Background: Collaborative care for depression is more effective in improving treatment outcomes than primary care physicians' (PCPs) usual care (UC). However, few trials of collaborative care have targeted anxiety.
Objective: To examine the impact and 12-month durability of a centralized, telephone-delivered, stepped collaborative care intervention (CC) for treating anxiety disorders across a network of primary care practices.
Design: Randomized controlled trial with blinded outcome assessments.
Participants: A total of 329 patients aged 18-64 referred by their PCPs in response to an electronic medical record (EMR) prompt. They include 250 highly anxious patients randomized to either CC or to UC, and 79 moderately anxious patients who were triaged to a watchful waiting (WW) cohort and later randomized if their conditions clinically deteriorated.
Intervention: Twelve months of telephone-delivered CC involving non-mental health professionals who provided patients with basic psycho-education, assessed preferences for guideline-based pharmacotherapy, monitored treatment responses, and informed PCPs of their patients' care preferences and progress via the EMR.
Main measures: Mental health-related quality of life ([HRQoL]; SF-36 MCS); secondary outcomes: anxiety (Hamilton Anxiety Rating Scale [SIGH-A], Panic Disorder Severity Scale) and mood (PHQ-9).
Key results: At 12-month follow-up, highly anxious patients randomized to CC reported improved mental HRQoL (effect size [ES]: 0.38 [95 % CI: 0.13-0.63]; P = 0.003), anxiety (SIGH-A ES: 0.30 [0.05-0.55]; P = 0.02), and mood (ES: 0.45 [0.19-0.71] P = 0.001) versus UC. These improvements were sustained for 12 months among African-Americans (ES: 0.70-1.14) and men (ES: 0.43-0.93). Of the 79 WW patients, 29 % met severity criteria for randomization, and regardless of treatment assignment, WW patients reported fewer anxiety and mood symptoms and better mental HRQoL over the full 24-month follow-up period than highly anxious patients who were randomized at baseline.
Conclusions: Telephone-delivered, centralized, stepped CC improves mental HRQoL, anxiety and mood symptoms. These improvements were durable and particularly evident among those most anxious at baseline, and among African-Americans and men.
Keywords: anxiety; clinical trial; collaborative care; depression; mental health; primary care.