Designers will rescue the health sector

Much of what we do in healthcare is communicate ideas. That is far more common than ‘doing’. Executive control over decisions are the purview of the patient. It is a basic tenant of medicine that the patient has autonomy.

Often armed with little more than a stethoscope doctors must communicate to the patient that:

When communication about the evidence base is effective the patient, the practitioner and ultimately the economy benefit. How we communicate such ideas is where innovation has the brightest future. It gives us hope that we can improve outcomes in health without recourse to major policy change or curbing freedom of choice.

We communicate in words, pictures, video, audio and using models. Yet so much of how that is done in the doctor’s office hasn’t changed over the decades. ‘It’s just a virus’ doesn’t cut it any more.

We experience the power of effective communication everyday and in every other area of our lives. Look at your credit card statement this month- does it all make sense? What pressed your ‘purchase‘ button?

What if this extraordinary power deployed so effectively in commerce was unleashed in the clinic?

Picture by Dan Moyle

Be careful when you break eye contact

 

The duration of consults in medicine has been a bone of contention for years. Nowhere has the issue received more attention than in the UK where the issue of access to general practice has been the subject of debate and discussion since at least since the late nineties. The following graph depicts the duration of consults in one data set:

The accompanying commentary summaries the position well:

The shape of the curve highlights the extent of variation, though the mean is just under 12 minutes … In the GP contract 2014 the requirement for a 10 minute consultation has sensibly been dropped.  Some clamour for 15 minutes – and they are right, but for only a small minority of patients.  Many more need under 10 minutes, also right. What is inefficient is allocating the wrong time – too short, and rework results.  Too long, throughput falls and waits rise.

Therefore the issue is not merely the ‘duration’ of consults but what actually transpires in those meetings. Decades of research have identified the tasks for both parties in the consult (the paper below may not have been written by someone whose first language was English but they make their point):

For example: patients face the issues of how to put their concerns on the floor (Robinson and Heritage 2005); how to show themselves to be properly oriented to their bodies (Halkowski 2006, Heritage and Robinson 2006, Heath 2002); how to direct the doctor’s attention toward and away from certain diagnostic possibilities (Gill and Maynard 2006, Gill et al. forthcoming, Stivers 2002b); and how to deal with diagnoses and treatment recommendations that may or may not correspond to their own views and preferences (Heath 1992, Stivers 2002a, 2006, Peräkylä 2002).
From the point of view of doctors, issues include eliciting all of a patient’s concerns (Heritage et al. 2007, Robinson 2001) and designing solicitations that are fitted to the concerns that patients are likely to have (Heath 1981, Robinson 2006); preparing patients for no-problem diagnoses (Heritage and Stivers 1999) as well as difficult diagnostic news (Maynard 2003, Maynard and Frankel 2006); and securing patient agreement in regard to diagnoses (Peräkylä 2006) and treatment recommendations (Stivers 2006, Roberts 1999). Pilnick et al

We know that the doctor will be taking notes or referring to the patients records during the consultation.

Conversation analytic studies have shown that participants of a conversation constantly monitor each other
and the unfolding speech in order to be able to perform the relevant next action when the present speaker has finished his turn of talk (Sacks, Schegloff & Jefferson, 1974). The direction of gaze is of utmost importance here, as gazing at the speaker constitutes a display of attention by the recipient (Goodwin, 1980, 1981; Heath, 1986; Robinson, 1998).

In addition to direction of gaze, the engagement framework may be created and maintained by shifting one’s posture (Kendon, 1990; Schegloff, 1991; Robinson, 1998), or gesturing in the visible field of the intended recipient (Goodwin, 1986; Heath, 1986). Shifts in posture that may be treated as displays of attention or disattention can be analyzed as shifts of ‘home position’ of the body (Schegloff, 1991)

As in everyday conversation, in doctor– patient interaction the participants constantly monitor each other’s movements and direction of gaze (Heath, 1986; Robinson, 1998)

Johanna Ruusuvuor’s research, quoted above also suggests that there are four circumstances in which the consultation becomes dysfunctional insofar as the patient’s narrative is inhibited.

  1. Disengagement with home position away from the patient:

The doctor is seated facing the a desk away from the patient and does not make eye contact with the patient as they start to disclose the reason for the consultation.

2.  Disengagement with manifest shift in orientation:

The home position of the doctor is towards the desk with his head in torque towards the patient. He releases his torque simultaneously as he withdraws his gaze from the patient.

3. Disengagement at critical point of description:

Turning away at a moment when maintaining mutual involvement in a common focus of interest has been made specifically relevant, and when the utterance is still incomplete with only the very core of the complaint pending, seems to be interpreted by the speaker as a disengagement from the role of the recipient.

