Introduction: Air pollution is associated with adverse health outcomes. However,
its impact on emergency health services is less well understood. We investigated the
impact of air pollution on nation-wide emergency department (ED) visits and hospital
admissions to public hospitals in Singapore. Materials and Methods: Anonymised
administrative and clinical data of all ED visits to public hospitals in Singapore from
January 2010 to December 2015 were retrieved and analysed. Primary and secondary
outcomes were defined as ED visits and hospital admissions, respectively. Conditional
Poisson regression was used to model the effect of Pollutant Standards Index (PSI)
on each outcome. Both outcomes were stratified according to subgroups defined a
priori based on age, diagnosis, gender, patient acuity and time of day. Results: There
were 5,791,945 ED visits, of which 1,552,187 resulted in hospital admissions. No
significant association between PSI and total ED visits (Relative risk [RR], 1.002; 99.2%
confidence interval [CI], 0.995–1.008; P = 0.509) or hospital admissions (RR, 1.005;
99.2% CI, 0.996–1.014; P = 0.112) was found. However, for every 30-unit increase in
PSI, significant increases in ED visits (RR, 1.023; 99.2% CI, 1.011–1.036; P = 1.24 ×
10˗6) and hospital admissions (RR, 1.027; 99.2% CI, 1.010–1.043; P = 2.02 × 10˗5) for
respiratory conditions were found. Conclusion: Increased PSI was not associated with
increase in total ED visits and hospital admissions, but was associated with increased
ED visits and hospital admissions for respiratory conditions in Singapore.
Key words: Epidemiology, Healthcare utilisation, PSI, Public health, Time series