Context: Depression is a pervasive and costly medical issue, but little is known about predictors of response to usual care in primary care.
Objective: Examine what patient characteristics are associated with poor response
Design: Observational
Setting: 82 primary care clinics across Minnesota
Participants: 517 patients enrolled in DIAMOND clinics
Interventions: Usual (pre-implementation) care for depression
Outcome Assessment: Partial response and remission via PHQ-9 at 6 months.
Results: Participants tended to be women, caucasian, and employed. At baseline, 59% had mild depression, 30% moderate, and 11% severe. All patients received antidepressants and 31% received therapy or psychiatric referral. Overall, depression had not improved for 54% of patients at six months. Patients were significantly less likely to experience a response if they were unemployed (OR=0.6, 95%CI: 0.4-0.8, p=0.003), had lower household incomes(OR=0.6, 95%CI:0.4-0.8, p=0.004), had non-commercial health insurance (OR=0.7, 95%CI:0.5-1.0, p=0.04), had poor-to-fair self-reported physical health (OR=0.5, 95%CI:0.3-0.7, p<0.001), or who had been treated for depression for more than 4 weeks at baseline (OR=0.6, 95%CI:0.4-0.9, p=0.005).
Conclusions: The majority of patients do not achieve response or remission when treated with usual care for depression for primary care. Predictors of poorer response and remission were unemployment, non-commercial health insurance, lower income, poorer health status, and greater length of time of current treatment. Providers and care systems may be able to improve patient outcomes while limiting expenditures by focusing more costly interventions for depression on those patients least likely to respond to usual care of depression.