Pain limits the effectiveness of collaborative care for depression.

OBJECTIVE: To ascertain the effects of baseline pain on depression outcomes in a collaborative care treatment trial of depression for older adults.

METHODS: A secondary data analysis of 1,801 depressed older adults in the Improving Mood: Providing Access to Collaborative Treatment trial, comparing groups with no/low and high baseline pain using two pain interference variables. The primary outcome was a 50% reduction in depression score at 12 months. Analyses were performed separately for usual care and intervention groups, then examined for interactions.

RESULTS: In the treatment-as-usual group, there was no significant association of baseline pain status with depression outcomes. In the intervention group, higher pain interference was significantly associated with worse depression response: 48.9% of those with no/low pain interference achieved a depression response, compared with 37.4% of those with high pain (chi2 = 12.27, df = 1, p = 0.001). Arthritis pain interference showed a similar association (chi2 = 4.04, df = 1, p = 0.044). Controlling for sociodemographic and baseline characteristics did not diminish this association. A significant interaction effect on depression response was found between pain interference and the intervention, suggesting that higher pain differentially impairs depression response in collaborative care compared to usual care.

CONCLUSION: A collaborative care intervention was significantly more successful in older adults with less pain. Pain may be an important barrier to improvement of depression and attending to pain might produce better depression outcomes.