Effect of Usual Source of Care on Depression among Medicare Beneficiaries: An Application of a Simultaneous-Equations Model

Objective. To investigate whether having a usual source of care (USOC) resulted in lower depression prevalence among the elderly. Data Sources. The 2001-2003 Medicare Current Beneficiaries Survey and 2002 Area Resource File. Study Design. Twenty thousand four hundred and fifty-five community-dwelling person-years were identified for respondents aged 651, covered by both Medicare Parts A and B in Medicare fee-for-service for a full year. USOC was defined by the question "Is there a particular medical person or a clinic you usually go to when you are sick or for advice about your health?'' Ambulatory care use (ACU) was defined by having at least one physician office visit and/or hospital outpatient visit using Medicare claims. Depression was identified by a two-item screen (sadness and/or anhedonia). All measures were for the past 12 months. A simultaneous-equations (trivariate probit) model was estimated, adjusted for sampling weights and study design effects. Principal Findings. Based on the simultaneous-equations model, USOC is associated with 3.8 percent lower probability of having depression symptoms (p=.03). Also, it had a positive effect on having any ACU (p<.001). Having any ACU had no statistically significant effect on depression (p=.96). Conclusions. USOC was associated with lower depression prevalence and higher realized access (ACU) among community-dwelling Medicare beneficiaries.