Evidence Based Medicine Series. Part 4. Why some good studies with clinically important results cannot be applied to our patients
One major misconception towards EBM practitioners is thatthey push to adopt all valid and clinically important evidencewithout having a second thought. Such assumptions stemfrom an incomplete understanding of the definition ofEBM.1,2 A crucial step in EBM is the assessment on whetherthe evidence fits our population and individual patients,hence whether adopting such evidence is possible orappropriate. Ignoring this step would in fact undo our hardwork in the preceding steps of EBM.
We have previously covered the assessment of internalvalidity and clinical importance. These aspects of criticalappraisal, although important, may be seen as tedious andtime-consuming by the busy clinicians.3,4 The good newsis that they may already have been done by others on ourbehalf. Many clinical studies are critically appraised soonafter they appear by people who are skilled in this area.Referring to those pre-appraised resources is one way tosave our work and reduce uncertainties on the value of aclinical study. However, certain steps in the practice of EBMrequire our own efforts at all times. These include askinganswerable, relevant clinical questions, as coveredpreviously, and deciding the applicability of the evidence,as we aim to cover here. (copied from article)
Sackett DL, Rosenberg WM, Gray JA, et al. Evidence based medicine: what it is and what it isn’t. BMJ. 1996;312(7023):71-2.
Straus S, Haynes B, Glasziou P, et al. Misunderstandings, misperceptions, and mistakes. Evid Based Med. 2007;12(1):2-3.
Lam WW, Fielding R, Johnson JM, et al. Identifying barriers to the adoption of evidence-based medicine in clinical clerks: a longitudinal focus group study. Med Educ. 2004;38(9):987-97.
Green M, Ruff T. Why do residents fail to answer their clinical questions? A qualitative study of barriers to practicing evidence-based medicine. Acad Med. 2005;80(2):176-82.
Dans A, Dans L, Group FtEBW, et al. How to decide on the applicability of clinical trials results to your patient. Centre for Health Evidence; 1998 [updated 1998-2007; cited 3 September 2009]. Available from: http://www.cche.net/usersguides/trials.asp.
Straus SE, Sackett DL. Applying evidence to the individual patient. Ann Oncol. 1999;10(1):29-32.
Rothwell PM. Factors that can affect the external validity of randomised controlled trials. PLoS Clin Trials. 2006;1(1):e9.
Bailey RC, Moses S, Parker CB, et al. Male circumcision for HIV prevention in young men in Kisumu, Kenya: a randomised controlled trial. Lancet. 2007;369(9562):643-56.
Kenya 2007 Estimates report with revised HIV prevalence and incidence trends. Nairobi: National AIDS Control Council; 2008 [updated 2008; cited 7 September 2009]. Available from: http://www.nacc.or.ke/2007/default2.php?active_page_id=307&aid=6&newsid=315.
UNAIDS: Country Responses: Countries. Geneva: UNAIDS Secretariat; 2008 [updated 2008; cited 7 September 2009]. Available from: http://www.unaids.org/en/CountryResponses/Countries/malaysia.asp.
Mugford M, Elbourne D, Field D. Extracorporeal membrane oxygenation for severe respiratory failure in newborn infants. Cochrane Database Syst Rev. 2008(3):CD001340.
Briel M, Schuetz P, Mueller B, et al. Procalcitonin-guided antibiotic use vs a standard approach for acute respiratory tract infections in primary care. Arch Intern Med. 2008;168(18):2000-7; discussion 7-8.
Ramanathan R, Rasmussen MR, Gerstmann DR, et al. A randomized, multicenter masked comparison trial of poractant alfa (Curosurf) versus beractant (Survanta) in the treatment of respiratory distress syndrome in preterm infants. Am J Perinatol. 2004;21(3):109-19.
Malloy CA, Nicoski P, Muraskas JK. A randomized trial comparing beractant and poractant treatment in neonatal respiratory distress syndrome. Acta Paediatr. 2005;94(6):779-84.
Sweet DG, Halliday HL. The use of surfactants in 2009. Arch Dis Child Educ Pract Ed. 2009;94(3):78-83.
Seger N, Soll R. Animal derived surfactant extract for treatment of respiratory distress syndrome. Cochrane Database Syst Rev. 2009(2):CD007836.
Soll RF, Blanco F. Natural surfactant extract versus synthetic surfactant for neonatal respiratory distress syndrome. Cochrane Database Syst Rev. 2001(2):CD000144.
Chabner BA, Roberts TG Jr. Timeline: Chemotherapy and the war on cancer. Nat Rev Cancer. 2005;5(1):65-72.
DeVita VT Jr, Chu E. A history of cancer chemotherapy. Cancer Res. 2008;68(21):8643-53.
Lichtman MA. Battling the hematological malignancies: the 200 years’ war. Oncologist. 2008;13(2):126-38.