Diabetes Reporting on Death Certificates in Kentucky, 2002-2003

1. Diabetes Reporting on Death Certificates in Kentucky, 2002-2003 Melonie Heron, Ph.D. & Robert N. Anderson, Ph.D. Mortality Statistics Branch Division of Vital Statistics Centers for Disease Control and Prevention National Center for Health Statistics

2. Outline • Background: Death certificate layout and cause of death coding issues • Diabetes reporting on death certificates • Kentucky diabetes checkboxes • Pros and cons • Descriptive results and effects on diabetes reporting • Alternative methodology

3. US Standard Death Certificate

4. US Standard Death Certificate

5. US Standard Death Certificate Acute renal failure Hyperosmolar nonketotic coma Diabetes mellitus, non insulin dependent

6. US Standard Death Certificate Acute renal failure Hyperosmolar nonketotic coma Diabetes mellitus, non insulin dependent

7. US Standard Death Certificate Acute renal failure Hyperosmolar nonketotic coma Diabetes mellitus, non insulin dependent Hypertension, Previous myocardial infarction

8. Cause of Death Coding and Statistics • All information reported in Parts I and II is coded (up to 20 conditions) • Conversely, cause of death information not recorded in Parts I or II does not get coded or entered into mortality database • Underlying cause of death is selected from among the conditions reported • Mortality statistics usually based on underlying cause of death

9. Issues in the reporting of diabetes on the death certificate • Certifier may not know about a diagnosis of diabetes or its relation to other co-morbid conditions • Causal sequence not always obvious in the presence of other co-morbid conditions • Diabetes most often reported in Part II

10. Kentucky Death Certificate

11. Diabetes Checkbox Questions Implemented in July of 2002 in Kentucky • Did the deceased have Diabetes? • Was Diabetes an immediate, underlying, contributing cause of or condition leading to death?

12. Upside of checkbox questions • 1st question - Ability to identify diabetic decedents • 2nd question indicates whether diabetes should have been reported in Part I or II • May help assess underreporting of diabetes in the cause of death section of the death certificate • Reminder to certifier to report diabetes

13. Downside of checkbox questions • Could result in underreporting in cause of death (COD) section of the death certificate • Cause of death coding standards and rules • Causes not reported in COD section are not coded • Causes not coded do not make it into official statistics or data release • Loss of detail – no info about type of diabetes

14. Results: 12,320 KY death certificates with “yes” to at least one of the questions

15. Results: Responses in Checkbox 1 vs. Reported Cause of Death

16. Results: Responses in Checkbox 2 vs. Reported Cause of Death

17. What does Checkbox 2 tell us? • Diabetes is not reported in the cause of death section in about 40% of cases in which diabetes is identified as an immediate, underlying or contributing cause • But…is this checkbox question an indicator or a cause of underreporting?

18. Do the Checkboxes Have an Effect on the Trend in Diabetes Reporting?

19. Diabetes Deaths: US, 1990-2003

20. Diabetes Deaths: Kentucky, 1990-2003

21. Diabetes Deaths: US, 1990-2003

22. Diabetes Deaths: Kentucky, 1990-2003

23. Conclusions • The diabetes checkboxes clearly have a marked effect on where (Part I or II) diabetes is reported • Increases in Part I and decreases in Part II • Slight increase in diabetes as the underlying cause of death • Decrease in overall reporting of diabetes

24. Alternative Methodology • Can use national health surveys linked to mortality data to: • Explore the extent to which diabetes is reported as a cause of death for those who self-reported diabetes. • Analyze the impact of diabetes on risk of mortality, generally and by cause of death

25. NHIS-NDI Linked Data • National Health Interview Survey (NHIS) • National survey conducted annually by NCHS since 1957 • Monitors the health of the U.S. population • National Death Index (NDI) • National file of death record information compiled by NCHS from state registries • Deaths added annually, 1979-present • Helps researchers determine the mortality status of study participants

26. Study Approach • Linked NHIS and NDI files for 1997 to 2000 • Includes mortality follow up of NHIS participants until 2002 • Restricted analyses to survey participants who were eligible for follow up and determined to be dead • Compared self-reports of diabetes on the survey to subsequent recording of diabetes as a cause of death on the death certificate

27. Percent of deceased diabetics for whom diabetes was reported as a cause of death, NHIS-NDI Linked Data, 1997-2002

28. Future Linked Data Research • Trends in self-reports of diabetes vs. death certificate recording of diabetes • Extend analyses past 2002 • Any changes in the Kentucky trends? (assuming sufficient number of observed deaths) • Trends in mortality from other causes of death for diabetic decedents • Analyze risk of death from diabetes and other causes using multivariate modeling

29. THE END Contacts: mheron@cdc.gov, RNAnderson@cdc.gov