PubMed2005
BACKGROUND: The economic burden of depression has been documented, but the role of comorbid conditions is unclear. Depression and comorbid pain are particularly common, are associated with worse clinical outcomes and require different care than "pure'' depression. Does this comorbidity account for a large share of the adverse social outcomes attributed to depression? AIMS OF STUDY: We analyzed the relationship between depression and comorbid pain, and labor market, financial, insurance and disability outcomes among Americans aged 55-65. METHODS: Cross-sectional data were used from Wave 3 of the Health and Retirement Survey, a nationally representative sample of individuals aged 55-65 surveyed in 1996. Multivariate regression analyses, controlling for socio-demographics and chronic health conditions, estimated the associations between depression and pain, and economic outcomes. Outcomes included: employment and retirement status, household income, total medical expenditures, government health insurance, social security, limitations in activities of daily living (ADLs), and health limitations affecting work. Primary explanatory variables included the presence of severe pain, mild/moderate pain, or absence of pain, with or without depression. RESULTS: Compared to depression alone, depression and comorbid pain was associated with worse labor market (non-employment, retirement), financial (total medical expenditures), insurance (government insurance, social security) and disability outcomes (limitations in ADLs, health limitations affecting work), after covariate adjustment (p <or= 0.01, except retirement with p < 0.1). Findings were even more disparate as level of pain severity increased. The simulated results showed that the magnitudes of the adverse effects were attributed disproportionally to individuals with comorbid pain and depression versus "pure'' depression. Of those with depression, 51% had comorbid pain. Yet, this subgroup of depressed individuals accounted for 59% of those not employed, 61% of those with government health insurance, 79% of those with limitations in ADLs, and 72% of those with health limitations affecting work. DISCUSSION AND LIMITATION: Depression with comorbid pain, not depression alone was responsible for a large part of the higher economic burden associated with depression. The study is limited by self-reported measures of pain, depression, and outcomes. It is cross-sectional and cannot identify causal effects of depression with pain. These findings may not be generalizable to other age groups. IMPLICATIONS FOR HEALTH CARE PROVISION AND USE: The depressed with comorbid pain appear to experience greater burden through increased costs and worse functioning and may require different management than those with depression alone. The depressed with comorbid pain may benefit from treatment practices and guidelines that address the duality of these conditions throughout the process of care. IMPLICATION FOR HEALTH POLICIES: The depressed with comorbid pain were more likely to receive government support than depression alone. Given the central role of employer-sponsored health insurance in the U.S., they may have worse access to health care because they leave employment or retire earlier. With the evolving state of Medicare, broad formulary access to mental health treatments might be considered. IMPLICATIONS FOR FURTHER RESEARCH: Further research should focus on causality of depression and comorbid pain on economic outcomes. Depression research should consider the heterogeneity of this disorder in outcomes assessment.