A new study has found that family doctors in two U.S. states don’t order as many screening tests for cancer for patients they see later in the day.

And then those later-day patients are less likely to actually get the screening tests done than people who visit their doctors earlier in the day.

Researchers at the University of Pennsylvania believe the decline in screening rates may in part be due to “decision fatigue” and doctors falling behind as the day progresses. They suggest an electronic “nudge” built in to health records could improve test rates.

Researchers from the Perelman School of Medicine and the Wharton School published their results Friday in the JAMA Network Open, a monthly open access medical journal published by the American Medical Association.

"Our findings suggest that future interventions targeting improvements in cancer screening might focus on time of day as an important factor in influencing behaviours," said the study's lead author, Esther Hsiang, a Wharton business student and researcher with the Penn Medicine Nudge Unit.

"We believe that the downward trend of ordering may be the result of 'decision fatigue,' where people may be less inclined to consider a new decision after they've been making them all day. It may also stem from overloaded clinicians getting behind as the day progresses."

The Penn Medicine Nudge Unit says “it is the world’s first behavioral design team embedded within a health system.  Our mission is to leverage insights from behavioral economics and psychology to design and test approaches to steer medical decision-making toward higher value and improved patient outcomes.”

The researchers found that primary care doctors ordered breast cancer screening among eligible patients most often for those seen in the 8 a.m. hour at 64 per cent. That compared to 48 per cent among patients with appointments at 5 p.m.

The results were similar for colon cancer screening. Tests were ordered for 37 per cent of 8 a.m. patients, compared to 23 per cent of those coming in later in the day.

The research covers data from 2014 to 2016 across 33 primary care practices in Pennsylvania and New Jersey.

The authors also tracked approximately 19,000 patients at these practices who were eligible for breast cancer screening and 33,000 for colorectal cancer to see whether they completed a screening within a year of seeing their family doctor.

They found that breast cancer screenings, including mammograms, were completed for 33 per cent of patients seen by their family doctor in the 8 a.m. hour. But just 18 per cent of those seen at 5 p.m. or later got the screening done.

For colorectal cancer, screenings such colonoscopies, sigmoidoscopies, and fecal occult blood tests were done by 28 per cent of patients seen at the beginning of the day, dropping to 18 per cent for those seen at the end of the day.

Researchers also found there was a brief spike in screening orders for breast and colon cancers when patients saw their clinician around noon. The rates fell as the afternoon wore on. This trend held true for one-year completion rates, as well. The study team suggests “this may be due to lunch breaks that give clinicians an opportunity to catch up and start fresh,” according to a press release from the University of Pennsylvania School of Medicine.

These cancer tests results mirror a 2018 study examining rates of flu vaccinations by time of appointment.

In that study, an electronic "nudge" was built into the system that prompted doctors to accept or decline an influenza vaccine order, which helped spur an increase of vaccinations by nearly 20 per cent, as compared to patients with doctors who weren't nudged.

"Our new study adds to the growing evidence that time of day and decision fatigue impacts patient care," said Dr. Mitesh Patel, director of the Penn Medicine Nudge Unit and an assistant professor of medicine.

"In past work, we've found that nudges in the electronic health record can be used to address these types of gaps in care, which we suspect will be the case here. Future research could evaluate how nudges may be implemented in order to improve cancer screening."