In the last two examples the postural orientation of the doctors, and the way in which the doctors turned away from the patient to the records within the patients’ turns were enough to convey a disengagement from interaction with the patient

4. Disengagement at critical point of story-telling:

 The doctor’s home position is towards the patient. From time to time he turns his upper body to torque towards the desk, making notes. The doctor disengages when the patient is about to reach the completion of her/his turn.

There are specific moments in which disengaging from interaction with the patients hampers a good outcome because it interrupts the narrative and the conversation becomes disjointed. Therefore it may pay great dividends to note where you are looking and how you are positioned during the consultation.

Picture copyright

For best results engage the entire decision making apparatus

I’ve been sick for two days. I have a runny nose, headache, cough and I’m tired.

We agreed that it was very unpleasant having these symptoms when you are moving boxes around a warehouse all day. I examined him and found signs of an upper respiratory tract infection but nothing worse. Now comes the crucial part. If you are a doctor what do you say in the circumstances? You must have your speech ready because you will almost certainly consult someone like this every day, probably more than once a day. In an essay published in the BMJ Trisha Greenhalgh and colleagues wrote:

Evidence users include clinicians and patients of varying statistical literacy, many of whom have limited time or inclination for the small print. Different approaches such as brief, plain language summaries for the non-expert (as offered by NICE), visualisations, infographics, option grids, and other decision aids should be routinely offered and widely used. Yet currently, only a fraction of the available evidence is presented in usable form, and few clinicians are aware that such usable shared decision aids exist. BMJ 2014

What she appears to be hinting at is that words are not enough and may not efficiently convey what this man needs to make a decision for himself. He has already decided for whatever reason that he needs to see a doctor. He was probably able to ‘self-care’ by taking ‘over the counter’ symptomatic measures. Setting aside the notion that he might have presented to get a medical certificate to claim time off what else may be on his agenda? If we postulate that he might want prescribed medicines believing that they will hasten this recovery then there is the prospect of a disagreement with you as the ‘evidence’ suggests otherwise. He probably has a viral illness. But as David Spiegelhalter and colleagues wrote in Science:

Probabilities can be described fluidly with words, using language that appeals to people’s intuition and emotions. But the attractive ambiguity of language becomes a failing when we wish to convey precise information, because words such as “doubtful,” “probable,” and “likely” are inconsistently interpreted. Science 2011

What the person with the cold needs to know is that we cannot be sure what precise ‘bug’ has caused his symptoms. That the most likely cause is a virus but that his symptoms now do not predict the duration or severity of his illness. However most people get better within 10 days and he is probably suffering the most he will through this illness today. The worst symptoms are those he now describes. the cough may linger for a couple weeks.  Symptomatic treatment might help him feel better and that people who have been prescribed antibiotics do not get better any faster (that last bit is my team’s research which hasn’t yet seen the light of day in a peer-reviewed journal). However he may not factor all of this information into his thinking without pictures. We need to consider how he makes the decision to take your advice. Scientists have studied this and come up with some helpful advice recently. For a start the patient is unlikely to make a decision based on logic alone.

Behavioral economic studies involving limited numbers of choices have provided key insights into neural decision-making mechanisms. By contrast, animals’ foraging choices arise in the context of sequences of encounters with prey or food. On each encounter, the animal chooses whether to engage or, if the environment is sufficiently rich, to search elsewhere. Kolling et al

There are three treatment options; prescribe an antibiotic now, defer prescribing for a couple days or prescribe nothing. The latter is the appropriate course however a goal in this situation is to reach consensus with this person. To present the data to him in a way that engages his entire decision making apparatus. You are able to usher him out the door without anything only to find that he has lost faith in you. How he feels about the matter is critical:

A few years ago, neuroscientist Antonio Damasio made a groundbreaking discovery. He studied people with damage in the part of the brain where emotions are generated. He found that they seemed normal, except that they were not able to feel emotions. But they all had something peculiar in common: they couldn’t make decisions. The big think

The more challenging approach is to communicate respectfully, appropriately and effectively. Pictures can now assist as never before. Yet the habit of using pictures is neither taught nor practised consistently in clinics. Spiegelhalter again:

   The most suitable choice of visualization to illustrate uncertainty depends closely on the objectives of the presenter, the context of the communication, and the audience. Visschers et al. concluded that the “task at hand may determine which graph is most appropriate to present probability information” and it is “not possible to formulate recommendations about graph types and layouts.” Nonetheless, if we aim to encourage understanding rather than to just persuade, certain broad conclusions can be drawn, which hold regardless of the audience.

