Depression and comorbid pain as predictors of disability, employment, insurance status, and health care costs.

OBJECTIVE: Individuals with depression commonly experience pain with unclear pathology. This study examined depression and comorbid pain and associated outcomes over six years in a nationally representative cohort of older Americans.
METHODS: The Health and Retirement Study began in 1992 and follows 9,825 individuals between the ages of 50 and 61 years. The study reported here used data beginning in 1994 to contrast individuals with depression and those with depression plus comorbid pain. Regression models adjusted for differences in sociodemographic characteristics and health status.
RESULTS: Baseline (1994) data were available for 8,280 participants. At baseline, 65.2 percent reported that they did not have pain or depression, 8.1 percent had depression alone, 15.5 percent had mild or moderate pain alone, 2 percent had severe pain alone, 6.6 percent had depression plus mild or moderate pain, and 2.6 percent had depression plus severe pain. Compared with the group with no pain or depression, all the groups with depression, pain, or both had greater decrements in outcomes. Groups tended to have greater decrements in outcomes as levels of pain increased. Overall, no statistically significant differences were found between the groups with depression plus pain and their corresponding groups with pain alone. Two to six years after baseline, compared with participants with depression alone, those with severe pain or depression plus severe pain were more likely to experience new functional limitations and to have higher total health care expenditures. Compared with participants with depression alone, participants with depression plus severe pain were also more likely to lose employment and private health insurance.
CONCLUSIONS: Relative to depression alone, depression plus pain and pain alone (particularly severe pain) were associated with significant functional limitations and economic burdens.