Date: October 22nd, 2019

Reference: Iyengar R et al. The Effect of Financial Incentives on Patient Decisions to Undergo Low-value Head Computed Tomography Scans. AEM October 2019.

Guest Skeptic: Dr. Justin Morgenstern is an emergency physician and the creator of the excellent #FOAMed project called First10EM.com

Case: A 21-year-old comes into the emergency department after being knocked unconscious while playing rugby. The patient is now feeling great, or as they say in New Zealand “sweet as”. He had no pain, nausea, or neurologic symptoms. His exam is normal. You aren’t worried, but his dad is the coach of the American national rugby team and says that his players always get a CT when this happens. You wonder what factors might influence a patient’s preference for imaging?

Background: The CT scan is arguably one of the most important pieces of diagnostic technology that we use in emergency medicine. It allows for incredibly rapid identification of a myriad of life-threatening conditions.

However, likely because it is such a valuable tool, there seems to be little doubt that we overuse it. For example, one study that looked retrospectively at all head CTs ordered for trauma concluded that more than 1/3 were unnecessary based on the Canadian CT head rule [1].

Not only does unnecessary testing reduce efficiency and add costs, it also directly harms patients with unnecessary radiation [2]. Many imaging decisions are obvious – the patient either clearly requires or clearly does not require imaging.

One way to decrease CT scans of the head is to use a clinical decision instrument like the Canadian CT Head Rule (CCHR). The SGEM covered the classic paper on the CCHR by the Legend of Emergency Medicine Dr. Ian Stiell on SGEM#106.

We also recently reviewed a paper that looked at increasing the CCHR age criteria from 65 years of age to 75 years of age (SGEM#266). The bottom line was that this paper opens the door for further research to try to narrow the criteria in the CCHR to further reduce unnecessary head CT imaging in the emergency department. However, further, high quality prospective studies are required prior to clinical application.

There is a great deal of uncertainty in emergency medicine, which leaves a sizeable number of patients in a grey zone – where harms and benefits are closely matched, qualitatively different, or just unknown. For these patients, shared decision making is probably the best route forward.

Even when it seems clear to the physician that imaging isn’t required, we can be met with resistance from our patients. In addition, if we are working in a zero-miss culture, we may be more likely to order CT scans that are not medically necessary. Thus, it is important to know what factors influence patients’ decision to undergo CT.

This study by Iyengar and colleagues examines the impacts of financial incentives, as well as varying levels of risk and benefit, on patient preference for CT imaging in the setting of low risk head injury [3].

Clinical Question: Do financial incentives, together with potential risk and potential benefit information, influence patient preference for diagnostic testing?

Reference: Iyengar R et al. The Effect of Financial Incentives on Patient Decisions to Undergo Low-value Head Computed Tomography Scans. AEM October 2019.