Recorded presentation

Gary S. Sorock, PhD¹, David A. Lombardi, PhD², David Fisman, MD, MPH³, Anthony D Harris, MD, MPH⁴, Theodore K. Courtney, MS, CSP², Bradley Evanoff, MD, MPH⁵, Gordon S. Smith, MD, MPH², and Murray A. Mittleman, MD, DrPH⁶. (1) Johns Hopkins Bloomberg School of Public Health, Center for Injury Research and Policy, 624 N. Broadway, Room 545, Baltimore, MD 21205, 443-287-0103, gsorock@jhsph.edu, (2) Quantitative Analysis Unit, Liberty Mutual Research Institute for Safety, 71 Frankland Road, Hopkinton, MA 01748, (3) Epidemiology and Biostatistics, Drexel School of Public Health, 245 N. 15th Street, Mail Stop 660, Philadelphia, PA 19102-1192, (4) Department of Epidemiology and Preventve Medicine, University of Maryland, Baltimore, School of Medicine, 100 N. Greene St., Medical Service Rm 5D-151, Baltimore, MD 21201, (5) Division of General Medical Sciences, Washington University School of Medicine, Campus box 8005, 660 South Euclid Ave, St. Louis, MO 63110, (6) Epidemiology, Harvard School of Public Health, 665 Huntington Avenue, Boston, MA 02115

The case-crossover epidemiological design is used to evaluate transient risk factors such as distraction or rushing at the time of a sudden-onset event. However, its use in injury research raises some methodological issues. This paper seeks to address these issues using data from our case-crossover studies of hand injuries, falls, needle-stick injuries, and medication errors. Our study of occupational acute hand injury found relative risks (RR, 95% confidence intervals) over twice as high when distracted (5.3, CI 4.6-6.1) than when rushed (2.4, CI 2.4-2.7), and similarly, in our study of sharps-related injuries, the relative risks were higher when distracted (8.9, CI 5.1-16.0) than when rushed 3.3 (2.5-5.0). Data from the first study indicate that subjects reported a far shorter median number of minutes per episode of distraction than rushing: 8 min vs. 120 min. Thus, a shorter-term exposure, distraction, was associated with a higher risk of hand injury than rushing.

These findings raise questions such as: 1) Do people compensate for rushing by reducing other risk behaviors that they cannot do when distracted? 2) What is the validity of self-reported duration of distraction and rushing in injured and non-injured time periods? 3) Since distraction and rushing often occur together, how best can we control within-person confounding by simultaneously occurring transient risk factors? 4) How can we intervene to reduce the duration of short-term risk factors and the injury risk associated with these exposures? This methodological paper will address each of these questions based on the studies mentioned above.

Learning Objectives: At the conclusion of the session, the learner will be able to

• describe the strengths and limitations of the case-crossover design for injury epidmeiology
• identify research questions for consideration when using the case-crossover design in injury epidemiology
• consider how the study design might be used in the context of an injury problem of interest to the learner

Keywords: Injury Risk, Methodology

Presenting author's disclosure statement:
I do not have any significant financial interest/arrangement or affiliation with any organization/institution whose products or services are being discussed in this session.

Recorded presentation