Inappropriate use of randomised trials to evaluate complex phenomena: Case study of vaginal breech delivery

Department of Obstetrics and Gynaecology, University of British Columbia, BC Women's Hospital, Vancouver, BC, V6H 3V5 Canada.
BMJ (online) (Impact Factor: 17.45). 10/2004; 329(7473):1039-42. DOI: 10.1136/bmj.329.7473.1039
Source: PubMed


As randomised trials continue to ascend in the evolution of evidence based medicine, we must recognise and respect their limitations when examining complex phenomena in heterogeneous populations.

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    • "The alluring and authoritative success that RCTs gained over observational research (Hulley et al., 1998), and their significant contribution to improved clinical practice led to the extension of their application to evaluate complex interventions, notwithstanding that their necessary prerequisites (in particular, blinding and intervention standardisation that are essential to ensuring internal validity, the ''crown jewel'' of RCTs) can either be intrinsically or practically unattainable (Kotaska, 2004). "

    International Journal of Nursing Studies 09/2015; DOI:10.1016/j.ijnurstu.2015.09.002 · 2.90 Impact Factor
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    • "Fünf Jahre später kritisierten Glezerman und andere (Giuliani et al., 2002, Kotaska, 2004), die sich die Rohdaten und Analysemethoden genauer angesehen hatten, das wissenschaftliche Vorgehen der Autoren erheblich. Dies führte dazu, dass die Autoren schließlich einräumten, dass die meisten Todesfälle, nämlich 43 von 69, nichts mit der Entbindungsmethode zu tun hatten (Glezerman, 2006). "

    01/2011; 21:133-169.
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    • "*Address correspondence to this author at the Australian Research Centre for Population Oral Health, School of Dentistry, The University of Adelaide , SA 5005, Australia; Tel: +61 8 8303 3292; Fax: +61 8 8303 4858; E-mail: While RCTs are generally considered as the " gold standard " for obtaining solid evidence on the effect of health care interventions, some have questioned their applicability to complex interventions [8] and to health promotion strategies in particular [9-11]. The latter tend to be complex and require a long follow-up that may exceed the attention span of participants, who do not have a problem in the first place. "
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    ABSTRACT: Severe early childhood caries (S-ECC) affects 17% of 2-3 year old children in South Australia impacting on their general health and well-being. S-ECC is largely preventable by providing mothers with anticipatory guidance. Randomised controlled trials (RCTs) are the most decisive way to test this, but that approach suffers from near inevitable loss to follow-up that occurs with preventative strategies and distant outcome assessment. We re-examined the results of an RCT to prevent S-ECC using sensitivity analyses and multiple imputation to test different assumptions about violation of random allocation (1%) and major loss to follow-up (32%). Irrespective of any assumptions about missing outcomes, providing expectant mothers with anticipatory guidance during pregnancy and in the child’s first year of life, significantly reduced the incidence of S-ECC at 20 months of age. However, the relative risk of S-ECC varied from 0.18 (95% confidence interval (CI): 0.06 – 0.52) to 0.70 (95% CI: 0.56 – 0.88). Also the ‘number needed to treat’ (NNT) to prevent one case of S-ECC varied 2.5-fold: from 8 to 20 women given anticipatory guidance. Multiple imputation provided a best estimate of 0.25 (95% CI: 0.11 – 0.56) for the relative risk and of 14 (95% CI: 10 – 33) for the number needed to treat. Avoiding loss to follow-up is crucial in any RCT, but is difficult with preventative health care strategies. Instead of abandoning randomisation in such circumstances, sensitivity analyses and multiple imputation can consolidate the findings of an RCT and add extra value to the conclusions derived from it.
    The Open Dentistry Journal 07/2010; 4:55-60. DOI:10.2174/1874210601004020055
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