The relationship between age, workplace slips and the effectiveness of slip-resistant footwear among healthcare workers

Objectives. To explore any age-related trend in workplace slip rate and assess the effectiveness of appropriate slip-resistant footwear in preventing workplace slips by age. Methods. Secondary data analysis of the Stopping Slips among Healthcare Workers (SSHeW) trial, a two-arm randomised controlled trial conducted between March 2017 and May 2019. 4553 National Health Service (NHS) staff across seven sites in England were randomised 1:1 to the intervention group (provision of 5* GRIP-rated slip-resistant footwear) or the control group (usual work footwear). The primary outcome was self-reported workplace slips, ascertained primarily through weekly text messages throughout the 14-week trial follow-up and analysed using mixed effects negative binomial regression. This paper reports a control-group only analysis of the association between age and slip rate, and a full intention-to-treat analysis of the effectiveness of slip-resistant footwear by age. Results. The mean age of participants was 43 years (range 18-74). In the control-group only analysis, slip rate differed by age (p<0.001) with those aged 60+ having double the slip rate of those aged <30 years (95% CI 1.40-2.87). In the intention-to-treat analysis, the interaction between allocation and age was statistically significant (p=0.002). In addition, for all age groups except those aged <30 years, the slip rate in the intervention group was statistically significantly lower than the control group; the smallest incidence rate ratio (i.e., the biggest effect) was 0.39 (95% CI 0.25-0.65) in the 60+ age group. Conclusions. The provision of appropriate slip-resistant footwear was more effective at reducing workplace slips for older NHS staff. Keywords: Interventions; Occupational Injury; Randomised Trial; Workplace; Older People