Published in International Journal of the Care of the Injured on 26 January 2013

V.X.Y. Chiang 2, J.Y.X. Cheng 1, Z.C. Zhang 3, L.T. Teo 1
1 Trauma Services, Department of General Surgery, Tan Tock Seng Hospital, Singapore
2 Yong Loo Lin School of Medicine, National University of Singapore, Singapore
3 Department of Biostatistics, Tan Tock Seng Hospital, Singapore



Motorcyclists and their pillion riders are the most vulnerable group of road users in Singapore, accounting for 50% of all road traffic accident fatalities in 2011. This study aims to compare the severity and pattern of injuries between matched pairs of riders and pillions.


Thirty-two matched pairs who presented to the A&E of an urban hospital from 1 August 2011 to 20 March 2012 were enrolled. Data were obtained from the hospital’s trauma registry records, clinical records and accident victims were interviewed individually. Analysis was done using Stata 10 and considered rider-pillion pairs.


Thirty-one pairs agreed to participate. There was no statistically significant difference in the ISS between riders and pillions (p = 0.25). There was no significant difference in the probability of survival, Revised Trauma Score, distribution of injuries, total duration of admission and ICU stay between riders and pillions. When one party of the matched pair sustained a head, face, thoracic, abdominal/pelvic, extremity or external injury, the likelihood that the other party had an injury in the same region was 31%, 14%, 10%, 14%, 56% and 68% respectively. Cohen’s kappa values were 0.28, 0.15, 0.05, 0.17, 0.24 and 0.16 for the respective regions.


By comparing the severity and pattern of injuries between naturally matched pairs on the same motorcycle, one can account for potential confounding by the type and impact of collision, rider experience, amount of time to availability of medical aid, and other factors that may influence the outcome. Our study shows no statistically significant difference in the ISS and distribution of injuries between riders and pillions of matched pairs. Therefore, future health and insurance policies should provide equal coverage for both riders and pillions. Medical practitioners should approach riders and pillions similarly as there is no significant difference in their injury distribution. When one party of a matched pair presents with a head, extremity or external injury, care should be taken to look for an injury in the same region in the other party.


Our study shows that there is no statistically significant difference in the ISS of riders and pillions. The pattern of injury is also similar. This study provides us useful information in the clinical management of motorcyclists and their pillions.

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