Underestimation of mortality due to chronic obstructive pulmonary disease (COPD) in Kentucky

Chronic obstructive pulmonary disease (COPD) mortality may be underestimated because it is frequently listed as a contributory cause of death, rather then the underlying cause of death, on state death certificates. Contributory causes of death are not counted in mortality statistics. This may underestimate the true burden of disease.

Determine the frequency in which COPD is listed as a contributory cause of death, rather than the underlying cause of death, per state mortality records for a one-year period, year 2000.

15,036 mortality records from Kentucky death certificates were examined for year 2000 for all deaths due to diseases most often associated with COPD; notably, heart disease, pneumonia/influenza, and asthma.

Cases in which COPD was listed as a contributory cause of death for asthma, pneumonia and influenza was small (less than 1%). Cases in which COPD was listed as a contributory cause of death for heart disease was much higher at 6.8% (824 out of 12,084). Counting these cases increases the COPD age-adjusted mortality rate 39%, from 52.4 to 72.7/ 100,000 people.

This study provided evidence to generate and support the hypothesis that COPD mortality is underestimated in Kentucky when the underlying cause of death is heart disease, thus underestimating the true burden of disease. COPD is a chronic, often severe disease commonly associated with comorbid conditions such as heart disease that ultimately lead to death, but which may not be accurately reflected in mortality statistics. Accurate reporting is essential for health planning, education, research, and treatment options.