Self-report of high cholesterol: determinants of validity in U.S. adults.
BACKGROUND
Hypercholesterolemia is a major cardiovascular risk factor, and cholesterol awareness is important in both clinical practice and in public health. We evaluated the validity of self-reported hypercholesterolemia and identified determinants of validity.


METHODS
The study design was a cross-sectional survey, from 1988 to 1994, of adult participants (N=8236) from the Third National Health and Nutrition Examination Survey for whom self-report of hypercholesterolemia and serum measurement were available. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for self-reported hypercholesterolemia were calculated using total cholesterol > or =5.17 mmol/L (200 mg/dL) and/or taking cholesterol-lowering medication as the criterion standard.


RESULTS
Overall test characteristics for self-report were sensitivity, 51%; specificity, 89%; PPV, 87%; and NPV, 55%. Sensitivity of self-report was higher among older subjects and non-Hispanic whites, specificity was higher among subjects with >12 years of education, PPV was higher in older subjects, and NPV was higher in younger subjects and in those with >12 years of education. Using higher cholesterol thresholds to define hypercholesterolemia led to higher sensitivity, lower specificity, lower PPV, and higher NPV. Sociodemographic and anthropometric predictors of validity were identified by logistic regression.


CONCLUSIONS
Due to low sensitivity, self-reported hypercholesterolemia should be used with caution, both during the patient encounter and for surveillance of trends in hypercholesterolemia in the absence of measured cholesterol levels. Specificity is consistently much higher than sensitivity. The high PPV may be of use in certain clinical situations. Such validation studies should form the foundation for future research based on self-report.
Natarajan
Sundar
S
Ralph H. Johnson Veterans Affairs Medical Center, Medical University of South Carolina, Charleston, USA. nataraja@musc.edu
Lipsitz
Stuart R
SR
Nietert
Paul J
PJ
D000328:Adult; D000368:Aged; D015992:Body Mass Index; D004522:Educational Status; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia; D007182:Income; D008297:Male; D008875:Middle Aged; D012107:Research Design; D012680:Sensitivity and Specificity