The price of personal mobility: burden of injury and mortality from personal mobility devices in Singapore - a nationwide cohort study.

Background: Personal mobility devices (PMDs) like skate-scooters, electric bicycles (e-bikes) or motorised scooters (e-scooters) have become widely available globally. There are several studies describing the rising incidence of injury from such devices. The aim of our study was to examine PMD user factors between motorised (MotPMDs) vs non-motorised PMDs (NonPMDs) as risk factors for severe injury and the need for hospital admission.

Methods: We analysed de-identified National Trauma Registry data (2015 to 2017) from all public sector hospitals in Singapore for patients aged 12 and above presenting to emergency departments with PMD-related injuries. Multivariable logistic regression was used to identify risk factors for the primary outcome of interest (higher injury severity, defined as Injury Severity Score / ISS > =9), and the secondary outcome of interest (need for hospital admission). Additional subgroup analysis was conducted comparing only scooters (manual vs electric), the most common sub-type of PMD in our study.

Results: Of the 614 patients in our study, majority were male (74%), median age 33 years, with 136 (22%) sustaining injuries with ISS > =9; 185 (30%) admitted [median stay length 3 days (IQR: 1-6)] and 93 (15%) required surgery. MotPMDs were more common (480, 78%), with e-scooters being the most common motorised device (393, 64%). There were 6 deaths, all in MotPMD users. On both univariate and multivariable regression, MotPMD users [OR 3.82, 95% CI 1.51-12.9, p = 0.01] and older users (> = 60 years) [OR 9.47, 95% CI 2.45-62.9, p = 0.004] were more likely to sustain injuries with ISS > =9, and more likely to need admission (MotPMD users [OR 1.8, 95% CI 1.04-3.29, p = 0.045], age > =60 years [OR 4.72, 95% CI 1.86-13.0, p = 0.002]).

Conclusion: MotPMDs tripled the risk of severe injury and doubled the risk of requiring hospitalisation, compared to NonPMDs, likely due to higher travelling speeds. Increased age was also associated with severe injury and requiring hospitalisation.