What do chronic obstructive pulmonary disease patients die from? A multiple cause coding analysis.

Information on obstructive lung disease (OLD) deaths is generally derived from the underlying cause of death on the death certificate. This neglects information on other conditions mentioned and may underestimate the burden of disease. Descriptive analyses of all conditions mentioned on the death certificate for all decedents where OLD (chronic obstructive pulmonary disease or asthma) was mentioned as a contributing cause of death were conducted for England and Wales for 1993-1999. OLD was mentioned in 312,664 or 8.0% of all deaths. OLD comprised the underlying cause of death in 59.8% of deaths with any mention of OLD. Where OLD was not the underlying cause of death, the leading causes by the International Classification of Disease version 9 chapter were diseases of the circulatory system, neoplasms, and non-OLD diseases of the respiratory system. The top single causes were acute myocardial infarction, other ischaemic heart disease, and lung cancer. The current analysis confirms that using the underlying cause of death underestimates the contribution of obstructive lung disease to mortality in England and Wales, in contrast to myocardial infarction where underlying cause of death captures most (94%) mentions on the death certificate.