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CARE Consortium: Return to play and risk of repeat concussion in football

Duration between injury and return to play has risen sharply

Sport-related concussion has generated heightened interest among the public and researchers alike during the past two decades, but has clinical management of the injury changed accordingly?

A new study from the NCAA-U.S. Department of Defense Concussion Assessment, Research and Education Consortium suggests that it has — at least among college football players.

Michael McCrea, professor of neurosurgery and co-director of the Center for Neurotrauma Research at the Medical College of Wisconsin, led a team of researchers who compared data relevant to concussion management and repeat concussions from the ongoing CARE Consortium study with that of the original NCAA Concussion Study, which gathered data from 1999 to 2001. Both studies involved college football players from all three NCAA divisions. In all, 184 concussions were evaluated exclusively in football student-athletes in the older study, while 701 football student-athletes from a larger group encompassing 23 other sports were included from CARE from a period spanning 2014-17, thereby allowing a direct comparison of football student-athletes in these studies.

The differences between the studies’ results were striking, as articulated in a recent paper published in the British Journal of Sports Medicine.

What did the study find?

The average time between injury and return to play in the original NCAA Concussion Study was 6.7 days. In the CARE study, that figure increased to 16.1 days.

Differences also existed in the symptom-free waiting period (the interval between when student-athletes became symptom-free and when they were cleared for unrestricted return to play). In the original study, student-athletes were withheld from play for 3.3 days after symptoms lifted, on average. The concussed student-athletes in CARE had an average 7.3-day symptom-free waiting period.

Additionally, the rate of same-season repeat concussion in the CARE study was 41% lower  than in the earlier NCAA Concussion Study. Further, among those who suffered a repeat concussion, the average interval between injuries in CARE was 50.8 days longer. Among 701 concussed CARE student-athletes, there was only one repeat concussion within 10 days of the initial injury, which accounted for only 3.7% of all repeat concussions. Comparatively, in the older NCAA Concussion Study, 91.7% of all repeat concussions occurred within 10 days of the first injury.

What are the implications?

The stark differences between these study results point to “a major shift in approaches to clinical management of sport-related concussion in NCAA collegiate football players over the past 15 years,” McCrea and his co-authors wrote.

Recent recovery times that measured longer and symptom-free waiting periods before return to play were a near-universal aspect of concussion management. The longer period away from the exposure to contact inherent in football was associated with a far lower rate of repeat concussions during the vital 10-day acute recovery period after the injury, when, the authors noted, “the brain appears to be particularly vulnerable to the effects of repetitive trauma.”

Taken together, these findings suggest a significant cultural shift in college football regarding how concussions are managed — namely, that a more conservative approach has taken root over the past 15 years.

McCrea added, “The aim of our research efforts over the past two decades has always been to have a translational impact on clinical care for student-athletes affected by concussion. These results from the NCAA-DOD CARE Consortium suggest that indeed research has informed international guidelines for concussion management, which result in improved health and safety for athletes.”

What’s next?

While the differences between the studies point to a significant shift, the analysis is not without limitations: Among others, the authors noted that the primary measure of recovery relies on self-reported symptoms and that the study did not isolate the effect of any one specific concussion management strategy relative to other factors that have changed in the intervening years between the studies.

Still, the data strongly suggest that the clinical approach to concussion management has grown more conservative in a relatively short time. That more cautious approach, the authors noted, allows adequate time for brain recovery after injury and reduces the risk of a repetitive concussion during the time when the brain is most vulnerable. That, they posit, “may be crucial to preventing persistent or chronic neurological health problems in athletes.”

Further studies are required to evaluate the impact longer periods between injury and return to play, and longer durations between repeat concussions, may have on longer-term health outcomes. Populations beyond the football student-athletes who were the focus of this research also require further examination.