Validity of self-reported diabetes among middle-aged and older Chinese adults: the China Health and Retirement Longitudinal Study.

Background: Self-reported diabetes has been found to be valid to evaluate people's diabetes status in the population of several countries. However, no such study has been conducted to assess the validity of self-reported diabetes in the Chinese population, the largest population with the highest rate of diabetes. The aim of our study is to evaluate the validity of self-reported diabetes among the middle-aged and older Chinese population.

Methods: Data from 11 601 participants, aged ≥45, of the China Health and Retirement Longitudinal Study (CHARLS) during 2011-2012, were analysed. Prevalent self-reported diabetes was compared with reference definition defined by fasting glucose, glycated haemoglobin and medication use. Sensitivity, specificity, positive predicted value, negative predicted value and κ value were calculated overall, by 5-year age groups, by education levels and by living areas.

Results: The sensitivity of prevalent self-reported diabetes was 41.5%, and the specificity was 98.6%. The sensitivity of self-reported diabetes increased with education levels, and was much higher among urban residents than rural residents (58.2% vs 35.0%). The specificity was above 98% among all age groups, in different education levels, and in rural and urban areas. Self-reported diabetes had substantial agreement with reference definition among participants with above vocational school education or those living in urban areas (κ=0.658 and 0.646, respectively).

Conclusions: Although the sensitivity of self-reported diabetes was poor among middle-aged and older Chinese adults, the specificity and positive predictive values were fairly good. Furthermore, self-reported diabetes performed well among those with more than vocational school educations or those living in urban areas.