Other predictors of poor response included unemployment and lower income. Conversely, younger age and milder baseline depression severity predicted better response.
The results point to a subset of patients who might be identified for more intensive services, including collaborative care, which can address general and psychiatric conditions, say researchers at several institutions.
“The take-away message of our study is that six-month rates of depression remission or response were only 47 percent in this large population of primary care patients receiving usual care, and those who self-rated their health as poor to fair or who were unemployed were significantly less likely to see their depression improve,” lead author Rebecca Rossom, M.D. (pictured above) of HealthPartners Institute, told Psychiatric News. “Collaborative care can be effective for depression; however, this model can be cost-prohibitive for some care systems. For those systems it would be more efficient to focus use of this model on patients who are more likely to have poor depression outcomes.”
Outcome data for 792 patients in 83 urban and rural primary care clinics across Minnesota were analyzed. Baseline and six-month data were collected between March 2008 and November 2010, prior to the implementation of collaborative care in these primary care clinics. Patients received usual care for depression in their primary care clinics; all received antidepressants for depression, and some patients were co-managed by psychotherapists or psychiatrists.
The primary outcome was remission or response, with remission defined as achieving a follow-up PHQ-9 score of 5 or less; response was defined as a follow-up PHQ-9 score that was at least 50 percent lower than the patient’s baseline score. A wide range of correlates to treatment response were examined.
At six months, 47% of patients achieved a combined outcome of remission (N=292) or response (N=83). Patients who reported fair or poor health were significantly less likely to experience depression remission or response compared with patients with good, very good, or excellent health. Patients who were unemployed or had lower income were also less likely to respond.
“Ideally, being better able to identify such predictors of poor depression outcomes may help clinics and care systems determine where limited but potentially effective intensive and evidence-based treatment resources for depression may be most helpful,” the researchers stated.
For related information, see the Psychiatric News article "Brain Area Activity Might Predict Depression Treatment Response."
(Image courtesy Rebecca Rossom, M.D.)