Evaluation of a practice team-supported exposure training for patients with panic disorder with or without agoraphobia in primary care - study protocol of a cluster randomised controlled superiority trial

Background: Panic disorder and agoraphobia are debilitating and frequently comorbid anxiety disorders. A large number of patients with these conditions are treated by general practitioners in primary care. Cognitive behavioural exposure exercises have been shown to be effective in reducing anxiety symptoms. Practice team-based case management can improve clinical outcomes for patients with chronic diseases in primary care. The present study compares a practice team-supported, self-managed exposure programme for patients with panic disorder with or without agoraphobia in small general practices to usual care in terms of clinical efficacy and cost-effectiveness. Methods/Design: This is a cluster randomised controlled superiority trial with a two-arm parallel group design. General practices represent the units of randomisation. General practitioners recruit adult patients with panic disorder with or without agoraphobia according to the International Classification of Diseases, version 10 (ICD-10). In the intervention group, patients receive cognitive behaviour therapy-oriented psychoeducation and instructions to self-managed exposure exercises in four manual-based appointments with the general practitioner. A trained health care assistant from the practice team delivers case management and is continuously monitoring symptoms and treatment progress in ten protocol-based telephone contacts with patients. In the control group, patients receive usual care from general practitioners. Outcomes are measured at baseline (T0), at follow-up after six months (T1), and at follow-up after twelve months (T2). The primary outcome is clinical severity of anxiety of patients as measured by the Beck Anxiety Inventory (BAI). To detect a standardised effect size of 0.35 at T1, 222 patients from 37 general practices are included in each group. Secondary outcomes include anxiety-related clinical parameters and health-economic costs.