His team’s recommendations:

  • Use multiple formats, because no single representation suits all members of an audience.
    Illuminate graphics with words and numbers.
  • Design graphics to allow part-to-whole comparisons, and choose an appropriate scale, possibly with magnification for small probabilities.
  • To avoid framing bias, provide percentages or frequencies both with and without the outcome, using frequencies with a clearly defined denominator of constant size.
  • Helpful narrative labels are important. Compare magnitudes through tick marks, and clearly label comparators and differences.
  • Use narratives, images, and metaphors that are sufficiently vivid to gain and retain attention, but which do not arouse undue emotion. It is important to be aware of affective responses.
  • Assume low numeracy of a general public audience and adopt a less-is-more approach by reducing the need for inferences, making clear and explicit comparisons, and providing optional additional detail.
    Interactivity and animations provide opportunities for adapting graphics to user needs and capabilities.
  • Acknowledge the limitations of the information conveyed in its quality and relevance. The visualization may communicate only a restricted part of a whole picture.
  • Avoid chart junk, such as three-dimensional bar charts, and obvious manipulation through misleading use of area to represent magnitude.
  • Most important, assess the needs of the audience, experiment, and test and iterate toward a final design.

The last offers a call to arms for innovators.

Picture by Alan

Is your motto reflected in every interaction?

Every interaction with patients should reflect the motto of the healthcare organization serving their needs.

Motto: A sentence, phrase, or word expressing the spirit or purpose of a person, organization, city, etc., and often inscribed on a badge, banner, etc. Dictionary

I like the motto of the Royal College of General Practitioners, UK:

Cum Scientia Caritas

Compassion with knowledge. So here are a list of unacceptable explanations when someone interacts with a service provider and things deviate from whatever noble aim is adorned above the front door:

  1. I’m not paid to do that
  2. I don’t have the resources
  3. That’s not how things are done
  4. Where’s the evidence?
  5. It’s not my fault
  6. It’s not in the protocol
  7. Too idealistic
  8. It’s not me it’s them
  9. I didn’t know
  10. We didn’t negotiate that in the contract
  11. People expect too much
  12. We never promised that
  13. We might do that in the future
  14. We would never get through the day if we did that for everyone
  15. I don’t care
  16. I only work here
  17. Too busy
  18. Maybe next time
  19. What about me?
  20. It doesn’t matter

Every interaction should reflect what we say and what we believe the patient /customer/ colleague is entitled to from our service or our staff. The response when deviations are reported should also reflect the motto. Choose your motto with care.

Picture by Adrian Clark

 

More can be done to help people who consult doctors

In general practice patients generally present with undifferentiated conditions. People come for help with a cough and not ‘pneumonia’, back pain and not ‘metastatic prostatic cancer’, fatigue and ‘not diabetes’. In a study published in 2015 it was reported that a diagnosis is not established in 36% of patients with health problems. According to the research team half of the symptoms were expected to resolve or persist as ‘medically unexplained’. In their summary the team concludes that:

The study highlights the need for a professional and scientific approach to symptoms as a phenomenon in its own right. Rosendal et al

We also know that the commonest symptoms relate to the musculoskeletal system, respiratory system and the digestive tract. As long ago as 1984 Gordon Waddell and colleagues made a similar point in the BMJ :

The amount of treatment received by 380 patients with backache was found to have been influenced more by their distress and illness behaviour than by the actual physical disease. Patients showing a large amount of inappropriate illness behaviour had received significantly more treatment (p <0 001).

They concluded:

We know that a standard medical history and examination provide a wealth of information not only about the disease from which the patient is suffering but also about how that particular person is reacting to and coping with his or her illness. What is necessary now is to devote as much time and effort to the study and understanding of illness behaviour as we do at present to the investigation of physical disease. Only thus can we put the art of medicine on to a sound scientific basis.

Decades later these words are prophetic and we find that the thrust of research is on the diagnosis and treatment of specific pathology rather than on how to help people to cope with persistent back pain, acute cough or ill defined abdominal pain. This continues to be a bone of contention between doctors and patients as was illustrated in a classic paper by Joe Kai writing about the management of illness in preschool children in general practice:

Parents expressed a need for more information about children’s illness. Advice about the management of common symptoms was insufficient. They sought explanation and detail that was specific and practical to help them make decisions about the likely cause of an illness, how to assess severity, and when to seek professional advice. They wanted to know of any implications of the illness or its treatment and the potential for prevention in the future. Most thought that being more informed would reduce rather than increase their anxiety.

