Burning issues in the meta-analysis of pharmaceutical trials for depression

Exercise as antidepressant treatment: Time for the transition from trials to clinic?

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The International College of Neuropsychopharmacology (CINP) Treatment Guidelines for Bipolar Disorder in Adults (CINP-BD-2017), Part 1: Background and Methods of the Development of Guidelines

BACKGROUND

This paper includes a short description of the important clinical aspects of Bipolar Disorder with emphasis on issues that are important for the therapeutic considerations, including mixed and psychotic features, predominant polarity, and rapid cycling as well as comorbidity.

METHODS

The workgroup performed a review and critical analysis of the literature concerning grading methods and methods for the development of guidelines.

RESULTS

The workgroup arrived at a consensus to base the development of the guideline on randomized controlled trials and related meta-analyses alone in order to follow a strict evidence-based approach. A critical analysis of the existing methods for the grading of treatment options was followed by the development of a new grading method to arrive at efficacy and recommendation levels after the analysis of 32 distinct scenarios of available data for a given treatment option.

CONCLUSION

The current paper reports details on the design, method, and process for the development of CINP guidelines for the treatment of Bipolar Disorder. The rationale and the method with which all data and opinions are combined in order to produce an evidence-based operationalized but also user-friendly guideline and a specific algorithm are described in detail in this paper.

Fewer study participants needed to demonstrate superior antidepressant efficacy when using the Hamilton melancholia subscale (HAM-D₆) as outcome measure

BACKGROUND

In the development of new antidepressant treatments, the failed study has unfortunately become a prevalent problem. The number of failed studies could probably be reduced significantly by applying more informative outcome measures. Previous studies have indicated that the 6-item melancholia subscale (HAM-D6) of the 17-item Hamilton Depression Rating Scale (HAM-D17) may be more informative than other scales, due to its superior psychometric properties. In the present study we investigated whether the HAM-D6 had higher informativeness than the HAM-D17 based on data from a randomized placebo-controlled trial (RCT) testing the effect of erythropoietin (EPO) as augmentation therapy in patients with treatment-resistant depression.

METHODS

We assessed the scalability (Mokken analysis of unidimensionality), responsiveness (item responsiveness analysis) and ability to show drug-placebo separation (estimation of sample size needed to detect statistically significant difference between EPO and placebo) of the HAM-D6 and the HAM-D17.

RESULTS

The HAM-D6 demonstrated higher scalability, higher responsiveness, and better drug-placebo separation compared to the HAM-D17. As a consequence, only 39 participants per group would be required to detect a statistically significant difference between EPO and placebo when using the HAM-D6 as outcome measure, whereas the required group size for HAM-D17 would be 146 participants.

LIMITATIONS

The EPO RCT was not originally designed to investigate the research questions addressed in this study.

CONCLUSIONS

Both for ethical and financial reasons it is of interest to minimize the number of participants in clinical trials. Therefore, we suggest employing the HAM-D6 as outcome measure in clinical trials of depression.

Modelling the cost-effectiveness of pharmacotherapy compared with cognitive-behavioural therapy and combination therapy for the treatment of moderate to severe depression in the UK

BACKGROUND

The National Institute of Health and Care Excellence (NICE) in England and Wales recommends the combination of pharmacotherapy and psychotherapy for the treatment of moderate to severe depression. However, the cost-effectiveness analysis on which these recommendations are based has not included psychotherapy as monotherapy as a potential option. For this reason, we aimed to update, augment and refine the existing economic evaluation.

METHOD

We constructed a decision analytic model with a 27-month time horizon. We compared pharmacotherapy with cognitive-behavioural therapy (CBT) and combination treatment for moderate to severe depression in secondary care from a healthcare service perspective. We reviewed the literature to identify relevant evidence and, where possible, synthesized evidence from clinical trials in a meta-analysis to inform model parameters.

RESULTS

The model suggested that CBT as monotherapy was most likely to be the most cost-effective treatment option above a threshold of £ 22,000 per quality-adjusted life year (QALY). It dominated combination treatment and had an incremental cost-effectiveness ratio of £ 20,039 per QALY compared with pharmacotherapy. There was significant decision uncertainty in the probabilistic and deterministic sensitivity analyses.

CONCLUSIONS

Contrary to previous NICE guidance, the results indicated that even for those patients for whom pharmacotherapy is acceptable, CBT as monotherapy may be a cost-effective treatment option. However, this conclusion was based on a limited evidence base, particularly for combination treatment. In addition, this evidence cannot easily be transferred to a primary care setting.

Re-examining the role of benzodiazepines in the treatment of schizophrenia: a systematic review

BACKGROUND

Benzodiazepine prescribing for schizophrenia occurs in clinical practice and antipsychotic trials. This review examined the clinical outcomes for benzodiazepines in schizophrenia.

METHOD

A systematic search identified randomised controlled trials that evaluated benzodiazepines in comparison with placebo or antipsychotics, and also as adjuncts to antipsychotics. Relevant clinical outcome data was extracted.

RESULTS

Twenty six studies were included with some reporting multiple comparisons. Seven short-term studies compared benzodiazepines with placebo: benzodiazepine superiority was found in two out of five studies for global improvements and two out of four studies for psychiatric/behavioural outcomes. Eleven studies compared benzodiazepines with first-generation antipsychotics (FGAs): four out of nine studies (including two long-term studies) reported greater global improvements for antipsychotics; four out of five studies showed no treatment differences for psychiatric/behavioural outcomes. Fourteen studies compared benzodiazepines (as adjunct to antipsychotics) vs antipsychotics alone (mostly FGAs); benzodiazepine superiority was found for global improvement in one out of eight studies and inferiority in two out of eight short-term studies whereas superiority was found for psychiatric/behavioural outcomes in three out of 12 short-term studies and inferiority in three out of 12 studies.

CONCLUSION

Benzodiazepine superiority over placebo was found for global, psychiatric and behavioural outcomes, but inferiority to antipsychotics on longer-term global outcomes. Conflicting evidence exists regarding the addition of benzodiazepines to antipsychotics; thus the use of benzodiazepines in clinical practice and antipsychotic trials should be limited.

From Randomized Controlled Trials of Antidepressant Drugs to the Meta-Analytic Synthesis of Evidence: Methodological Aspects Lead to Discrepant Findings

During the last decade, several meta-analytic studies employing different methodological approaches have had inconsistent conclusions regarding antidepressant efficacy. Herein, we aim to comment on methodological aspects that may have contributed to disparate findings. We initially discuss methodological inconsistencies and limitations related to the conduct of individual antidepressant randomized controlled trials (RCTs), including differences in allocated samples, limitations of psychometric scales, possible explanations for the heightened placebo response rates in antidepressant RCTs across the past two decades as well as the reporting of conflicts of interest. In the second part of this article, we briefly describe the various meta-analyses techniques (e.g., simple random effects meta-analysis and network meta-analysis) and the application of these methods to synthesize evidence related to antidepressant efficacy. Recently published antidepressant metaanalyses often provide discrepant results and similar results often lead to different interpretations. Finally, we propose strategies to improve methodology considering real-world clinical scenarios.