A risk calculator may help safely avoid unnecessary CT scans in children 5 and older
By Janet Byron
Using a simple new risk calculator, Kaiser Permanente emergency doctors were able to accurately gauge the risk of appendicitis in children, according to a new study published today in Annals of Emergency Medicine.
In the study, “Validation of the pediatric Appendicitis Risk Calculator (pARC) in a Community Emergency Department Setting,” the tool was validated in 11 Kaiser Permanente Northern California community emergency departments between October 2016 and April 2018.
“Using the doctor’s exam, the patient’s medical history, and a single blood test, the pARC successfully predicted appendicitis risk from very low to high, and it did so better than previously studied tools,” said lead author Dale Cotton, MD, senior emergency physician at Kaiser Permanente’s South Sacramento Medical Center.
A difficult diagnosis
Appendicitis — an inflammation of the appendix, which may cause abdominal pain and other symptoms such as vomiting — can be life-threatening if not treated promptly. Appendicitis is especially difficult for emergency physicians to diagnose in children, because children may not be able to communicate their symptoms effectively.
Erring on the side of caution, emergency physicians tend to order CT scans to evaluate appendicitis in children, “but research shows that we weren’t necessarily catching more appendicitis,” Dr. Cotton said. “CT scans are costly and expose children to ionizing radiation that can increase the risk of cancer. At the same time, emergency physicians do not want to miss an important diagnosis like appendicitis.”
The pARC tool was developed by Elyse O. Kharbanda, MD, and colleagues at the HealthPartners Institute, and Anupam Kharbanda, MD, at Children’s Minnesota, with the participation of researchers from Kaiser Permanente’s Clinical Research on Emergency Services and Treatments (CREST) Network.
Using data from pediatric patients, the researchers developed an algorithm for predicting the risk of appendicitis based on sex, age, absolute neutrophil count (a blood test), the duration of pain, migration of pain to the right lower abdomen, “guarding” of that area, and the most tender location during the physical exam.
Validating the risk calculator
The pARC tool accurately predicted acute appendicitis risk in 2,089 patients between 5 and 20 years old enrolled in the trial. Investigators compared the pARC with the previously best-performing tool, and found that it performed better. The pARC classified 54% of patients as low or very low risk (less than 15% risk of appendicitis), 43% as intermediate risk (between 15% and 84% risk of appendicitis), and 4 percent as high risk (an 85% or greater chance of having appendicitis).
“For the pARC to be a useful tool in general practice, it had to perform well in the emergency departments of community hospitals that care for patients of all ages,” said co-author David R. Vinson, MD, senior emergency physician in Kaiser Permanente’s Sacramento Medical Center and adjunct researcher with the Kaiser Permanente Northern California Division of Research.
“And it did just that. The pARC can help assist in the diagnosis of appendicitis in general EDs where children are more often brought for care.”
“Significant improvement over existing methods”
Drs. Kharbanda and Kharbanda, co-authors of the current study, are leading ongoing studies to evaluate the impacts of the pARC on clinical care.
“Studies such as Dr. Cotton’s show how pARC is a significant improvement over existing methods of identifying appendicitis risk in pediatric patients,” Dr. Elyse Kharbanda said. “While we’ll continue to explore the benefits and uses of the calculator, I hope this new data will make providers more confident in using it to help patients.”
The pARC tool continues to be studied in Kaiser Permanente emergency departments across Northern California to show if it can improve the decision to order an imaging test. It will soon be widely available for emergency medicine providers who want to integrate it into their clinical practice.
“PARC allows us to more quantitatively discuss what a child’s risk of appendicitis is when deciding on the next step,” Dr. Cotton said. “This is especially helpful when we find that a child is at low risk. We can confidently say, ‘I don’t think further testing will be helpful.’”
The study was funded by the National Institutes of Health.
In addition to Cotton, Vinson, E. Kharbanda, and A. Kharbanda, co-authors of the study included senior author Dustin W. Ballard of Kaiser San Rafael and the Division of Research, as well as E. Margaret Warton, MPH, Uli K. Chettipally, MD, MPH, Mamata V. Kene, MD, MPH, James S. Lin, MD, Dustin G. Mark, MD, Dana R. Sax, MD, MPH, Ian D. McLachlan, MD, MPH, Adina S. Rauchwerger, MPH, Laura E. Simon, BA, all of Kaiser Permanente; and Gabriela Vazquez-Benitez, PhD, of Health Partners Institute, Bloomington, MN.