Paediatric Appendicitis Risk Calculator

Journal Club Summary 21/03/2019

Today we talked about paediatric appendicitis scores, appendicitis scores and clinical decision scores and rules in general.

The article we looked at was Development and Validation of a Novel Paediatric Appendicitis Risk Calculator (pARC) Kharbanda AB, Vazquez-Benitez G, Ballard DW, et al. PEDIATRICS. 2018 Apr;141(4):e20172699.  (if you would like a copy please let me know.)

In summary, this study developed a Paediatric Appendicitis Risk Calculator (pARC) using clinical findings in a cohort of normally well children presenting to ED with abdominal pain and then validated it using a separate cohort of patients, as well as comparing it to the existing Paediatric Appendicitis Score. The conclusions we reached from our discussion of the article were:

• The description of the methodology was confusing and we did not feel we would be able to replicate it based on what was described in the article (one of the “acid tests” for an article.)

• The article did not tell us what the components of the calculator they derived actually were! This is probably the biggest frustration with this article. It states: “The pARC is not intuitive and requires sophisticated calculations… The pARC can be easily programmed and integrated within the electronic health record.” Not terribly useful to staff outside of the hospitals the author plans to implement his calculator in!

We entered into some interesting discussion around clinical decision rules, summarized below:

• Most clinical decision rules (think PECARN/CHALICE/HEART…. almost anything) condense findings on history and examination that we would all obtain during a routine assessment into a list and allocate a quantitative value to the presence or absence of those findings.
• Most clinical decision rules are too hard to remember in full. Yes you can plug them into an app but still….
• We usually know who has appendicitis (or a severe head injury, or ischaemic chest pain) after performing an adequate clinical assessment.
• Possibly more importantly, we usually know who doesn’t have these conditions after assessing them.
• The difficult patients are:
  • The “maybes” ie the intermediate scoring patients
    • Many clinical decision rules are NOT useful for this intermediate group of patients.
• So if clinical decision rules confirm what we already know and don’t help us when we don’t know, do they have any use at all?
  • Potentially.
    • They are sometimes helpful to convey information to other teams
      • Eg convincing the surgeon they have appendicitis because they score highly on the Alvarado/PAS score
    • They can be useful in rationalizing imaging and investigations
      • Eg deciding NOT to image low risk patients (and in some cases, eg high risk appendicitis patients if admission & OT is more appropriate)
  • They can be useful for developing a standardised guideline for conditions in which there is a large variation in practice within and between departments (ie calculate score then admit/investigate/discharge based on score)
• They can be useful in reassuring ourselves when our gut feeling is “this is not appendicitis” that a patient is, in fact, low risk and ok to go home!

Any other thoughts on these issues or suggestions for Journal Club articles, please let me know.