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Letters Opinion and evidence in guidelines

What is opinion and what is evidence?

BMJ 2019; 366 doi: (Published 13 September 2019) Cite this as: BMJ 2019;366:l5395

Rapid Response:


Evidence-based Medicine (EBM) was first suggested in 1992 to revolutionize the ‘Approach’ to ‘Patient Care’ hinged solely on ‘Best Available Research Evidence’ to the complete de-emphasis on such ‘Considerations’ as: Clinical Intuition, Unsystematic Clinical Experience and Pathophysiological Rationale regarding the Disease [1]. This ‘Communication’ is stimulated by the Presentation: ‘What is Opinion and what is Evidence?’ [2]. ‘Evidence’ was stated as ‘Facts in support of a Conclusion’ while ‘Opinion’ was ‘View/ Judgement formed about something but not necessarily based on Facts’ [3]. It was indicated that, in ‘Guidelines Development’, clear distinction should be made concerning Facts, Evidence and Opinion. Facts and Opinion should be regarded as Evidence and an ‘Evidence Hierarchy’ adopted for use [2]. A pervading ‘Practice Challenge’ is the value of Facts, Evidence and Opinion in ‘Patient Care’!

Since its first introduction, EBM has metamorphosed phenomenally that it can be aptly captured as ‘Work In Progress’ [4]. The original ‘EBM Movement’ disposed a Framework for the ‘Practice of Medicine’ based only on ‘Best Available Research Evidence’ [1]. There were ‘Issues’ with ‘Patient Care Outcomes’! This, in 1992, led to some other ‘Patient-Care Decision-making Models’ which sought to incorporate ‘Clinical Expertise’ into ‘Evidence-based Decision-making in Patient Care’. This was the genesis of the ‘Pyramid of Evidence’ [5]. ‘Clinical Expertise’, possibly also ‘Expert Opinion’, was considered as ‘Evidence’ but of very ‘Low Quality’ and ‘Internal to Evidence’ [6]. The ‘Evidence Pyramid’ reflects the ‘Quality/ Hierarchy of Evidence’re: Rigorous Process involved, avoidance of Bias and establishment of ‘Cause-Effect’/ ‘Causality’. In this ‘Pyramid’, the ‘Randomized Controlled Trials (RCTs)’ are at the ‘Top’ and represent a ‘Small Proportion of Studies’ with ‘Clinical Expertise’/ ‘Expert Opinion’ at the ‘Bottom’ and most abundantly available [6]. In the ‘EBM Work In Progress’, the ‘GRADE Model’ evolved with the consideration of the ‘Quality of Conduct of Studies’ and ‘Benefits-Harm Balance’ but it is an extrapolation of the ‘Evidence Pyramid’ without being a ‘Pyramid’; GRADE is ‘Grading Recommendations Assessment Development and Evaluation’. In the ‘GRADE Model’, the ‘Expert Opinion’ is considered both as ‘Internal and External to Evidence’ [6] ! The ‘Expert Opinion’ is required to ‘Interpret Evidence’ in both the ‘Evidence Pyramid’ and the ‘GRADE Model’! There were still unanswered ‘Issues’ particularly with ‘Expert Opinion’!

With further ‘EBM Movement Metamorphosis’, there evolved the ‘New Model’ involving ‘More Effective and Efficient Diagnosis’ and more ‘Compassionate in addressing Patient’s Predicament’ in making Clinical Decisions in Patient Care [7] ! For the first time, and in 1996, a ‘Parameter’ that is ‘External to Evidence’ was given a strong consideration in ‘Evidence-based Decision-making in Patient Care’! This is ‘Patient Perspectives’!! From 1997, the ‘EBM Movement’ was revolutionized with the ‘Three Circles of Influence Model’ including ‘Research Evidence’, ‘Clinical Expertise’ and ‘Patient Values and Preferences’ [8] ! It was strongly recommended that for EBM, there should be consideration of the ‘Three Circles of Influence’. The Patient should be strongly considered in ‘Patient Care Decisions’! Some will consider ‘Patient Perspectives’ as some ‘Form of Evidence’ recalling that ‘Evidence’ is ‘Facts in support of a Conclusion’ [3] ! So we have ‘Evidence’ in ‘Hierarchy of Evidence’: ‘Research Evidence’, ‘Expert Opinion’/ ‘Clinical Expertise’ and ‘Patient Perspectives’! What is Opinion and what is Evidence [2]? ‘Expert Opinion’ matters!

Still evolving, the ‘EBM Movement’ was disposed as another construct of ‘Three Circles of Influence Model’ but these were: ‘Research Evidence’, ‘Patient’s Preferences and Actions’ and ‘Clinical State and Circumstances’ [9] ! There was an attempt to distinguish ‘Patient Values and Preferences’ from ‘Patient’s Preferences and Actions’. This is not a matter for this moment but ‘Patient Action’ could address ‘Patient Compliance’ as a Case-in-Point! Still clearly different is the ‘Circle of Clinical State and Circumstances’ which may reflect a ‘Complex Consideration’ of ‘Patient Disease/ Disorder’, ‘Index Clinical Presentation’, ‘Existent Co-Morbidities’ and ‘Known Medical History’!! This ‘Model’ could be considered as ‘Four Circles of Influence Model’ with the additional infusion of the ‘Circle of Influence of ‘Clinical Expertise’’. The ‘Clinical Expertise’ in the new ‘Model’ is considered as the ‘Integral Synthesis’ of the other ‘Three Circles of Influence’: ‘Research Evidence’, ‘Patient’s Preferences and Actions’ and ‘Clinical State and Circumstances’!!!

