BJOG Exchange
effectiveness of exercise for the prevention and treatment of antenatal depression: systematic review with meta-analysis. BJOG 2014;122:57–62. 3 Morris RK, Meller CH, Tamblyn J, Malin GM, Riley RD, Kilby MD, et al. Association and prediction of amniotic fluid measurements for adverse pregnancy outcome: systematic review and meta-analysis. BJOG 2014;121:686–99. 4 Wood S, Cooper S, Ross S. Does induction of labour increase the risk of caesarean section? A systematic review and meta-analysis of trials in women with intact membranes. BJOG 2014;121:674–85.
C Griffin School of Women’s and Infants’ Health, the University of Western Australia, King Edward Memorial Hospital, Bagot Road, Subiaco, WA, Australia Accepted 3 July 2014. DOI: 10.1111/1471-0528.13133
Authors’ reply Sir, We would like to thank Chris Griffin for his interest in our recent article. We agree that it is useful to consider the biological plausibility of an intervention when interpreting statistical findings from a study, but biological plausibility is not the only consideration. Moreover, there are a number of longstanding biological, psychological, and social mechanisms by which exercise is thought to reduce depression. Within the space allowed by the journal we were not able to explore all the potential mechanisms of exercise on depression, and we direct readers now to other articles that explain and critically appraise these mechanisms in detail.1–3 We should also remember that what is biologically plausible depends upon the biological knowledge of the day. As Sherlock Holmes advised Dr Watson, ‘when you have eliminated the impossible, whatever remains, however improbable, must be the truth’. n References 1 Daley AJ. Exercise and depression: a review of reviews. J Clin Psychol Med Settings 2008;15:140–7.
2 Ernst C, Olson AK, Pinel JPJ, Lam RW, Christie BR. Antidepressant effects of exercise: evidence for an adult-neurogenesis hypothesis? J Psychiatry Neurosci 2006;31:84–92. 3 Craft LL, Perna FM. The benefits of exercise for the clinically depressesd. Prim Care Companion J Clin Psychiatry 2004;6:104– 11.
A Daley, on behalf of the study authors Primary Care Clinical Sciences, University of Birmingham, Birmingham, UK Accepted 16 July 2014. DOI: 10.1111/1471-0528.13135
Author’s reply Sir, The multitude of studies within the published literature on amniotic fluid measurements and pregnancy outcome has resulted from biological plausibility, relating amniotic fluid production to fetal wellbeing. Our systematic review was designed to address the exact dilemma raised by Dr Griffin, namely whether there is a true association with abnormal amniotic fluid volume and adverse pregnancy outcome, but more importantly whether in the individual this test could be used to predict outcome. As we found this not to be the case, it was thus not appropriate to assess the use of this test any further in the clinical management pathway. The strengths of systematic reviews and meta-analyses are that they assess all the available evidence in a non-biased manner, with attention to detail of confounding factors and bias within individual studies, and with both qualitative and quantitative assessment. The importance of these techniques is highlighted by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance on reporting of systematic reviews and meta-analyses.1 We thus disagree with the statement that these techniques are ‘statistical gymnastics’. We agree with the statement that evidence-based medicine should be directed at answering the clinician’s diagnostic and management dilemmas. Thus once a test is found to be predic-
ª 2015 Royal College of Obstetricians and Gynaecologists
tive/accurate it is important to assess its use in the clinical management pathway, as highlighted in our review on the use of uterine artery Doppler for the prediction of pre-eclampsia.2 Here, we present evidence of accuracy, but also numbers needed to test and numbers needed to treat (using aspirin as an intervention), to allow the clinician and patient a clearer understanding of how the use of this investigation could affect their management. This we believe is the essence of evidence-based medicine. n References 1 Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group. preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med 2009;6: e1000097. 2 Cnossen JS, Morris RK, ter Riet G, Mol BW, van der Post JA, Coomarasamy A, et al. Use of uterine artery Doppler ultrasonography to predict pre-eclampsia and intrauterine growth restriction: a systematic review and bivariable meta-analysis. CMAJ 2008;178: 701–11.
RK Morris NIHR Clinical Lecturer in Maternal Fetal Medicine, Birmingham Centre for Women and Children’s Health, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham Women’s Hospital, Edgbaston, Birmingham, B15 2TG, UK Accepted 16 July 2014. DOI: 10.1111/1471-0528.13134
Authors’ reply Sir, Like the author of this letter, I too had read with interest the referenced essay in the British Medical Journal regarding the ‘crisis in Evidence Based Medicine’;1 however, I was unable to find any reference to the need to report ‘biological plausibility’ in a systematic review. Current guidelines for the reporting of metaanalysis (Preferred Reporting Items for Systematic Reviews and Meta-Analyses, PRISMA) do not mandate this either.2
591
Copyright of BJOG: An International Journal of Obstetrics & Gynaecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
effectiveness of exercise for the prevention and treatment of antenatal depression: systematic review with meta-analysis. BJOG 2014;122:57–62. 3 Morris RK, Meller CH, Tamblyn J, Malin GM, Riley RD, Kilby MD, et al. Association and prediction of amniotic fluid measurements for adverse pregnancy outcome: systematic review and meta-analysis. BJOG 2014;121:686–99. 4 Wood S, Cooper S, Ross S. Does induction of labour increase the risk of caesarean section? A systematic review and meta-analysis of trials in women with intact membranes. BJOG 2014;121:674–85.
