Date of Graduation


Document Type


Degree Type



School of Pharmacy


Pharmaceutical Systems and Policy

Committee Chair

Usha Sambamoorthi.


Purpose. The main objective of the study was to estimate the short-term changes in healthcare expenditures that result from weight gain or loss in a population of Medicare patients using longitudinal data. Changes in total healthcare expenditures and its components (inpatient, outpatient, prescription, dental and other) by changes in body mass index (BMI) categories were analyzed.;To examine the relationship between BMI changes and expenditures, three specifications of expenditures were used. The primary measure of expenditures was relative changes in expenditures transformed into log-ratio. Under the log-ratio approach positive values indicate increased expenditures, and negative values indicate decreased expenditures. Other measures included logged expenditures (Year 3) derived after BMI changes were measured and relative changes in healthcare expenditures (i.e. percent change in expenditures) grouped into (1) no change; (2) greater than 10% decline; (3) greater than 10% increase and (4) minimal variations.;Results. Only a small fraction of the elderly experienced weight loss as measured by changes in BMI: Of 10,698 individuals, 9% experienced BMI loss (N=982) and 8.2% experienced BMI gain (N=867). Subgroup differences in BMI changes were noted: females were less likely than males to experience BMI loss or BMI gain [AOR 0.81, 95% CI 0.68-0.97; AOR 0.73 95%CI 0.60-0.90 ]. Increased age (80 + years) decreased the likelihood of BMI loss or BMI gain as compared to individuals 65-69 years [AOR 0.57, 95%CI 0.45-0.73; AOR 0.40 95%CI 0.31-0.52]; individuals older than 80 years were the only age group with increased risk of staying underweight/other.;After controlling for all the independent variables measured in this study, results from OLS regression for short-term logged expenditures revealed that compared to persons who stayed in normal BMI group, individuals with BMI loss had outpatient expenditures that were 23% higher. Compared to individuals who belonged to stayed normal BMI group, individuals with BMI gain had total expenditures that were 11% higher, outpatient expenditures that were 25% higher, and other expenditures that were 20% higher (p<0.05).;OLS regressions on log-ratio of expenditures suggested that when compared to individuals who stayed in normal BMI group, individuals who experienced BMI loss had significantly lower inpatient expenditures (beta = -0.54). When compared to individuals who stayed in normal BMI group, individuals with BMI gain significantly higher outpatient expenditures (beta = 0.172). Comorbid mental illness did not substantially alter the magnitude or direction of association between BMI and changes in expenditures in the population studied.;Conclusions/implications. Obesity has become an epidemic affecting all ages including the elderly, and is associated with increased morbidity, mortality and healthcare expenditures. Previous studies have focused primarily on the effects of weight loss on healthcare expenditures and have several limitations: The current study explored how changes in BMI affect a variety of healthcare expenditures within a Medicare population and additionally how comorbid mental illness impacts this relationship.;The current findings highlight the importance of maintaining normal weight and avoiding weight fluctuations. In light of the increased expenditures due to overweight and obesity, and the positive association between increasing BMI values and healthcare expenditures in the elderly, having a stable BMI is necessary to reduce healthcare costs. Collectively, findings from the current study emphasize the need for preventing overweight and obesity rather than treating these conditions and their negative effects. In this context, weight management and wellness programs that include nutrition and physical activity need to be an integral part of health promotion efforts for all individuals including the elderly. (Abstract shortened by UMI.).