In a literature review published in 2002 in the BJGP Hay and Wilson charted the progress of children under 4 who develop an acute cough:

At one week, 75% of children may have improved but 50% may be still coughing and/or have a nasal discharge. At two weeks up to 24% of children may be no better. Within two weeks of presentation, 12% of children may experience one or more complication, such as rash, painful ears, diarrhoea, vomiting, or progression to bronchitis/pneumonia.

The authors conclude that:

Illness duration may be longer and complications higher than many parents and clinicians expect. This may help to set more realistic expectations of the illness and help parents to decide when and if to reconsult.

By implication, as well as knowing when and how to investigate symptoms, it would help patients if doctors also routinely communicated the natural history of the commonest symptoms including and especially:

  • Acute cough
  • Acute low back pain
  • Rash
  • Depression
  • Sprain /strain

For example it has been demonstrated that the experience of individual doctors on this issue is unreliable. Writing on acute low back pain researchers from New Zealand suggests that 91% of patients stop consulting their doctor at 3 months after the pain starts and long before their symptoms have resolved. Also that only 1:5 patients are free of pain or disability one year after an acute episode of low back pain.

Picture by Tina Franklin

Am I going to be like this forever doctor?

There is an opportunity in nearly every medical interaction to make a substantial difference to the outcome by reassuring. What nearly every patient wants to know is:

How long will this horrible feeling last?

We can be reassuring in the various ways in which we conduct ourselves in healthcare. On the stage, with the props, in the persona we adopt, in the dialogue and in the action. All of it matters. Much of what appears on this blog speaks to these aspects of the consult.

People attend doctors for one main reason. They are worried. It doesn’t matter whether the cause is a minor self-limiting illness or a life-limiting cancer. Symptoms ultimately drive us to the medicine man. Here are the results of a study entitled ‘Why Patients Visit Their Doctors’:

We included a total of 142,377 patients, 75,512 (53%) of whom were female. Skin disorders (42.7%), osteoarthritis and joint disorders (33.6%), back problems (23.9%), disorders of lipid metabolism (22.4%), and upper respiratory tract disease (22.1%, excluding asthma) were the most prevalent disease groups in this population. Ten of the 15 most prevalent disease groups were more common in women in almost all age groups, whereas disorders of lipid metabolism, hypertension, and diabetes were more common in men. Additionally, the prevalence of 7 of the 10 most common groups increased with advancing age. Prevalence also varied across ethnic groups (whites, blacks, and Asians). St. Sauver et al

For each of these conditions it is possible to prepare a response that will reassure the person that things will improve.  It is interesting to read the lay commentary on the data:

What’s funny is that while skin disease is the most common reason for doctor visits in America, it’s usually the least detrimental to overall health……Pretty much everybody (and I mean everybody) has experienced a cold before. You know the symptoms; runny nose; coughing; sore throat; congestion. Due to the high volume of people who get colds every year (most people get multiple colds per year), it’s no surprise that some of those people will see the doctor about it. Therichest

And the implications of this commentary is that the response to patient is a ‘set-play’. Doctors and healthcare organisations can prepare to host a visit from most people who present for help. If you are a doctor what is your interaction like with someone with acne or eczema? How do you respond when this is the reason for attendance is a cold? What do you do? What do you say? Is that reassuring? How do you know? For most if not all these problems much of the treatment includes prescribing ‘tincture of time’ essentially that means reassuring the patient that they will not suffer forever.

There is evidence that such an attitude reduces the impact of the illness:

Clinician empathy, as perceived by patients with the common cold, significantly predicts subsequent duration and severity of illness and is associated with immune system changes. Rakel et al

Picture by Christophe Laurent

Your words are potent medicine


A principle of medical ethics is beneficence:

A moral obligation to act for the benefit of others. Not all acts of beneficence are obligatory, but a principle of beneficence asserts an obligation to help others further their interests. Obligations to confer benefits, to prevent and remove harms, and to weigh and balance the possible goods against the costs and possible harms of an action are central to bioethics. Med Dictionary

In saying that the business of medicine is not so different from many other forms of commerce where someone might offer a solution to what appears to be a problem. What we have learned from studying human interactions is that what is said, how and when it is said has a crucial impact on what the person with the problem decides to do. In medical research the hopes of improving outcomes sometimes seem to focus on labs manned by people in white coats funded by a research grant. What is often overlooked is that it may be possible to change outcomes in healthcare (for better or for worse) by working on the dialogue in the consulting room. What in previous posts I have dubbed the ‘script’ in the ritual that is the consultation.