C Griffin School of Women’s and Infants’ Health, the University of Western Australia, King Edward Memorial Hospital, Bagot Road, Subiaco, WA, Australia Accepted 3 July 2014. DOI: 10.1111/1471-0528.13133
Authors’ reply Sir, We would like to thank Chris Griffin for his interest in our recent article. We agree that it is useful to consider the biological plausibility of an intervention when interpreting statistical findings from a study, but biological plausibility is not the only consideration. Moreover, there are a number of longstanding biological, psychological, and social mechanisms by which exercise is thought to reduce depression. Within the space allowed by the journal we were not able to explore all the potential mechanisms of exercise on depression, and we direct readers now to other articles that explain and critically appraise these mechanisms in detail.1–3 We should also remember that what is biologically plausible depends upon the biological knowledge of the day. As Sherlock Holmes advised Dr Watson, ‘when you have eliminated the impossible, whatever remains, however improbable, must be the truth’. n References 1 Daley AJ. Exercise and depression: a review of reviews. J Clin Psychol Med Settings 2008;15:140–7.
2 Ernst C, Olson AK, Pinel JPJ, Lam RW, Christie BR. Antidepressant effects of exercise: evidence for an adult-neurogenesis hypothesis? J Psychiatry Neurosci 2006;31:84–92. 3 Craft LL, Perna FM. The benefits of exercise for the clinically depressesd. Prim Care Companion J Clin Psychiatry 2004;6:104– 11.
A Daley, on behalf of the study authors Primary Care Clinical Sciences, University of Birmingham, Birmingham, UK Accepted 16 July 2014. DOI: 10.1111/1471-0528.13135
Author’s reply Sir, The multitude of studies within the published literature on amniotic fluid measurements and pregnancy outcome has resulted from biological plausibility, relating amniotic fluid production to fetal wellbeing. Our systematic review was designed to address the exact dilemma raised by Dr Griffin, namely whether there is a true association with abnormal amniotic fluid volume and adverse pregnancy outcome, but more importantly whether in the individual this test could be used to predict outcome. As we found this not to be the case, it was thus not appropriate to assess the use of this test any further in the clinical management pathway. The strengths of systematic reviews and meta-analyses are that they assess all the available evidence in a non-biased manner, with attention to detail of confounding factors and bias within individual studies, and with both qualitative and quantitative assessment. The importance of these techniques is highlighted by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidance on reporting of systematic reviews and meta-analyses.1 We thus disagree with the statement that these techniques are ‘statistical gymnastics’. We agree with the statement that evidence-based medicine should be directed at answering the clinician’s diagnostic and management dilemmas. Thus once a test is found to be predic-
ª 2015 Royal College of Obstetricians and Gynaecologists
tive/accurate it is important to assess its use in the clinical management pathway, as highlighted in our review on the use of uterine artery Doppler for the prediction of pre-eclampsia.2 Here, we present evidence of accuracy, but also numbers needed to test and numbers needed to treat (using aspirin as an intervention), to allow the clinician and patient a clearer understanding of how the use of this investigation could affect their management. This we believe is the essence of evidence-based medicine. n References 1 Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group. preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med 2009;6: e1000097. 2 Cnossen JS, Morris RK, ter Riet G, Mol BW, van der Post JA, Coomarasamy A, et al. Use of uterine artery Doppler ultrasonography to predict pre-eclampsia and intrauterine growth restriction: a systematic review and bivariable meta-analysis. CMAJ 2008;178: 701–11.
RK Morris NIHR Clinical Lecturer in Maternal Fetal Medicine, Birmingham Centre for Women and Children’s Health, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham Women’s Hospital, Edgbaston, Birmingham, B15 2TG, UK Accepted 16 July 2014. DOI: 10.1111/1471-0528.13134
Authors’ reply Sir, Like the author of this letter, I too had read with interest the referenced essay in the British Medical Journal regarding the ‘crisis in Evidence Based Medicine’;1 however, I was unable to find any reference to the need to report ‘biological plausibility’ in a systematic review. Current guidelines for the reporting of metaanalysis (Preferred Reporting Items for Systematic Reviews and Meta-Analyses, PRISMA) do not mandate this either.2
591
Copyright of BJOG: An International Journal of Obstetrics & Gynaecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.