Now for the ‘Thrust’ of this ‘Presentation’, it is my modest disposition to ‘Contextualize’ the ‘Circles of Influence’ as ‘Parameters’ and, therefore, the ‘Four Circles of Influence’ may be appreciated as a ‘Four-Parameter Model’ for EBM. For a meaningful and impactful EBM, the ‘EBM Movement’ needs to consider several ‘Other Parameters’ beyond the current ‘Four Parameters’! Herewith the ‘New EBM Model’: ‘Multiparameter-based Medicine (MBM)’!! Some of the ‘Additional Parameters’ are: ‘Cultural/ Traditional Parameter’, ‘Family Parameter’, ‘Societal Parameter’, ‘Health-related Governance Parameter’, ‘Resources Availability Parameter’ and still adding [3] !! These ‘Additional Parameters’ are to be considered if the desired ‘Impactful Patient Care’ is to integrate ‘Biomedical Medicine-related Patient Care’ with ‘Social Medicine-related Patient Care’ to achieve a ‘Holistic Patient Care’ which is the ‘Thrust’ of this disposed ‘Multiparameter-based Medicine (MBM)’!!

Herewith a more difficult ‘Issue’: the ‘EBM Movement’ started with hinging ‘Clinical Decision-making and Patient Care’ solely on ‘Research Evidence’ while vacating the ‘Other Considerations’! All subsequent ‘Evolving Models’ in the ‘EBM Movement’ have included and involved the ‘Research Evidence Parameter’ as a ‘Sine Qua Non’ for meaningful and impactful ‘Patient Care’! This Presentation will now focus some further attention on ‘Research Evidence’!! Concerning ‘Research Evidence’, the ‘Best Available Research Evidence’ in the ‘Evidence Pyramid’ is ‘Systematic Reviews and Meta-Analyses’ [10]. These are ’Rigorous Evaluation and Statistical Analyses of the Outcomes of Several Systematically sourced Studies which address the same ‘Research Question’ with assured Trustworthiness, Transparency and Quality of the ‘Summarized Report’’ [10]! Several ‘Critical Dissections’ of ‘Systematic Reviews and Meta-Analyses’ unveil a plethora of ‘Difficulties’ making the ‘Invested Premium’ on these ‘Top-of-the-Bracket Research Evidence’ an evolving ‘Conceptual Conversation’ with an unacceptably ‘Decreasing Half-Life’ by the day!! This ‘Matter’, ostensibly for another day, will be ventilated further hopefully in the near future but suffice it to dispose some ‘Tantalizers’ here!!

Some ‘Tantalizing Difficulties’ undergirding the ‘Increasing Conceptual Erosion’ of ‘Systematic Reviews and Meta-Analyses’ as the ‘Terminus in Excellence’ for ‘Research Evidence’ concern ‘Sensitivity Analysis’, ‘Heterogeneity Analysis’ and ‘Publication Bias Analysis’ [10] ! A ‘Treatise’ on these ‘Issues’ is a ‘Discourse’ for another day!

1. Evidence-based Medicine Working Group. Evidence-based Medicine: A new approach to teaching practice of medicine. JAMA 1992; 268 (17):2420-2425
2. Forsyth S. What is opinion and what is evidence? BMJ 2019; 366:l5395 of 13th September 2019
3. Schunemann HJ, Zhang Y, Oxman AD. Distinguishing opinion from evidence in Guidelines. BMJ 2019; 366:l4606 of 19th July 2019
4. Djulbegovic B, Guyatt GH. Progress in evidence-based medicine: a quarter century on. Lancet 2017; 390 (10092). Doi: 10.1016/S0140-6736(16)31592-6
5. Sackett DL, Straus SE, Richardson WS et al. Evidence-based Medicine: how to practice and teach Evidence-based Medicine. 2. Edinburgh: Churchill. Livingstone 1992
6. GRADE Working Group. Grading quality of evidence and strength of recommendations. BMJ 2004; 328 (7454):1490
7. Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence-based Medicine: What it is and what it isn’t. BMJ 1996; 312:71-72
8. Sackett DL. Evidence-based Medicine. Seminars Perinatol 1997; 21 (1):3-5
9. Haynes BR, Devereaux PJ, Guyatt GH. Clinical expertise in the era of evidence-based medicine and patient choice. BMJ 2002; 7:36-38
10. Haidich AB. Meta-analysis in medical research. Hippokratia 2010; 14 (Suppl 1):29-37

Professor Charles Osayande Eregie,
MBBS, FWACP, FMCPaed, FRCPCH (UK), Cert. ORT (Oxford), MSc (Religious Education),
Professor of Child Health and Neonatology, University of Benin, Benin City, Nigeria,
Consultant Paediatrician and Neonatologist, University of Benin Teaching Hospital, Benin City, Nigeria,
UNICEF-Trained BFHI Master Trainer,
ICDC-Trained in Code Implementation,
*Technical Expert/ Consultant on the FMOH-UNICEF-NAFDAC Code Implementation Project in Nigeria,
*No Competing Interests.

Competing interests: No competing interests

04 October 2019
Professor of Child Health and Neonatology, University of Benin and Consultant Paediatrician and Neonatologist, University of Benin Teaching Hospital, Benin City, Nigeria. Also, UNICEF-Trained BFHI Master Trainer and ICDC-Trained in Code Implementaion. Also a Technical Expert/ Consultant on FMOH-UNICEF-NAFDAC Project on Code Implementation in Nigeria
Institute of Child Health, University of Benin, PMB 1154, Benin City, Nigeria