Methods and Limitations
We estimated the number and prevalence of self-reported cardiovascular disease conditions among the U.S. diabetic population aged 35 years or older using data from the National Health Interview Survey (NHIS) of the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention (CDC). Conducted continuously since 1957, NHIS is a health survey of the civilian, noninstitutionalized, household population of the United States. The survey provides information on the health of the U. S. population including information on the prevalence and incidence of disease, the extent of disability, and the use of health care services. The multistage probability design of the survey has been described elsewhere.1
Adult respondents were asked whether a health professional had ever told them they had diabetes. To exclude gestational diabetes, women were asked whether they had been told they had diabetes other than during pregnancy. Adult respondents were asked whether a health professional had told them that they had coronary heart disease, angina, a heart attack, any other kind of heart condition, heart disease, or a stroke. For our analyses coronary heart disease was defined as a positive response to one of the questions about coronary heart disease, angina, or heart attack. Responses to the questions on any other heart condition and stroke were analyzed separately. The respondents who chose “refused,” “don’t know,” or did not respond to questions for a condition were excluded from the analyses for that condition. The prevalence of these conditions was applied to the total number of people with diabetes to calculate the number of people with diabetes and cardiovascular disease conditions.
The prevalence estimates of self-reported cardiovascular disease in the diabetic population are presented by age, race, ethnicity, and sex. Three-year averages were used to improve the precision of the annual estimates. The race groups include persons of both Hispanic and non-Hispanic origin. People of Hispanic origin may be of any race. Estimates were age-adjusted using estimates of the 2000 U.S. population as the standard.
Approximately 1 of 4 persons with diabetes are unaware they have diabetes because their diabetes has not been diagnosed.2 Therefore, these data cannot describe the burden of cardiovascular disease among persons with undetected diabetes. In addition, NHIS data on history of diabetes and cardiovascular disease conditions are self-reported; however, studies have found self-reported cardiovascular conditions to be high in accuracy or only slightly higher than physician-reported rates,3-6 and the validity of self-reported diabetes is high for those with diagnosed diabetes.7
- Botman SL, Moore TF, Moriarity CL, Parsons VL. Design and estimation for the National Health Interview Survey, 1995–2004. Vital and Health Stat 2000;2(130).
- Centers for Disease Control and Prevention. National Diabetes Statistics Report: Estimates of Diabetes and Its Burden in the United States, 2014. Atlanta, GA: US Department of Health and Human Services; 2014.
- Kehoe R, Wu S-Y, Leske MC, Chylack LT Jr. Comparing self-reported and physician-reported medical history. American Journal of Epidemiology 1994;139:813–818.
- Engstad T, Bønaa, Viitanen M. Validity of self-reported stroke. The Tromsø Study. Stroke 2000;31:1602–1607.
- Bergmann MM, Byers T, Freedman DS, Mokdad A. Validity of self-reported diagnoses leading to hospitalization: A comparison of self-reports with hospital records in a prospective study of American adults. American Journal of Epidemiology 1998;147:969–977.
- Colditz GA, Martin P, Stampfer MJ, et al. Validation of questionnaire information on risk factors and disease outcomes in a prospective cohort study of women. American Journal of Epidemiology 1986;123:894–900.
- Saydah SH, Geiss LS, Tierney E, Benjamin SM, Engelgau M, Brancati F. Review of the performance of methods to identify diabetes cases among vital statistics, administrative, and survey data. Annals of Epidemiol 2004;14(7):507–516.