Exploring uncertainty of the change from ICD-9 to ICD-10 on acute mortality effects of air pollution

Environ Int. 2008 Feb;34(2):248-53. doi: 10.1016/j.envint.2007.08.006. Epub 2007 Sep 12.


The change in ICD coding from ICD-9 to ICD-10 may produce inconsistencies and discontinuities in cause-specific mortality, thus impacting on effects estimates of air pollution on mortality. The current study was conducted in Wuhan, China. We examined the concordant rates and Kappa statistics using the mortality data from the year 2002 coded with both ICD-9 and ICD-10 codes and compared the estimated effects of air pollution using the Generalized Additive Model in R. We found high concordant rates (>99.3%) and Kappa statistics close to 1.0 (>0.98). Little difference was identified in the estimated effects of air pollution on daily cardiovascular, stroke, cardiac, cardiopulmonary, and respiratory mortality. This study provides evidence that, based on the wide definitions of cause-specific morality typically used in the studies of time-series air pollution mortality, the change in the ICD coding does not significantly affect the estimated effects of air pollution.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Air Pollutants / analysis
  • Air Pollutants / toxicity
  • Air Pollution / adverse effects*
  • Cause of Death*
  • China
  • Environmental Exposure / adverse effects
  • Humans
  • International Classification of Diseases / statistics & numerical data*
  • Nitrogen Dioxide / analysis
  • Nitrogen Dioxide / toxicity
  • Ozone / analysis
  • Ozone / toxicity
  • Particulate Matter / analysis
  • Particulate Matter / toxicity
  • Sulfur Dioxide / analysis
  • Sulfur Dioxide / toxicity
  • Uncertainty


  • Air Pollutants
  • Particulate Matter
  • Sulfur Dioxide
  • Ozone
  • Nitrogen Dioxide