Beneficence dictates that we act to present the autonomous individual with options in a way that leads them to act in their best interests. That may include having the operation, taking the pills, accepting the referral or the test. But also steering away from  those options if they are not in their best interests. The art of communication received a boost in Robert Cialdini’s book Pre-Suasion. Cialdini catalogues the research on the subtle ways in which we are triggered to make choices from the options on offer. It is hard to summarise this extraordinary book but there are at least four essential lessons:

  1. There are ‘Privileged Moments’.  ‘Influence practitioners’ should target such moments before the interaction to greatly increase their effectiveness. It is possible to speculate what these might be for patients: pregnancy, diagnosis of a significant illness, receipt of worrying test results, significant birthday etc.
  2. During verbal exchanges leading questions try to get you to respond with certain answers and influence your later decisions. For example: “Given the recent cases of death from influenza, how dangerous do you perceive the threat of flu to be?” The way the question is posed is loaded with pre-suasion. By reminding you of these deaths the questioner draws attention to the recency of the topic, and thus the patient will evaluate the danger as high and be primed to accept the offer of vaccination.
  3. Whatever grabs our attention, we think is relevant. As Cialdini says:

All mental activity is composed of patterns of associations; and influence attempts , including pre-suasive ones , will be successful only to the extent that the associations they trigger are favourable to change.

In other words in any situation, people are dramatically more likely to pay attention to and be influenced by stimuli that fit the goal they have for that situation. In medicine being presented with information that suggests that someone might be ‘at risk’ of an illness might lead them to act to reduce the risk. However also in this context the heightened anxiety due to fear messages against for example smoking causes people to be delusional in order to dampen the anxiety effect. We also know that the public has a very poor understanding of numbers. In a study of laypersons published in Health Expectations it was concluded that:

Most participants thought of risk not as a neutral statistical concept, but as signifying danger and emotional threat, and viewed cancer risk in terms of concrete risk factors rather than mathematical probabilities. Participants had difficulty acknowledging uncertainty implicit to the concept of risk, and judging the numerical significance of individualized risk estimates. Han et al

Cialdini offers another insight:

The communicator who can fasten an audience’s focus onto the favourable elements of an argument raises the chance that the argument will go unchallenged by opposing points of view, which get locked out of the attentional environment as a consequence.

It isn’t just the facts but how the facts are presented. There are ways in which to engage if not by pass the logic. The three ‘commanders’ of attention that are highly effective are: the sexual, the threatening and the different. When an issue is presented in the context of these considerations their impact is boosted significantly.

    4. Our word choices matter a lot more than we think, because words get us to do things. The main function of language is not merely to  express or describe, but to influence. Something it does by channeling recipients to sectors of reality preloaded with a set of mental association favorable to the communicators view. Doctors may want to illuminate connections to negative associations and increase connections to positive associations. People also prefer things, people, products, and companies that have an association with themselves. This again emphasizes the vital importance of knowing what matters to the person whom you may wish to influence.

Finally and in medicine very significantly Cialdini draws our attention to the following:

Those that use the pre-suasive approach must decide what to present immediately before their message. But they must also have to make an even earlier decision: whether, on ethical grounds, to employ such an approach.

Every day patients consult doctors. Words are use. These words are designed to influence choices. In medicine the options presented may not take into account factors that the patient may not have disclosed and therefore the choice on offer may not be in their best interests. Nor do those choices take account of the practitioner’s own limitations in evaluating the choices offered. Therefore the first and most important aspect of communicating persuasively is to listen. As Cialdini suggests first determine identifiable points in time when an individual is particularly receptive to a communicator’s message.

Picture by Andreas Bloch

Are you addressing the right problem or the one you think you can fix?


The act of consulting a doctor has been shown to be highly ritualized.

Ritual has long been thought to play an important role in the healing processes used by ancient and non-Western healers. In this paper, I suggest that practitioners of Western medicine also interact with patients in a highly ritualized manner. Medical rituals, like religious rituals, serve to alter the meaning of an experience by naming and circumscribing unknown elements of that experience and by enabling patients’ belief in a treatment and their expectancy of healing from that treatment. John Welch. Journal of religion and health

There are five elements to this ritual:

  1. The stage- office, clinic room, cubicle.
  2. The props- what can be seen and or felt.
  3. The actors- doctor, patient and sometimes nurse or therapist.
  4. The script- what is said.
  5. The action- what is done.

