Longitudinal Effects of Depression on Health Care Expenditures among Older Adults

Purpose: With a high prevalence of depression among older adults, depression in older adults has been recognized as a significant public health concern. Previous studies have shown that individuals with depression incur higher health care costs than their counterparts without depression. Expanding previous cross-sectional studies, this study examined whether having depression among older adults is associated with an increase in health care expenditures during the following year, after controlling for other service use related variables selected according to the Andersen model.

Methods: This longitudinal study is based on a secondary analysis of the Medical Expenditure Panel Survey (MEPS; Panel 9, 2004-2005) for a nationally representative sample of 1,510 older adults aged 65 or older in 2004. In addition to descriptive analyses, OLS regressions were conducted with the survey procedures of STATA to account for the complex sampling design. Seven different OLS models were run for expenditures in different types of health care during 2005: total health care expenditures, office based visits, hospital outpatient visits, ER visits, inpatient hospital stays, home health care, and prescription medicines. Self-reported depression status during 2004 (year 1) and other medical conditions during 2005 (year 2), which were all matched to ICD-9 codes, were included as a major predictor and control variables in those models.

Results: Over 8.7% of older adults reported depression in 2004. Bivariate analyses indicate that older adults with depression had much higher total health care expenditures in the following year than their counterparts ($14,479 vs. $8,568; p=0.005). The difference remained significant in the OLS model (b=.28; p=.03) after controlling for health care needs and enabling factors during 2005 (perceived health status; 12 health conditions; # of bed days; income; insurance status); and predisposing factors (gender, age, education, and marital status). In terms of the type of health care, depressed older adults had higher levels of expenditures in office-based doctor visits (b=0.55; p<.0001) and prescription drugs (b=.49; p=.0002).

Implications: The results indicate that depression is associated with a longer-term increase in health care expenditures even after controlling for other health conditions and enabling factors among older adults. Further studies are needed to decide whether the increased expenditures associated with depression reflect adequate detection and treatment of depression among older adults or whether they reflect the adverse effects of untreated depression on older adults' comorbid health conditions and the effectiveness of services they receive.