Yesterday, I wrote about the usual reasons for delayed diagnosis: insufficient diagnostic technique or insufficient recognition. What about time of day? A recent paper looked at the correlation between admission time and rate of missed injuries.

The work was done at a large teaching hospital and Level I trauma center in Australia. A large number of patients were reviewed over an 11 year period. The study was complicated slightly by the implementation of a dedicated trauma unit in the middle of the study period, but the authors stratified their groups to account for this. 

Results were stratified by time of admission: office hours vs after-hours vs weekends. Missed injuries were defined as those found after completion of the primary and secondary surveys. The overall statistical treatment appeared to be robust.

Here are the factoids:

• A huge number of patients (53,000) were reviewed. This is a busy place!
• There were 2519 missed injuries in 1262 patients (2.4%) [low!]
• Missed injuries occurred during office hour admissions in 2.2%, after-hours in 2.6%, and on weekends 2.5% of the time
• The increased incidence of delayed diagnosis in after-hours admits was marginally significant (p = 0.048)
• Missed injuries appeared to have increased over time, and were 1.34 times more likely at the end of the study period vs the beginning
• Thoracic spine and abdominal injuries were most the commonly missed

Bottom line: Hmm, time of day was not in my list of reasons for missing diagnoses. What gives? If you read the article closely, the trauma service at this hospital was staffed with a higher number of trainees after hours and on weekends than during office hours. It was also noted that incomplete physical examination was thought to be a factor in many of the delays. Most likely, both of my listed reasons were in play here. Inexperienced clinicians and insufficient examination are both major factors. And what about the increase in missed injuries over time? Midway through the study, the hospital implemented a dedicated trauma unit, and a tertiary exam became routine. This identified more injuries after the primary and secondary surveys were complete. 

Tomorrow I’ll talk about strategies to drop the incidence of missed injury.

Reference: Office hours vs after-hours: do presentation times affect the rate of missed injuries in trauma patients? Injury 2015, in press.