All have an impact on the outcome. The doctor’s ‘script’ is of particular importance as it is what the patient hears. The literature offers evidence of the impact of what is said and how it is said on outcomes for patients:

 The quality of communication both in the history-taking segment of the visit and during discussion of the management plan was found to influence patient health outcomes. The outcomes affected were, in descending order of frequency, emotional health, symptom resolution, function, physiologic measures (i.e., blood pressure and blood sugar level) and pain control. M.A Stewart CMAJ

One conclusion of the literature review published in CMAJ was that the process of sharing information includes a discussion about what the patient understands to be the problem and their options with regard to treatment:

These four studies taken together debunk the myth that the only alternative to the physician’s total control of power in the therapeutic relationship is his or her total abdication of power. They indicate that patients do not benefit from the physician’s abdication of power but, rather, from engagement in a process that leads to an agreed management plan.

This issue assumes great significance when it comes to difficult consultations in which it is perceived that the patient is seeking an option that is not in their best interests. Greenhalgh and Gill wrote the following commentary in the BMJ in 1997:

Two thirds of consultations with general practitioners end with the issuing of a prescription. The decision to prescribe is influenced by many factors, to do with the doctor, the patient, the doctor-patient interaction, and the wider social context, including the effects of advertising and the financial incentives and disincentives for all parties. Hardline advocates of rational drug use do not look kindly on variations in prescribing patterns that cannot be explained by purely clinical factors. The prescriber who allows the “Friday night penicillin” phenomenon to sway his or her clinical judgment tends to do so surreptitiously and with a guilty conscience.

The team go on to conclude that:

The act of issuing a prescription is the culmination of a complex chain of decisions. It is open to biomedical, historical, psychosocial and commercial influences, no aspect of which can be singled out as the ”cause” of non-rational prescribing. The search should continue for methods to measure the interplay of these disparate factors on the decision to prescribe.

Michael Bungay Stanier offers an approach to business coaching by focusing on what a person perceives to be their challenge, what they want and how that choice might be impacting on their other options. A similar approach can be taken in medicine. Two decades after Trish Greenhalgh’s editorial in the BMJ there are still many circumstances in which doctors find it challenging to negotiate options these include but are not limited to:

In this context our team surveyed nearly 9000 patients who had been prescribed antibiotics for Upper Respiratory Tract Infections during the latest flu season. We surveyed patients using a validated tool on the third day and the seventh day after a prescription was issued. We look forward to presenting the results at the forthcoming GP17 conference. We will be offering information on the following questions:

  1. What is the profile of patients who were offered a prescription?
  2. What was the symptom profile at these time points and how does this compare with data on patients who have been offered no treatment in other studies?
  3. What are the characteristics of the respondents to the survey?
  4. What proportion of respondents completed the course of treatment?
  5. What proportion of respondents also took regular symptomatic measures?
  6. What is the profile of patients with relatively severe symptoms at each time point?
  7. Are longer consultations or type of antibiotic predictive of compliance with treatment?
  8. Within the limitations of a study that offers only the patient perspective what might help people with Upper Respiratory Tract Infections?

Picture by US Army Garrison Red

For a medical test to be of value the patient needs to see a doctor

Among the commonest tests ordered by doctors is a full blood count. The test presents signs of iron deficiency anaemia. The prevalence of that condition is reported as follows:

In Australia in 2011–12, around 760,000 people aged 18 years and over (4.5%) were at risk of anaemia, with women more likely to be at risk than men (6.4% compared with 2.5%). The risk of anaemia was highest among older Australians, with rates rapidly increasing after the age of 65 years. People aged 75 years and older were more likely to be at risk of anaemia than all other Australians, with 16.0% in the at risk range compared with 3.6% of Australians aged less than 75 years. Australian Health Survey

With regard to this blood test (AACC):

  • Haemoglobin (Hb)—may be normal early in the disease but will decrease as anaemia worsens
  • Red blood cell indices—early on, the RBCs may be a normal size and colour (normocytic, normochromic) but as the anaemia progresses, the RBCs become smaller (microcytic) and paler (hypochromic) than normal.
    • Average size of RBCs (mean corpuscular volume, MCV)—decreased
    • Average amount of haemoglobin in RBCs (mean corpuscular haemoglobin, MCH)—decreased
    • Haemoglobin concentration (mean corpuscular haemoglobin concentration, MCHC)—decreased
    • Increased variation in the size of RBCs (red cell distribution width, RDW)
    • A guide to interpreting the test is here

Therefore among the pathognomonic features of established iron deficiency anaemia (IDA) is a low Mean Corpuscular Volume (MCV). The sensitivity and specificity of a low MCV for a diagnosis of iron deficiency anaemia are quoted as  42% and 93%. Assuming a prevalence of 3.6% in the under 75 year old age group this means that if 100 adults in Australia had a full blood count then 3-4 will have iron deficiency anaemia. Screening these people for IDA with this test 8.3% of people will be told they have an abnormal test i.e. 8 people. Of these only 1-2 will be a true positive for IDA. On the other hand 6-7 may be misled into thinking they might have iron deficiency. 91 will be told they have a normal test in this case 2 may be incorrectly reassured. Of course there are other significant conditions which present with a microcytosis ( low MCV) although ‘treatment’ is not necessary in many such cases and also screening for IDA involves other and more sensitive tests.

