The Relationships Among Depression, Physical Health Conditions and Healthcare Expenditures for Younger and Older Americans

Background: Individuals with depression and individuals with chronic health conditions incur higher healthcare costs than their counterparts without such conditions. Accordingly, it is assumed that people with depression and co-morbid health conditions may have higher healthcare expenditures when compared with those who have physical health conditions but are not clinically depressed. However, little is known about the extent depression adds to the costs of treatment for physical health conditions. The purpose of the study was to examine the extent to which depression in conjunction with a physical health problem is associated with an increase in healthcare expenditures. We examined the direct and indirect effects (through physical co-morbidity) of depression on healthcare expenditures. In addition, to inform targeted policies and practices, this mediating relationship was tested by different age groups (i.e., younger vs. older adults; moderated mediation).

Methods: The 2007 Medical Expenditure Panel Survey (MEPS) provided the data for this study. The nationally representative sample consisted of 16,384 individuals including 13,207 younger adults (18-64) and 3,177 older adults (65+). Self-reported depression status matched to ICD-9 codes allowed for identification of individuals with clinical depression. Other medical conditions were also identified through ICD-9 codes provided by the MEPS and scores from the Charlson Comorbidity Index provided an indication of the severity of these medical conditions. In addition to univariate and bivariate statistics provided, structural equation modeling (SEM) was employed to examine the moderated mediation effects using M-plus software. Socio-demographic and service related control variables were included in the models.

Results: Approximately 12% of the sample was identified as having clinical depression (n = 1,937). Bivariate tests indicated that people with depression had higher total healthcare expenditures ($9,310) when compared to those without depression ($4,953; t = -13.17, p < 0.001). Among people with depression, those with health problems had higher total healthcare expenditures ($15,635) when compared to those without co-morbid medical conditions ($6,782; t = -10.19, p < 0.001). The SEMs for both age groups indicated that people with depression had higher healthcare expenditures compared to people without depression (i.e., depression had a direct effect on expenditures). Also, depression was associated with higher levels of healthcare expenditures through the presence of co-morbid health conditions (i.e., an indirect effect; b = 0.017 for younger people and b = 0.032 for older people). In other words, people with depression were more likely to have co-morbid health condition and having co-morbid health conditions tended to increase healthcare expenditures. These indirect effects of depression on expenditures through co-morbid medical conditions were about twice as great among older adults than among younger adults.

Conclusions and implications: Findings suggest that proper detection and treatment of depression is beneficial in reducing overall healthcare expenditures, especially among older adults. Late-life depression is a treatable condition and the treatment and detection of geriatric depression needs to be a collaborative effort among a wide-range of professionals including health and social service providers.