Heart failure describing the underlying cause of death: a misconception, lack of information on the true underlying causes, or both?

Aim: The underlying cause of death represents the most important information on death certificates. Often, conditions that cannot represent a true underlying cause of death are listed as such. This phenomenon affects the quality of vital statistics and results of studies using cause-specific mortality as endpoints. We aimed at exploring the magnitude and factors associated with the use of heart failure to describe the underlying cause of death. Methods: In this cross-sectional, register based study we linked data from the Norwegian Cause of Death Registry and the Norwegian Patient Registry. We used logistic regression models to analyse the association between external factors and heart failure listed as the underlying cause of death. Results: Heart failure was listed as the underlying cause of death in 3.6% of all deaths. The odds of heart failure increased: (a) by 35% for 5-year increment in age; (b) by 78% for deaths occurring at nursing homes (compared with in-hospital deaths); and (c) by 602% for deaths not followed by an autopsy (compared with those followed by an autopsy). Deceased with a previous hospitalisation with heart failure as the discharge diagnosis had 514% higher odds of having heart failure listed as their underlying cause of death. Of the deceased with heart failure listed as the underlying cause of death, 9.4% did not have any, and 69.2% had only irrelevant additional information for assessing the true underlying cause of death in their death certificates. Conclusions: Heart failure listed as the underlying cause of death was associated with age, place of death, autopsy and previous hospitalisations - all factors that should not influence coding procedures. Better completion of death certificates in accordance with the World Health Organization rules will help reduce the use of heart failure to describe the underlying cause of death.