title: Cost saving potential in cardiovascular hospital costs due to reduction in air pollution.
abstract: OBJECTIVE
  We describe a methodological framework to estimate potential cost savings in Belgium for a decrease in cardiovascular emergency admissions (ischemic heart disease (IHD), heart rhythm disturbances (HRD), and heart failure) due to a reduction in air pollution.
  
  
  METHODS
  Hospital discharge data on emergency admissions from an academic hospital were used to identify cases, derive risk functions, and estimate hospital costs. Risk functions were derived with case-crossover analyses with weekly average PM10, PM2.5, and NO2 exposures. The risk functions were subsequently used in a micro-costing analysis approach. Annual hospital cost savings for Belgium were estimated for two scenarios on the decrease of air pollution: 1) 10% reduction in each of the pollutants and 2) reduction towards annual WHO guidelines.
  
  
  RESULTS
  Emergency admissions for IHD and HRD were significantly associated with PM10, PM2.5, and NO2 exposures the week before admission. The estimated risk reduction for IHD admissions was 2.44% [95% confidence interval (CI): 0.33%-4.50%], 2.34% [95% CI: 0.62%-4.03%], and 3.93% [95% CI: 1.14%-6.65%] for a 10% reduction in PM10, PM2.5, and NO2 respectively. For Belgium, the associated annual cost savings were estimated at € 5.2 million, € 5.0 million, and € 8.4 million respectively. For HRD, admission risk could be reduced by 2.16% [95% CI: 0.14%-4.15%], 2.08% [95% CI: 0.42%-3.70%], and 3.46% [95% CI: 0.84%-6.01%] for a 10% reduction in PM10, PM2.5, and NO2 respectively. This corresponds with a potential annual hospital cost saving in Belgium of € 3.7 million, € 3.6 million, and € 5.9 million respectively. If WHO annual guidelines for PM10 and PM2.5 are met, more than triple these amounts would be saved.
  
  
  CONCLUSIONS
  This study demonstrates that a model chain of case-crossover and micro-costing analyses can be applied in order to obtain estimates on the impact of air pollution on hospital costs.
authors.affiliation: Interuniversity Centre for Health Economics Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium. Electronic address: sdevos@vub.ac.be.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Devos
authors.affiliation: Centre for Environmental Sciences, Hasselt University, Agoralaan building D, 3590 Diepenbeek, Belgium.
authors.forename: Bianca
authors.initials: B
authors.lastname: Cox
authors.affiliation: Interuniversity Centre for Health Economics Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
authors.forename: Stijn
authors.initials: S
authors.lastname: Dhondt
authors.affiliation: Centre for Environmental Sciences, Hasselt University, Agoralaan building D, 3590 Diepenbeek, Belgium; Department of Public Health, University of Leuven (KU Leuven), Herestraat 49, 3000 Leuven, Belgium.
authors.forename: Tim
authors.initials: T
authors.lastname: Nawrot
authors.affiliation: Interuniversity Centre for Health Economics Research, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Putman
mesh_terms: D000397:Air Pollution / Q000706:statistics & numerical data*; D001530:Belgium / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D017046:Cost Savings; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D017721:Hospital Costs / Q000706:statistics & numerical data*
keywords: Air pollution; Cardiovascular diseases; Case-crossover analysis; Hospital costs; Micro-costing analysis approach