Progress in the Estimation of Mortality due to Diabetes

In this issue, Roglic et al. (1) provide new estimates of the proportion of deaths worldwide attributable to diabetes. Their result is about three times as high as a prior estimate from the World Health Organization in 2002. The World Health Organization estimate was based on the underlying cause of death listed on death certificates and likely underestimated the contribution of this disorder to mortality, as underrecording of diabetes on death certificates has been demonstrated in several studies (2–4).

Further issues make use of death certificates to assess cause of mortality problematic. Recording of diabetes is likely to be inconsistent due to the lack of a standardized method for death certificate coding. Contrast this situation with a clinical research study that applied specific criteria to assign a cause of death. Such rigor would never be possible in the “real” world because of educational and practice differences regionally and nationally, as well as the current emphasis on the judgment of an individual physician in assigning cause of death. The idea of having a clinician assign cause of death seems sound, but the lack of standardization will lead to uncertainty about the meaning and inclusiveness of causes listed on death certificates.

Causal interpretations and competing causes of mortality also must be considered in interpreting and estimating causes of death. Diabetes may lead to the immediate cause of death by, for example, causing cardiovascular disease but remain unlisted on the death certificate since it was one or more steps removed from the terminal event. Conversely, the presence of diabetes in the deceased does not necessarily mean that diabetes contributed to mortality, as might be the case if death occurred due to non–hypoglycemia-related trauma, drowning, or another condition that is not likely …