Temporal trends in recording of diabetes on death certificates: results from Translating Research Into Action for Diabetes (TRIAD)

OBJECTIVE

To determine the frequency that diabetes is reported on death certificates of decedents with known diabetes and describe trends in reporting over 8 years.

RESEARCH DESIGN AND METHODS

Data were obtained from 11,927 participants with diabetes who were enrolled in Translating Research into Action for Diabetes, a multicenter prospective observational study of diabetes care in managed care. Data on decedents (N = 2,261) were obtained from the National Death Index from 1 January 2000 through 31 December 2007. The primary dependent variables were the presence of the ICD-10 codes for diabetes listed anywhere on the death certificate or as the underlying cause of death.

RESULTS

Diabetes was recorded on 41% of death certificates and as the underlying cause of death for 13% of decedents with diabetes. Diabetes was significantly more likely to be reported on the death certificate of decedents dying of cardiovascular disease than all other causes. There was a statistically significant trend of increased reporting of diabetes as the underlying cause of death over time (P < 0.001), which persisted after controlling for duration of diabetes at death. The increase in reporting of diabetes as the underlying cause of death was associated with a decrease in the reporting of cardiovascular disease as the underlying cause of death (P < 0.001).

CONCLUSIONS

Death certificates continue to underestimate the prevalence of diabetes among decedents. The increase in reporting of diabetes as the underlying cause of death over the past 8 years will likely impact estimates of the burden of diabetes in the U.S.In 2005, the National Center for Health Statistics ranked diabetes as the fifth leading cause of death in the U.S (1). Although it is difficult to determine the true extent to which diabetes should be recorded as a cause of death, this is likely an underestimate since diabetes is listed anywhere on the death certificate of fewer than half of people with known diabetes who die (2–5). Although using mortality data for epidemiologic studies is a common practice, it has drawbacks. When one studies mortality rates over time using death certificates one generally assumes that the likelihood of recording the condition remains constant over time, so that observed changes in mortality reflect true changes in the rate and not simply changes in recording practices. The last national study investigating trends in reporting of diabetes on death certificates used the 1986 and 1993 National Mortality Follow-back Survey and documented consistent underreporting over time (2). One smaller, more recent study looking at the sensitivity and specificity of reporting of diabetes on death certificates reported similar results (4).We hypothesize that diabetes reporting on death certificates may have improved since 2000 because of the increasing prevalence of diabetes and the increased media attention to diabetes. The objective of this study was to determine the frequency of reporting of diabetes on death certificates of decedents with known diabetes and to describe trends over 8 years using data from Translating Research into Action for Diabetes (TRIAD). TRIAD was ideal for this study because it involved a racially and ethnically diverse sample of adults with diabetes from six sites across the United States and because all participants had been diagnosed with diabetes for at least 1 year before enrollment.