Awareness, Accuracy, and Predictive Validity of Self-Reported Cholesterol in Women

BACKGROUND: Although current guidelines emphasize the importance of cholesterol knowledge, little is known about accuracy of this knowledge, factors affecting accuracy, and the relationship of self-reported cholesterol with cardiovascular disease (CVD). METHODS: The 39,876 female health professionals with no prior CVD in the Women’s Health Study were asked to provide self-reported and measured levels of total and high-density lipoprotein (HDL) cholesterol. Demographic and cardiovascular risk factors were considered as determinants of awareness and accuracy. Accuracy was evaluated by the difference between reported and measured cholesterol. In addition, we examined the relationship of self-reported cholesterol with incident CVD over 10 years. RESULTS: Compared with women who were unaware of their cholesterol levels, aware women (84%) had higher levels of income, education, and exercise and were more likely to be married, normal in weight, treated for hypertension and hypercholesterolemia, nonsmokers, moderate drinkers, and users of hormone therapy. Women underestimated their total cholesterol by 9.7 mg/dL (95% CI: 9.2–10.2); covariates explained little of this difference (R(2) < .01). Higher levels of self-reported cholesterol were strongly associated with increased risk of CVD, which occurred in 741 women (hazard ratio 1.23/40 mg/dL cholesterol, 95% CI: 1.15–1.33). Women with elevated cholesterol who were unaware of their level had particularly increased risk (HR=1.88, P <. 001) relative to aware women with normal measured cholesterol. CONCLUSION: Women with obesity, smoking, untreated hypertension, or sedentary lifestyle have decreased awareness of their cholesterol levels. Self-reported cholesterol underestimates measured values, but is strongly related to CVD. Lack of awareness of elevated cholesterol is associated with increased risk of CVD

Validation of self diagnosis of high blood pressure in a sample of the Spanish EPIC cohort: overall agreement and predictive values

STUDY OBJECTIVE—High blood pressure is a variable related to several chronic conditions whose repeated measurement in large cohort studies is often not feasible having to rely on the self reporting of the subjects. The aim of the study is to validate such self diagnosis in a sample of members from the Spanish EPIC cohort study.
DESIGN—Comparison of high blood pressure self diagnosis with the information provided by the personal medical record drawn from the primary health centre of reference for such population.
SETTING—A small town near the EPIC-Murcia centre, one of five Spanish EPIC centres located in the south east, where inclusion in the cohort was offered to the general population.
PARTICIPANTS—The agreement between self reported high blood pressure status and data from medical records was measured in a representative sample of men and women (n= 248) aged 30-69 years. Medical records were studied for a diagnosis of high blood pressure, an anti-hypertensive pharmacological treatment or subject's inclusion in a hypertension control programme run in the medical centre only for hypertensive people (definite high blood pressure cases). As well, in the absence of such a diagnosis, medical annotations of systolic or diastolic high blood pressure⩾ 140/90 mm Hg (possible high blood pressure cases) were considered. Sensitivity, specificity, positive and negative predictive values and κ scores were calculated for all, definite and possible high blood pressure cases. Variables associated with the probability of having a true positive or negative self report of high blood pressure were also tested.
MAIN RESULTS—As expected, sensitivity was higher among definite cases (72.7%) than among possible cases (31.6%). Accordingly, the agreement between self report and medical record was higher for definite cases (κ = 0.65) than for possible (κ = 0.29) cases leading to a moderate overall agreement for all cases (κ = 0.58; 95% CI: 0.47, 0.69). Having some level of education (OR: 0.31; 95% CI: 0.09, 1.05) was negatively associated to a true self report of high blood pressure while being female was positively associated (OR: 4.01; 95% CI: 1.04, 16.8). No variable showed any association with having a true self report of being normotensive.
CONCLUSIONS—High blood pressure self report shows a moderate agreement with medical information in this cohort allowing it to be used, with caution, as a surrogate variable of actual blood pressure status. However, because of its moderate sensitivity, it is not possible to rule out some underestimation when using self reported high blood pressure information for high blood pressure frequency measurements such as prevalence or incidence rates. This underestimation will be higher among men and educated people.


Keywords: hypertension; high blood pressure; validation; agreemen