Background Setting physical barriers, for example platform screen doors (PSDs), has been proven to be effective in preventing falls onto railway tracks, but its cost-effectiveness is not known. For economic evaluation of public health interventions, the importance of including non-health factors has been noted despite a lack of empirical studies. This study aimed to investigate the effectiveness and cost-effectiveness of PSDs, which are installed in part of the Hong Kong railway system, for preventing railway injuries.

Methods Data on railway injuries from 1997 to 2007 were obtained from the railway operators. Poisson regression was used to examine the risk reduction. Two incremental cost-effectiveness ratios (ICER) were calculated to assess the cost-effectiveness based on (1) disability-adjusted life years (DALYs) only and (2) DALYs with potential fare revenue and passengers' waiting time lost due to railway circulation collapse.

Results The PSD installation has effectively reduced railway injuries (adjusted 5-year average percentage change: −68.8%, p<0.0001) with no apparent substitution effect to the other platforms observed. To be cost-effective, the cost of gaining a healthy life year (ICER) should not exceed three times the per capita GDP (US$74 700). The PSD installation would only be cost-effective if the loss of fare revenue and passengers' waiting time, in addition to DALY, were included (ICER: US$65 400), while the ICER based on DALY only would be US$77 900.

Conclusion The challenges of complexity for economic evaluation appear in many community-based health interventions. A more extensive perspective for exploring other outcome measurements and evaluation methods to reflect a fair and appropriate value of the intervention's cost-effectiveness is needed.