CRD summary

This review found that continuation of antidepressant treatment following an acute response reduced relapses in anxiety disorders, but the relative efficacy of continuation treatment appeared to vary by disorder. This was a well-conducted review and the authors' conclusions are likely to be reliable.

Authors' objectives

To determine the efficacy of continuation antidepressant treatment in preventing relapse in anxiety disorders.

Searching

MEDLINE and EMBASE were searched from inception to August 2008. Search terms were reported. Reference lists of retrieved studies, electronic search tools, clinical trials website, and pharmaceutical trials registers were searched for additional studies. The review was restricted to English language studies.

Study selection

Randomised controlled trials (RCT) that assigned patients who had responded to an initial course of acute drug therapy for DSM (Diagnostic and Statistical Manual of mental disorders)-defined anxiety disorders, to continue on blinded active drug or to be switched to blinded placebo, were eligible for inclusion. Eligible trials had to report rates of subsequent relapse across trial arms. Trials also had to use a double-blind parallel group design and assess monoamine reuptake inhibiting antidepressants at labelled doses. Patients with comorbid mood disorders were excluded.

Most included trials assessed selective serotonin reuptake inhibitors. All studies were conducted in adults with panic disorder, generalised anxiety disorder, social phobia, post-traumatic stress disorder, and obsessive-compulsive disorder. Intervention duration prior to randomisation ranged from eight to 52 weeks; duration of post-randomisation also ranged from eight to 52 weeks. Trial characteristics were available in a supplementary online table.

Two reviewers independently assessed studies for inclusion; disagreements were resolved through consensus.

Assessment of study quality

Two reviewers independently assessed trial quality using the Cochrane Collaboration's Risk of Bias Tool. Disagreements were resolved through consensus.

Data extraction

Two reviewers independently extracted data on the number of patients randomised to each group and the number of relapses in each group during the continuation phrase of the study. These data were used to calculate odds ratios (OR), relative risks (RR), risk differences, and number-needed-to-treat together with 95% confidence intervals (CI). If multiple relapse definitions or time points were provided, only those specified as primary were included. Disagreements were resolved through consensus.

Methods of synthesis

Summary estimates together with 95% confidence intervals were calculated using the Mantel-Haenszel fixed-effects model, grouped according to anxiety disorder. Statistical heterogeneity was assessed using the X² and I² statistics. Summary estimates were compared using ANOVA (analysis of variance) for ranked clusters of anxiety disorders. Summary estimates by anxiety disorders were also plotted in a star graph. Forest plots were used to display individual trial results and summary results.

Results of the review

Twenty two RCTs were included in the review (n=4,147 patients).

Continuation antidepressant treatment showed significant beneficial effects for all anxiety disorders assessed, which included: generalised anxiety disorder (RR 0.31, 95% CI 0.25 to 0.38; three RCTS; n=1,342 patients), social phobia (RR 0.39, 95% CI 0.30 to 0.49; four RCTs; n=760 patients), post-traumatic stress disorder (RR 0.35, 95% CI 0.19 to 0.62; three RCTs; n=272 patients), panic disorder (RR 0.44, 95% CI: 0.32 to 0.60; six RCTs; n=796 patients), and obsessive compulsive disorder (RR 0.54, 95% CI 0.45 to 0.66; six RCTs; n=951 patients).

The numbers-needed-to-treat ranged from 3 to 7 across anxiety disorders.

There was no evidence of heterogeneity for any of the anxiety disorders.

Authors' conclusions

This meta-analysis showed the importance of continuation of antidepressant treatment following acute response in all five anxiety disorders, but the relative efficacy of continuation antidepressant treatment appeared to vary by disorder.

CRD commentary

The review addressed a focused question, supported by clearly defined inclusion criteria. The literature search was appropriate and included some attempts to locate unpublished studies, but publication bias was not assessed. The review was restricted to English language studies, so there was a possibility of language bias. Appropriate steps were taken to minimise bias and errors at all stages of the review process.

Relevant trial details were summarised in a supplementary online table. An appropriate tool was used to assess trial quality, but the results of this assessment were not reported. The methods used to pool data were appropriate and the results were clearly reported in the text, tables and graphs.

The authors' conclusions were supported by the data presented and are likely to be reliable.

The authors disclosed that they all worked for Pfizer (the manufacturers of some of the antidepressants used in the included trials) while this analysis was performed.

Implications of the review for practice and research

Practice: The authors stated that this meta-analysis confirms the importance of antidepressant continuation treatment following acute response in all five anxiety disorders.

Research: The authors stated that further work is required to determine if there are benefits of continuation treatment with other pharmacological classes of anti-anxiety treatment, and to determine the optimal duration for continuation treatment.

Funding

Pfizer, Inc.

Bibliographic details

Donovan MR, Glue P, Kolluri S, Emir B. Comparative efficacy of antidepressants in preventing relapse in anxiety disorders: a meta-analysis. Journal of Affective Disorders 2009; 123(1-3): 9-16. [PubMed: 19616306]

Original Paper URL

http://dx.doi.org/10.1016/j.jad.2009.06.021

Indexing Status

Subject indexing assigned by NLM

MeSH

Adult; Antidepressive Agents /therapeutic use; Anxiety Disorders /drug therapy /psychology; Double-Blind Method; Humans; Obsessive-Compulsive Disorder /drug therapy /psychology; Panic Disorder /drug therapy /psychology; Personality Assessment; Phobic Disorders /drug therapy /psychology; Randomized Controlled Trials as Topic; Recurrence /prevention & control; Stress Disorders, Post-Traumatic /drug therapy /psychology; Treatment Outcome

AccessionNumber

12009108789

Database entry date

14/07/2010

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.