Relationship between Body Mass Index Categories and Expenditures Over Time among Veteran Health Administration Users with Newly Diagnosed Diabetes

Shen Y, Sambamoorthi U, Soroka O, Rajan M, Pogach LM. Relationship between Body Mass Index Categories and Expenditures Over Time among Veteran Health Administration Users with Newly Diagnosed Diabetes. Paper presented at: AcademyHealth Annual Research Meeting; 2012 Jun 25; Orlando, FL.

Related HSR&D Project(s)

• IIR 05-261 – Longitudinal Analysis of Utilization and Cost by VA Patients with Diabetes

Research Objective: To study relationship between body mass index (BMI) categories and healthcare expenditures. Study Design: Total annual expenditures (VHA and Medicare) were evaluated from 1999 through 2004. BMI values recorded in 1999 were grouped into four categories: normal (18.5-24.9) overweight (25-29.9), obese (30 - 34.9) and morbidly obese ( > = 35). Generalized linear models were fit to examine the association between 1999 BMI categories and annual expenditures over time controlling for demographic, socio-economic, health status, and lifestyle risk factors. Population Studied: The study sample comprised of respondents of the 1999 Large Veteran Health Survey with newly diagnosed with diabetes in 1999, identified using linked VHA and Medicare data and a previously validated algorithm and followed until 2004. Principal Findings: Overall, 12.8% of veterans with newly diagnosed diabetes were normal weight, 46% overweight, 25% obese and 13% morbid obese. The average expenditures were lowest($7,006) for obese group in 1999 and highest for morbid obese($12,052) in 2004. In both bivariate and multivariate analyses, the relationship between BMI categories and expenditures changed over time. For example, during the first year of incident diagnosis (i.e. in 1999), compared to veterans with normal BMI those with obesity had lower expenditures. However, in 2004, the relationship reversed. Compared to veterans with normal BMI, those with obesity had greater expenditures. In a pooled model with year as one of the covariates, the interaction term between time and BMI categories was positive for all the categories. Conclusions: The relationship between BMI categories and total healthcare expenditure is complex and varies over time. As time progressed, the rate of growth in expenditures were greater for veterans who were overweight, obese and morbid obese. Implications for Policy, Delivery or Practice: Understanding the relationships between obesity and expenditures over time is critical to approaches that focus on pathways to reducing expenditures in veterans with chronic illnesses such as diabetes.