Abstract P153: Low Diabetes Diagnosis and Treatment among Individuals with Fasting Blood Glucose Diagnostic of Diabetes is Associated with Income and Health Insurance Status in China, even after Control for Observable and Unobservable Factors
Authors: Attard Samantha M , Guilkey David K , Popkin Barry M , Zhang Bing , Mayer-Davis Elizabeth J , Meigs James B , Gordon-Larsen Penny 
Published: July 2021

Background:
The majority of Chinese adults with fasting blood glucose (FBG) diagnostic of diabetes (≥126 mg/dl) are not diagnosed or treated, placing them at high risk for cardiovascular disease-related complications. While demographic and economic factors might differentially predict each step in the continuum from having FBG diagnostic of diabetes to diagnosed and treated diabetes, most of the literature uses separate models to examine these three outcomes. Furthermore, most strategies ignore underlying, observable and unobservable individual and household factors that influence healthcare-seeking behavior and demand for treatment. We address these gaps, using a three-step sequential model to estimate FBG diagnostic of diabetes, diagnosed, and treated diabetes, correcting for observable and unobservable factors.

Methods:
Data came from 7,653 adults aged 18-75y in the 2009 wave of the China Health and Nutrition Survey, a prospective cohort study of economically diverse Chinese households in 9 provinces (228 communities). We used a Heckman-type system of equations to predict three steps: 1) FBG diagnostic of diabetes; 2) diagnosed diabetes (reported doctor diagnosis); and 3) treated diabetes (reported insulin or diabetes medication use), correcting for unobservable factors. We hypothesized differential prediction of each of the three steps by: age, gender, income (low, medium, or high tertiles), community health infrastructure (number/type of health facilities and pharmacies in or nearby (12 km) each community), and health insurance (none, low, medium, or high quality).

Results:
Eight percent (301 of 3,544) of men and 6% (248 of 4,059) of women had FBG diagnostic of diabetes. Using our three-step system of equations adjusting for observable and unobservable factors, income and health insurance were not statistically associated with FBG diagnostic of diabetes. Among individuals with FBG diagnostic of diabetes, 47% (95% confidence interval (CI): 44-50%) of high income versus 39% (CI: 36-42%) of low income individuals had diagnosed diabetes. Conditional on FBG≥126 mg/dl and diabetes diagnosis, treatment differed by health insurance quality: 47% (CI: 43-50%) of individuals with high quality insurance [relative to medium: 43% (CI: 39-47%), low: 34% (CI: 30-38%), and none: 29% (CI: 25-33%)] received diabetes treatment.

Discussion:
Using a three-step model and correcting for observable and unobservable factors, our findings suggest that, in China, income and health insurance play a stronger role in diabetes diagnosis and treatment than in having FBG diagnostic of diabetes. Our results from this unique modeling strategy highlight the stage in the diabetes continuum during which investment in diabetes treatment and screening is likely to have large impact.