title: Trends in concussion return-to-play timelines among high school athletes from 2007 through 2009.
abstract: BACKGROUND
  Whereas guidelines about return-to-play (RTP) after concussion have been published, actual prognoses remain elusive.
  
  
  OBJECTIVE
  To develop probability estimates for time until RTP after sport-related concussion.
  
  
  METHODS
  Descriptive epidemiology study.
  
  
  METHODS
  High school.
  
  
  METHODS
  Injured high school varsity, junior varsity, or freshman athletes who participated in 1 of 13 interscholastic sports at 7 area high schools during the 2007-2009 academic years.
  
  
  METHODS
  Athletic trainers employed at each school collected concussion data. The athletic trainer or physician on site determined the presence of a concussion. Athlete-exposures for practices and games also were captured.
  
  
  METHODS
  Documented concussions were categorized by time missed from participation using severity outcome intervals (same-day return, 1- to 2-day return, 3- to 6-day return, 7- to 9-day return, 10- to 21-day return, >21-day return, no return [censored data]). We calculated Kaplan-Meier time-to-event probabilities that included censored data to determine the probability of RTP at each of these time intervals.
  
  
  RESULTS
  A total of 81 new concussions were documented in 478 775 athlete-exposures during the study period. After a new concussion, the probability of RTP (95% confidence interval) was 2.5% (95% confidence interval = 0.3, 6.9) for a 1- to 2-day return, 71.3% (95% confidence interval = 59.0, 82.9) for a 7- to 9-day return, and 88.8% (95% confidence interval = 72.0, 97.2) for a 10- to 21-day return.
  
  
  CONCLUSIONS
  For high school athletes, RTP within the first 2 days after concussion was unlikely. After 1 week, the probability of return rose substantially (approximately 71%). Prognostic indicators are used to educate patients about the likely course of disease. Whereas individual symptoms and recovery times vary, prognostic time-to-event probabilities allow clinicians to provide coaches, parents, and athletes with a prediction of the likelihood of RTP within certain timeframes after a concussion.
authors.affiliation: Department of Exercise & Sport Sciences, Ithaca College, NY.
authors.forename: Jennifer M Medina
authors.initials: JM
authors.lastname: McKeon
authors.forename: Scott C
authors.initials: SC
authors.lastname: Livingston
authors.forename: Ashley
authors.initials: A
authors.lastname: Reed
authors.forename: Robert G
authors.initials: RG
authors.lastname: Hosey
authors.forename: Williams S
authors.initials: WS
authors.lastname: Black
authors.forename: Heather M
authors.initials: HM
authors.lastname: Bush
mesh_terms: D000293:Adolescent; D056352:Athletes; D001265:Athletic Injuries / Q000453:epidemiology* / Q000534:rehabilitation*; D001924:Brain Concussion / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D062707:Return to Work / Q000706:statistics & numerical data*; D012574:Schools; D013177:Sports; D013334:Students