Antidepressant Utilization, Adherence, and Health Care Spending in the United States: The Case of MDD Patients 2000-2007

ObjectiveSelective serotonin reuptake inhibitors have been widely adopted in the US as the first-line treatment for major depressive disorder (MDD). This study attempted to understand how patient factors and antidepressant choice influenced medication adherence and associated health care expenditures.Study DesignA retrospective multiple-year cross-sectional study was conducted. This study used the 2004-2007 Medical Expenditure Panel Survey database; MDD patients who filled one or more prescriptions of antidepressants were extracted. Data were analyzed using weighted ordinary least squares regressions to examine MDD patient antidepressant adherence (measured by proportional days covered) and impacts of patient factors on associated health care expenditures.ResultsSociological factors such as patient ethnicity and health insurance status were associated with differential levels of antidepressant adherence and associated health expenditures. Hispanic ethnicity was associated with the lowest antidepressant adherence among all. Patients covered by insurance were associated with better proportional days covered and spent more on MDD-specific drugs compared with uninsured patients. Use of newer antidepressants such as selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors was associated with an increase in MDD-specific drug expenditure.ConclusionsDifferences in antidepressant adherence and health care spending across patient factors could have important policy implications for health disparity; certain patient populations may be at higher risk for inadequate health care.