Incremental cost-effectiveness of a collaborative care intervention for panic disorder.

BACKGROUND: Panic disorder is a prevalent, often disabling, disorder among primary-care patients, but there are large gaps in quality of treatment in primary care. This study describes the incremental cost-effectiveness of a combined cognitive behavioral therapy (CBT) and pharmacotherapy intervention for patients with panic disorder versus usual primary-care treatment.

METHOD: This randomized control trial recruited 232 primary-care patients meeting DSM-IV criteria for panic disorder from March 2000 to March 2002 from six primary-care clinics from university-affiliated clinics at the University of Washington (Seattle) and University of California (Los Angeles and San Diego). Patients were randomly assigned to receive either treatment as usual or a combined CBT and pharmacotherapy intervention for panic disorder delivered in primary care by a mental health therapist. Intervention patients had up to six sessions of CBT modified for the primary-care setting in the first 12 weeks, and up to six telephone follow-ups over the next 9 months. The primary outcome variables were total out-patient costs, anxiety-free days (AFDs) and quality adjusted life-years (QALYs).

RESULTS: Relative to usual care, intervention patients experienced 60.4 [95% confidence interval (CI) 42.9-77.9] more AFDs over a 12-month period. Total incremental out-patient costs were 492 US dollars higher (95% CI 236-747 US dollars ) in intervention versus usual care patients with a cost per additional AFD of 8.40 US dollars (95% CI 2.80-14.0 US dollars ) and a cost per QALY ranging from 14,158 US dollars (95% CI 6,791-21,496 US dollars ) to 24,776 US dollars (95% CI 11,885-37,618 US dollars ). The cost per QALY estimate is well within the range of other commonly accepted medical interventions such as statin use and treatment of hypertension.

CONCLUSIONS: The combined CBT and pharmacotherapy intervention was associated with a robust clinical improvement compared to usual care with a moderate increase in ambulatory costs.