If the prevalence of the condition was 20%, then even the modest sensitivity and specificity of this test would identify more people at risk of IDA even though it will also miss people with the condition.

  • Number of people with positive test: 14, correctly identified: 8
  • Number of people with negative result: 86, incorrectly reassured: 11

In practice the sensitivity and specificity of tests may be assumed closer to 90% in each case. Given these figures the numbers of people from 100 people test and correctly identified, incorrectly reassured or told they are ill depends on the prevalence. The prevalence of most pathology in the community is low often well below 1%. The figures are presented in the infographic below.

Prevalence 0.005% ( 5 per 1000 people, e.g. hypothyroidism )  2% ( e.g. diabetes)  20% (e.g. common and plantar warts).

From these figures it can be seen that testing is more fruitful in circumstances in which the prevalence is high. The prevalence is higher in those who have signs and symptoms of a condition. One could argue therefore that the ‘prevalence’ is much higher in those who choose to consult a doctor as opposed to the ‘prevalence’ in the community.  For iron deficiency anaemia these circumstances are well known. Which means an effective consultation in which the patient is heard and examined is crucial to interpreting test results. As can be seen from the calculations there is a substantial risk of labelling people as ill, or requiring yet more tests given the modest prevalence of most conditions in the community and where there might be an indiscriminate use of tests.

It is hard to disagree with Campbell and colleagues who considered this issue and noted that:

1) Diagnosis is based on a combination of tests and clinical examination and there is little research based on the sensitivity and specificity of the combination of different examinations as opposed to a one-off test, which is why GPs are unlikely to know the values.

2) It is unclear what is meant by the prevalence of asthma or diabetes for these GPs. It is not the proportion of people in the population with the disease, but rather the proportion of people who come to consult who have the disease (perhaps with similar age and clinical history). This proportion is likely to be quite high and so the issue of overestimating the positive predictive value is less important.

3) The prevalence of the disease will also depend on the severity of the disease being tested for and so this also muddles the calculations.

We might however equally reasonably expect doctors to have an understanding of the issue if only because the practice of medicine involves the most crucial of ‘tests’ the history and the examination and this issue highlights the importance of that activity. Tests that are not appropriately interpreted can be harmful if only because they become a source of anxiety.

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What are the limitations of the physical examination in practice?

 

The ideal innovation is inexpensive, readily incorporated into practice and has substantial patient benefits. In this context the humble physical examination is a strong candidate. However it is reported that in practice laboratory and or radiological tests are requested more often than not. Here is a quote from an editorial in the British Medical Journal (2009):

In the first camp are those who pine for the old days, bemoan the loss of clinical bedside diagnostic skills, and complain that no one knows Traube’s space or Kronig’s isthmus. In the second camp are those who say good riddance and point out that evidence based studies show that many physical signs are useless; some might even argue that examining the patient is just a waste of time. Verghese and Horwitz

Research suggests that most diagnoses are based on the history and examination:

In this prospective study of 80 medical outpatients ….in 61 patients (76%), the history led to the final diagnosis. The physical examination led to the diagnosis in 10 patients (12%), and the laboratory investigation led to the diagnosis in 9 patients (11%). The internists’ confidence in the correct diagnosis increased from 7.1 on a scale of 1 to 10 after the history to 8.2 after the physical examination and 9.3 after the laboratory investigation. These data support the concept that most diagnoses are made from the medical history. The results of physical examination and the laboratory investigation led to fewer diagnoses, but they were instrumental in excluding certain diagnostic possibilities and in increasing the physicians’ confidence in their diagnoses. Peterson et al

In only one of six patients in whom the physician was unable to make any diagnosis after taking the history and examining the patient did laboratory investigations lead to a positive diagnosis. BMJ 1975

Also the value of tests is contested in some cases:

Information from the history, physical examination, and routine procedures should be used in assessing the yield of a new test. As an example, the method is applied to the use of the treadmill exercise test in evaluating the prognosis of patients with suspected coronary artery disease. The treadmill test is shown to provide surprisingly little prognostic information beyond that obtained from basic clinical measurements. The JAMA network

A considerable number of plain abdominal films taken for patients with acute abdominal pain could be avoided by focusing on clinical variables relevant to the diagnosis of bowel obstruction. European Journal of Surgery

