Evidence map›Paper›PMID 21502355›Full record

ArticleCMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne2011

A prospective study of concussions among National Hockey League players during regular season games: the NHL-NHLPA Concussion Program.

Brian W Benson, Willem H Meeuwisse, John Rizos, Jian Kang, Charles J Burke

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Article in CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 61 papers, 5 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
61citing papers in PubMed, 5 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

61 citing papers in PubMed, 5 syntheses or guidelines pooled it.

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  9. Fist fighting and increased mortality post-retirement among National Hockey League players.Canadian journal of public health = Revue canadienne de sante publique · 2025
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1 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

5 authors.

Brian W BensonSport Medicine Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alta. bbenson@ucalgary.ca
Willem H Meeuwisse
John Rizos
Jian Kang
Charles J Burke

Funding

Canadian Institutes of Health Research
6 · The paper itself

Abstract

backgroundIn 1997, the National Hockey League (NHL) and NHL Players' Association (NHLPA) launched a concussion program to improve the understanding of this injury. We explored initial postconcussion signs, symptoms, physical examination findings and time loss (i.e., time between the injury and medical clearance by the physician to return to competitive play), experienced by male professional ice-hockey players, and assessed the utility of initial postconcussion clinical manifestations in predicting time loss among hockey players.

methodsWe conducted a prospective case series of concussions over seven NHL regular seasons (1997-2004) using an inclusive cohort of players. The primary outcome was concussion and the secondary outcome was time loss. NHL team physicians documented post-concussion clinical manifestations and recorded the date when a player was medically cleared to return to play.

resultsTeam physicians reported 559 concussions during regular season games. The estimated incidence was 1.8 concussions per 1000 player-hours. The most common postconcussion symptom was headache (71%). On average, time loss (in days) increased 2.25 times (95% confidence interval [CI] 1.41-3.62) for every subsequent (i.e., recurrent) concussion sustained during the study period. Controlling for age and position, significant predictors of time loss were postconcussion headache (p < 0.001), low energy or fatigue (p = 0.01), amnesia (p = 0.02) and abnormal neurologic examination (p = 0.01). Using a previously suggested time loss cut-point of 10 days, headache (odds ratio [OR] 2.17, 95% CI 1.33-3.54) and low energy or fatigue (OR 1.72, 95% CI 1.04-2.85) were significant predictors of time loss of more than 10 days.

interpretationPostconcussion headache, low energy or fatigue, amnesia and abnormal neurologic examination were significant predictors of time loss among professional hockey players.

Indexed as

AdolescentAdultBrain ConcussionCanadaHockeyHumansLinear ModelsLogistic ModelsMaleProspective StudiesSick LeaveStatistics, NonparametricYoung Adult

Identifiers

PMID21502355
PMCPMC3091898

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.