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Authors' reply

Published online by Cambridge University Press:  02 January 2018

Mario álvarez-Jiménez
Affiliation:
ORYGEN Research Centre, University of Melbourne, Australia, and University Hospital ‘Marqués de Valdecilla’, Department of Psychiatry, University of Cantabria School of Medicine, Santander, Spain. Email: malvarez@unimelb.edu.au
Sarah E. Hetrick
Affiliation:
ORYGEN Research Centre, University of Melbourne, Australia
César González-Blanch
Affiliation:
University Hospital ‘Marqués de Valdecilla’, Department of Psychiatry, University of Cantabria School of Medicine, Santander, Spain
John F. Gleeson
Affiliation:
ORYGEN Research Centre, and Department of Psychiatry, University of Melbourne, and NorthWestern Mental Health Programme, Melbourne, Australia
Patrick D. McGorry
Affiliation:
ORYGEN Research Centre, University of Melbourne, Australia
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Abstract

Type
Columns
Copyright
Copyright © Royal College of Psychiatrists 2009 

We would like to thank George et al for their comments. However, we believe that some clarification is needed regarding the outcomes and procedures of our meta-analysis.

First, we agree that percentage of weight gain is a more appropriate measure to assess weight gain compared with body weight change. In fact, somewhere else we have pointed to ‘the importance of reporting percentage of weight gain, as absolute body weight changes may be deceptive, concealing the real extent of this side effect on those who experience weight gain’. Reference Álvarez-Jiménez, González-Blanch, Crespo-Facorro, Hetrick, Rodríguez-Sánchez and Pérez-Iglesias1 To put it more simply, research shows that up to 80% of individuals being treated with antipsychotics suffer significant gain in body weight. As a result, patients taking antipsychotics are more likely to gain 20 kg than they are to lose 20 kg. Indeed, weight-management interventions do not usually produce weight loss but they attenuate antipsychotic-induced weight gain. Reference Eálvarez-Jiménez, Hetrick, González-Blanch, Gleeson and McGorry2 For these reasons, data on weight change is unlikely to overestimate the effectiveness of weight management interventions as George et al contend. To illustrate this further, in a previous randomised controlled trial (RCT) of weight-management interventions we assessed the proportion of patients that gained more than 7% of their baseline body weight. Patients in the control group gained 6.9 kg compared with 3.9 kg in the intervention group. These absolute gains were translated into 78.8% in the control group increasing their baseline weight by more than 7% v. 39.9% in the intervention group. Reference Álvarez-Jiménez, González-Blanch, Vázquez-Barquero, Pérez-Iglesias, Martínez-García and Pérez-Pardal3

George et al also commented on the quality of the included trials as a potential threat to the reliability of the results. First, it should be pointed out that only RCTs were included – in three of them we were able to pool relevant data with the help of the authors. Second, we performed several sensitivity analyses to determine the robustness of our findings to the exclusion of low-quality trials and exclusion of small trials. Reference Egger, Smith and Phillips4 The exclusion of these studies affected the overall effect size and confidence intervals only marginally. Importantly, there was notable consistency across all study estimates, which was reflected in the robustness of the findings across analytic methods. Thus, our findings are unlikely to be biased by these issues.

After examining all the available evidence, it is now possible to conclude that large-scale pragmatic trials with longer follow-up are needed to make further progress in this area as George et al state.

References

1 Álvarez-Jiménez, M, González-Blanch, C, Crespo-Facorro, B, Hetrick, S, Rodríguez-Sánchez, JM, Pérez-Iglesias, R, et al. Antipsychotic-induced weight gain in chronic and first-episode psychotic disorders: a systematic critical reappraisal. CNS Drugs 2008; 22: 547–62.CrossRefGoogle ScholarPubMed
2 Eálvarez-Jiménez, M, Hetrick, SE, González-Blanch, C, Gleeson, JF, McGorry, PD. Non-pharmacological management of antipsychotic-induced weight gain: systematic review and meta-analysis of randomised controlled trials. Br J Psychiatry 2008; 193: 101–7.Google Scholar
3 Álvarez-Jiménez, M, González-Blanch, C, Vázquez-Barquero, JL, Pérez-Iglesias, R, Martínez-García, O, Pérez-Pardal, T, et al. Attenuation of antipsychotic-induced weight gain with early behavioral intervention in drug-naive first-episode psychosis patients. A randomized controlled trial. J Clin Psychiatry 2006; 67: 1253–60.Google Scholar
4 Egger, M, Smith, GD, Phillips, AN. Meta-analysis: principles and procedures. BMJ 1997; 315: 1533–7.Google Scholar
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