However the predictive value of the physical examination appears to depend on the clinical scenario. If the patient appears ill it is far more likely that they will have clinical signs:

In order to study the occurrence and positive predictive value of history and physical examination findings suggestive of serious illness in ill-appearing and well-appearing febrile children, 103 consecutive children aged ≤24 months with fever ≥38.3°C were evaluated from July 1, 1982 to Nov 24, 1982….The positive predictive values of abnormal physical examination findings for serious illness in ill-appearing (11 of 14, 79%) and well-appearing children (3 of 12, 25%) were significantly different (P = .02 by Fisher’s exact test). The trends for abnormal history findings in ill-appearing and well-appearing children were similar to those for abnormal physical examination findings but did not achieve statistical significance. The results, indicating an important interaction between a febrile child’s appearance and physical examination findings, are discussed in terms of probability reasoning in clinical decision making. McCarthy et al

In some common clinical scenarios it is difficult to find objective evidence in support of a diagnosis and tests are necessary. There are many examples including:

Irritable bowel syndrome

Individual symptoms have limited accuracy for diagnosing IBS in patients referred with lower gastrointestinal tract symptoms. The accuracy of the Manning criteria and Kruis scoring system were only modest. Despite strong advocacy for use of the Rome criteria, only the Rome I classification has been validated. Future research should concentrate on validating existing diagnostic criteria or developing more accurate ways of predicting a diagnosis of IBS without the need for investigation of the lower gastrointestinal tract. Ford et al

Heart Failure

Differences in clinical parameters in heart failure patients with decreased versus normal systolic function cannot predict systolic function in these patients, supporting recommendations that heart failure patients should undergo specialized testing to measure ventricular function. Thomas et al

Painful shoulder

Thirty one consecutive patients with a first flare of shoulder pain were prospectively included in the study. All had a physical examination performed by two blinded rheumatologists. Ultrasonographic examination was carried out within one week of the physical examination by a third rheumatologist experienced in this technique who had no knowledge of the clinical findings. Ultrasonography was considered the optimal diagnostic technique. Naredo et al

Also relevant are the physician’s skill in eliciting and interpreting signs:

Agreement between 24 physicians on the presence or absence of respiratory signs was investigated. The physicians were divided into six sets of 4; each set examined 4 patients with well-defined chest signs. There was generally poor agreement about particular signs. Overall, the 4 physicians in a set were in complete agreement only 55% of the time. Some signs such as wheezing seemed to be more reliably elicited than others such as whispering pectoriloquy. Comparison of diagnoses based on the clinical findings with the correct diagnoses supported by investigations showed that 28% of physicians’ diagnoses were incorrect. The more often the examiners differed from the majority on the presence or absence of a sign, the more likely they were to make an incorrect diagnosis.  The Lancet

In some cases physical signs are unreliable:

A review of published studies of patients suspected of having pneumonia reveals that there are no individual clinical findings, or combinations of findings, that can rule in the diagnosis of pneumonia for a patient suspected of having this illness. However, some studies have shown that the absence of any vital sign abnormalities or any abnormalities on chest auscultation substantially reduces the likelihood of pneumonia to a point where further diagnostic evaluation may be unnecessary. JAMA

Therefore always relying on physical signs without conducting tests is unsafe. However the value of the clinical examination as an integral part of the patient experience was eloquently articulated in the BMJ editorial:

A third view of the bedside examination, and one that we advocate, is that it is not just a means of data gathering and hypothesis generation and testing, but is a vital ritual, perhaps the ritual that defines the internist. Rituals are all about transformation. The elaborate rituals of weddings, funerals, or inaugurations of presidents are associated with visible transformation. When viewed in that fashion, the ritual of the bedside examination involves two people meeting in a special place (the hospital or clinic), wearing ritualised garments (patient gowns and white coats for the doctors) and with ritualised instruments, and most importantly, the patient undresses and allows the doctor to touch them. Disrobing and touching in any other context would be assault, but not as part of this ritual, which dates back to antiquity. Verghese and Horwitz

Common sense dictates that where the patient appears unwell the physical examination will have a higher yield. In those circumstances clinical examination is crucial:

Misdiagnosis of acute appendicitis is more likely to occur with patients who present atypically, are not thoroughly examined (as indexed by documentation of a rectal examination), are given IM narcotic pain medication and then discharged from the ED, are diagnosed as having gastroenteritis (despite the absence of the typical diagnostic criteria), and with patients who do not receive appropriate discharge or follow-up instructions. Rusnak et al

Therefore the physical examination has an incalculable value not necessarily obviating the need for tests but increasing patient satisfaction and reducing the risk of litigation. Click the link for an excellent video on examination.

 

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