Monday, 20 August 2018

The ancestral optimism and the perfect storm

The optimism of patients

When people get ill, or are afraid of being ill, as a rule we tend to trust doctors and by extension, health systems. But do we really benefit? A systematic review, developed by researchers from the Centre for Research in Evidence-Based Practice of Bond University (Australia), based on 35 surveys (27,323 patients as a whole) concludes that 88% of people overestimate the real benefits of the clinical actions, while 67% underestimated the adverse effects.

See for example, the expectations of people in being able to reduce the risk of dying from secondary prevention programs for breast, prostate and bowel cancers are far above the real data. The dark part of the bars corresponds to the percentage of respondents who overestimate the benefits of the respective preventive tests, and the crosses on the right indicate for which of them this percentage is equal to or greater than 50%.

In the following chart I have chosen the expectations of people in the complications of hip and knee arthroplasty interventions, the need for a second cataract surgery and the chances of not improving pain after having a back operation. The dark part represents the percentage of people who believe that these undesirable or adverse effects are less than that which is actually observed in reality. In all three surveys, the percentages of optimists have been equal to or greater than 50%.

The optimism of doctors

The same authors have published another systematic review of 48 surveys taken from a global 13,011 doctors, from which it can be deduced that only 11% of the professionals know how to fairly value the benefits of the clinical activities they were asked, while a scant 13% are well informed of the corresponding adverse effects. Of the rest, almost 80% opt, like patients, for optimism, both in terms of positive and negative effects.

To illustrate this, I have also chosen from the list of surveys some that I think are interesting. The following chart shows how most doctors overestimate (dark portion of the bars) the reduction of femur fractures and colon cancer due to hormone replacement therapy (HRT) and the ability of antibiotics to reduce pain and fever in people with tonsillitis or acute otitis media (AOM).

And, finally, there are some examples (without a graphic because the selection I made is scattered throughout list) on the opinion of professionals regarding the adverse effects. It’s intriguing that more than half of doctors underestimate the likelihood of recurrent nerve palsy as a consequence of subtotal thyroidectomies, but that they also underestimate the risk of dying as a result of transurethral prostatectomy or the risks inherent in preventive colonoscopies. On the other hand, it’s not without an ideological air that most doctors overestimate the risks of haemorrhage and death of abortions by aspiration.

Modern clinical practice suffers many tensions almost all of them with regard to overdiagnosis and overtreatment. Among the best known are; the consumer climate of today's society, the pressure of industry and the practice of defensive medicine. But now it transpires that the evidence provides us with a new element: the crazy optimism of patients and doctors, which only makes things worse: The perfect Storm.

Jordi Varela

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