affected.

Limited information is available about the management and evaluation of pediatric PH and the lived experience of children with the disease.

Christina Ching, MD, a pediatric urologist at Nationwide Children’s Hospital, was part of a multi-institutional effort to conducted a retrospective study illustrating the clinical journey of children with PH in the United States.

“The real-world experience of caring for children with PH is that they rely heavily on health care resources, yet could benefit from more multidisciplinary care,” says Dr. Ching.

Study results were published in the European Journal of Pediatrics.

Using a timeframe of January 2009 and January 2021, this multi-institutional collaboration selected a cohort of 33 patients aged < 18 years from the PEDSnet database. PEDSnet is a clinical research network of seven children’s hospitals in the United States, including Nationwide Children’s.

The following data were collected from patients’ electronic health records:

  • eGFR
  • Diagnostic testing and imaging
  • Hospital support utilization
  • Medical and surgical treatment interventions
  • Time between clinical outcomes and diagnosis

The researchers defined the time of PH diagnosis as the cohort entrance date (CED).

Most patients were non-Hispanic White (73%) and had PH1 (70%). The median age at CED was five years.

The patients relied heavily on health care. For example, 82% of the patients underwent imaging to evaluate kidney stone formation. About half (54%) of the patients went to the emergency department at least once, and 46% were admitted to the hospital.

Nearly half of the patients (46%) underwent kidney stone surgery, while 12% received dialysis or a renal transplant.

Nephrology was the most used specialty care within the study cohort (97% of patients), and urology was the second-most used specialty (67% of patients).

However, specialties were generally underused within the cohort.

“We can encourage more specialty involvement in several ways: conducting studies to improve our understanding of rare natural diseases like PH, identifying how these diseases affect other body systems, and sharing this information among the specialties,” says Dr. Ching.

Many patients in the study received treatment interventions before their PH diagnosis. The researchers noted that a delayed diagnosis can be attributed to the disease’s rarity and lack of provider familiarity with the disease.

Dr. Ching explains that a delayed diagnosis adversely affects renal health and other organ systems. An earlier diagnosis could improve patients’ clinical outcomes, particularly with new therapies like RNA interference, and reduce health care utilization.

This multi-institutional group will continue identifying clinical characteristics of PH to facilitate a better diagnosis of PH1 in children with kidney stones. “We hope to provide clinicians with strategies to increase their index of suspicion for PH,” she adds.



Ching CB, Dickinson K, Karafilidis J, Marchesani N, Mucha L, Antunes N, Razzaghi H, Utidjian L, Yonekawa K, Coplen DE, Muneeruddin S, DeFoor W, Rove KO, Forrest CB, Tasian GE. The real world experience of pediatric primary hyperoxaluria patients in the PEDSnet clinical research network. Eur J Pediatr. 2023 Jul 1. doi: 10.1007/s00431-023-05077-y.

About the author

JoAnna Pendergrass, DVM, is a veterinarian and freelance medical writer in Atlanta, GA. She received her veterinary degree from the Virginia-Maryland College of Veterinary Medicine and completed a 2-year postdoctoral research fellowship at Emory University’s Yerkes Primate Research Center before beginning her career as a medical writer.

As a freelance medical writer, Dr. Pendergrass focuses on pet owner education and health journalism. She is a member of the American Medical Writers Association and has served as secretary and president of AMWA’s Southeast chapter.

In her spare time, Dr. Pendergrass enjoys baking, running, and playing the viola in a local community orchestra.