Types of studies and research design

Mukul Chandra Kapoor, Mukul Chandra Kapoor

Abstract

Medical research has evolved, from individual expert described opinions and techniques, to scientifically designed methodology-based studies. Evidence-based medicine (EBM) was established to re-evaluate medical facts and remove various myths in clinical practice. Research methodology is now protocol based with predefined steps. Studies were classified based on the method of collection and evaluation of data. Clinical study methodology now needs to comply to strict ethical, moral, truth, and transparency standards, ensuring that no conflict of interest is involved. A medical research pyramid has been designed to grade the quality of evidence and help physicians determine the value of the research. Randomised controlled trials (RCTs) have become gold standards for quality research. EBM now scales systemic reviews and meta-analyses at a level higher than RCTs to overcome deficiencies in the randomised trials due to errors in methodology and analyses.

Keywords: Clinical trials; evidence-based medicine; medical research; meta-analysis.

Figures

Figure 1
Figure 1
Triad of evidence-based medicine
Figure 2
Figure 2
Classification of types of medical research
Figure 3
Figure 3
The evidence-based medicine pyramid

References

    1. Sur RL, Dahm P. History of evidence-based medicine. Indian J Urol. 2011;27:487–9.
    1. Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: What it is and what it isn't. BMJ. 1996;312:71–2.
    1. Greenhalgh T. Effectiveness and efficiency: Random reflections on health services. BMJ. 2004;328:529.
    1. Kapoor MC. Evidence based medicine: Can everything be evident? Ann Card Anaesth. 2011;14:3–5.
    1. Shah HM, Chung KC. Archie Cochrane and his vision for evidence-based medicine. Plast Reconstr Surg. 2009;124:982–8.
    1. Sears ED, Burns PB, Chung KC. The outcomes of outcome studies in plastic surgery: A systematic review of 17 years of plastic surgery research. Plast Reconstr Surg. 2007;120:2059–65.
    1. Levin A. The Cochrane Collaboration. Ann Intern Med. 2001;135:309–12.
    1. Indian Council for Medical Research. Ethical Guidelines for Biomedical Research on Human Participants. 2006. [Last accessed on 2016 May 22]. Available from: .
    1. Röhrig B, du Prel JB, Wachtlin D, Blettner M. Types of study in medical research: Part 3 of a series on evaluation of scientific publications. Dtsch Arztebl Int. 2009;106:262–8.
    1. International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. ICH Harmonised Tripartite Guideline-Guideline for Good Clinical Practice E6 (R1) Step 4 Version Dated 10 June 1996. [Last accessed on 2016 May 22]. Available from: .
    1. International Committee of Medical Journals. Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals Updated December 2015. [Last accessed on 2016 May 25]. Available from: .
    1. Garg AX, Hackam D, Tonelli M. Systematic review and meta-analysis: When one study is just not enough. Clin J Am Soc Nephrol. 2008;3:253–60.
    1. Cook DJ, Mulrow CD, Haynes RB. Systematic reviews: Synthesis of best evidence for clinical decisions. Ann Intern Med. 1997;126:376–80.
    1. Margaliot Z, Chung KC. Systematic reviews: A primer for plastic surgery research. Plast Reconstr Surg. 2007;120:1834–41.
    1. Jørgensen AW, Hilden J, Gøtzsche PC. Cochrane reviews compared with industry supported meta-analyses and other meta-analyses of the same drugs: Systematic review. BMJ. 2006;333:782.
    1. Lyman GH, Kuderer NM. The strengths and limitations of meta-analyses based on aggregate data. BMC Med Res Methodol. 2005;5:14.
    1. Simmonds MC, Higgins JP, Stewart LA, Tierney JF, Clarke MJ, Thompson SG. Meta-analysis of individual patient data from randomized trials: A review of methods used in practice. Clin Trials. 2005;2:209–17.
    1. Schmid CH, Landa M, Jafar TH, Giatras I, Karim T, Reddy M, et al. Constructing a database of individual clinical trials for longitudinal analysis. Control Clin Trials. 2003;24:324–40.
    1. Pogue J, Yusuf S. Overcoming the limitations of current meta-analysis of randomised controlled trials. Lancet. 1998;351:47–52.
    1. Anello C, Fleiss JL. Exploratory or analytic meta-analysis: Should we distinguish between them? J Clin Epidemiol. 1995;48:109–16.
    1. Kamath S, Guyatt G .Importance of evidence-based medicine on research and practice. Indian J Anaesth. 2016;60:622–5.
    1. Dellinger RP, Carlet JM, Masur H, Gerlach H, Calandra T, Cohen J, et al. Surviving sepsis campaign guidelines for management of severe sepsis and septic shock. Crit Care Med. 2004;32:858–73.
    1. Myles PS, Leslie K, Chan MT, Forbes A, Paech MJ, Peyton P, et al. Avoidance of nitrous oxide for patients undergoing major surgery: A randomized controlled trial. Anesthesiology. 2007;107:221–31.
    1. Leslie K, Myles PS, Kasza J, Forbes A, Peyton PJ, Chan MT, et al. Nitrous oxide and serious long-term morbidity and mortality in the evaluation of nitrous oxide in the gas mixture for anaesthesia (ENIGMA)-II trial. Anesthesiology. 2015;123:1267–80.
    1. Myles PS, Leslie K, Chan MT, Forbes A, Peyton PJ, Paech MJ, et al. The safety of addition of nitrous oxide to general anaesthesia in at-risk patients having major non-cardiac surgery (ENIGMA-II): A randomised, single-blind trial. Lancet. 2014;384:1446–54.
    1. van den Berghe G, Wouters P, Weekers F, Verwaest C, Bruyninckx F, Schetz M, et al. Intensive insulin therapy in critically ill patients. N Engl J Med. 2001;345:1359–67.

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