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Table of Contents
Year : 2021  |  Volume : 4  |  Issue : 3  |  Page : 42-43

Biases in clinical practice

Department of Neurological Sciences, Christian Medical College Hospital, Vellore, Tamil Nadu, India

Date of Web Publication02-Nov-2021

Correspondence Address:
Dr. Vedantam Rajshekhar
Department of Neurological Sciences, Christian Medical College Hospital, Vellore - 632 004, Tamil Nadu
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJNO.IJNO_406_21

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How to cite this article:
Rajshekhar V. Biases in clinical practice. Int J Neurooncol 2021;4, Suppl S1:42-3

How to cite this URL:
Rajshekhar V. Biases in clinical practice. Int J Neurooncol [serial online] 2021 [cited 2022 Dec 9];4, Suppl S1:42-3. Available from: https://www.Internationaljneurooncology.com/text.asp?2021/4/3/42/329801

All of us are prone to biases of various kinds in our life. However, as clinicians, bias in our practice can have serious consequences for our patients. Bias in clinical practice can be defined as favoring a particular course of management due to personal opinions influencing our judgment. Bias is generally considered to enter decisions on patient management when available evidence is disregarded. I will argue that inappropriate application of evidence is also a form of bias.

I will discuss two forms of bias that clinicians can fall prey to. First, is “conformation bias” and second, is “confirmation bias”.

  Conformation bias Top

This bias is generated by our desire to conform to the opinions and practices of our peers, especially those of the “leaders” in the field. We might have heard or read about their practices in conferences, webinars or scientific journals. Unfortunately, these days social media is also a major source of information about these practices. Most such management practices involve the use of new and often expensive drugs, technology or techniques. While in some instances, there may be variable evidence for these practices, some surgical techniques, which are touted to be effective by prominent surgeons, may not have the benefit of reproducibility in the hands of others. Instances of such techniques and technology abound in neurosurgery – laser discectomy, lumbar and more recently cervical disc replacement surgery, and superficial temporal artery – middle cerebral artery anastomosis for stroke, are a few examples. Over the years, these techniques or technologies have fallen by the wayside as evidence has accumulated about their lack of efficacy. However, the use of these techniques or technologies has probably unnecessarily harmed several patients.

Uncritical adoption of external evidence in the belief that it qualifies as “evidence based medicine (EBM)” is also a form of conformation bias. Practice of EBM occurs at the intersection of personal experience and expertise, patient expectations and affordability, and critical evaluation of external evidence. An unquestioned adoption of management strategies based on external evidence is another form of conformation bias. For example, the routine use of subdural drains after burr hole evacuation of a chronic subdural hematoma is backed by Level 1 evidence.[1] But the question that needs to be explored is whether the patient population being treated by a neurosurgeon is similar to that being included in the randomized controlled trials (RCTs) and the meta-analysis, in terms of age, rates of recurrence and management strategy in the control group?[2] If not, then the surgeon should be circumspect about the routine use of subdural drains as these are associated with some risks. When it comes to expensive “evidence-backed” technology or drug, the patient and his/her family should be informed about the cost-benefit ratio and an informed decision made in consultation with them.

  Confirmation bias Top

This bias, unlike the conformation bias, is mostly internally driven by one's personal beliefs and opinions. The bias leads a person to selectively seek information and “evidence” from the literature, which is line with existing beliefs and opinions. Such behavior reinforces the existing beliefs and opinions. Any information or evidence that is contrary to the personal beliefs is either ignored or unreasonably dismissed. Clinicians learn such biases mostly from their teachers but these can also be imbibed from peers they respect. Of course, one's own experiences also shape one's strongly held beliefs.

An egregious form of confirmation bias can even lead a clinical researcher to, sub-consciously or otherwise, ignore or downplay their own data which does not confirm the clinician's beliefs. Sometimes, the bias is manifested when researchers use post-hoc analysis of data when the a priori hypothesis was not proven by the initial analysis. Such post-hoc analysis is used to put a positive spin on what is essentially a negative study.

  Overcoming biases Top

There are several safeguards to avoid conformation biases. It is important to rationalize the modification of existing management practices. One should honestly question oneself as to whether the adoption of new technique/technology is being done primarily to address the “fear of missing out” (FOMO) and because “everyone” is doing it. If the answer to these questions is “yes”, then withhold the change. The right approach is to ask the following questions: Does the proposed modification address the shortcomings in existing practice? Have the results of this new technique or technology been reproduced by different workers? And, finally, is it cost-effective? If the answer to all these is positive, then change in management is warranted. Even when Level I evidence is available for the treatment of a particular condition, it should be vetted critically as mentioned above.

With respect to confirmation biases, clinicians need not be dissuaded from holding strong beliefs or opinions about patient management options. But they should be encouraged to be on the lookout for evidence which counters their beliefs. If such evidence does become available and is credible, then they should be prepared to shed their strong beliefs and change their management strategy.

  References Top

Alcala-Cerra G, Young AM, Moscote-Salazar LR, Paternina-Caicedo A. Efficacy and safety of subdural drains after burr-hole evacuation of chronic subdural hematomas: systematic review and meta-analysis of randomized control trials. World Neurosurg 2014;82:1148-57.  Back to cited text no. 1
Sivaraju L, Moorthy RK, Jeyaseelan V, Rajshekhar V. Routine placement of subdural drain after burr hole evacuation of chronic and subacute subdural hematoma: a contrarian evidence based approach. Neurosurg Rev 2017;41:165-71.  Back to cited text no. 2


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Conformation bias
Confirmation bias
Overcoming biases

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