Effectiveness and health care costs of collaborative care among depressed older adults with and without symptoms of posttraumatic stress disorder

Background: Depressed patients with comorbid posttraumatic stress disorder (PTSD) are more functionally impaired and may take longer to respond to depression treatment than patients without PTSD. Objective: To examine the effect of PTSD symptoms on depression severity, treatment response, and health care costs. Setting: 18 primary care clinics from 8 health care organizations in 5 states. Study Population: A total of 1801 patients aged 60 years or older with major depression or dysthymia were randomized to IMPACT collaborative care or usual care. The study included 191 (10.6%) depressed adults who screened positive for PTSD. Methods: Depression severity, assessed by the Hopkins Depression Symptom Checklist, was used to estimate depression-free days (DFDs) over 24 months. Total health care costs included inpatient, outpatient, and pharmacy costs. Results: PTSD+ patients had higher depression severity than PTSD- patients at baseline. PTSD+ patients had fewer DFDs than PTSD- patients over 2 years (302 vs. 321 DFDs), but was not significant (p=0.28). Total costs for PTSD+ depressed patients did not differ greatly from PTSD- patients ($14738 vs. $15961; p=0.44). PTSD+ patients benefited from the collaborative care intervention almost as much as PTSD- patients (gaining 9 fewer DFDs compared to usual care; p=0.79). Conclusion: PTSD+ depressed older adults were more depressed at baseline and gained DFDs from collaborative care (compared to usual care) similar to PTSD- patients. Collaborative care did not significantly effect overall costs in either group.