We assume that the medicine we receive is evidence based and up to date, but in fact it can take an average of 17 years for evidence to filter down to practice and, in some cases, up to 50 years.
For example, even though Dr Spock first suggested in 1956 that babies be placed on their tummies to sleep, it took until the early 2000s for the evidence to show conclusively that putting them face up was safer. By then a thorough analysis of a number of studies formed into a "forest review" all pointed to the one conclusion.
Between 2002 and 2011, €27 million was spent on prescriptions for glucosamine in this country.
Despite the fact that the National Institute for Health and Care Excellence (NICE) in the UK recommended in 2008 that it should not be prescribed for osteoarthritis, prescriptions continued to be issued for a few more years, indicating a "lag between evidence availability and uptake by clinicians", according to a research article published late last year by the Health Research Board's Centre for Primary Care Research at the Royal College of Surgeons in Ireland. It has now been removed from prescription in both Britain and Ireland.
Eoin O’Brien, professor of molecular pharmacology at UCD, writes in these pages about the additional problem of procedures being offered to patients in the absence of adequate evidence.
“We should always try to base recommendations for treatment and management on firm evidence, and the best evidence comes from controlled trials. Once we have that evidence, we need to find better ways of communicating it to GPs and to the public.”
Systematic review Not all evidence is equal: a pronouncement by one medical expert has been described as the "least valid form of evidence", while a systematic review is considered the best.
Being a review of all the available evidence (sometimes the negative is suppressed), a systematic review is more likely to be valid and credible. For example, Dr Andrew Wakefield's notorious and disproven linking of the MMR vaccine to autism was actually based on a very small study. Wakefield has been removed from the medical register of the British General Medical Council.
Since May 2011, there is a legal duty for all doctors registered in Ireland to show that they are maintaining their professional competence and this is overseen by the Medical Council. Doctors need to complete 50 hours of professional development activity a year, in addition to one clinical audit which focuses on practice improvement. Several postgraduate medical training bodies operate professional competence schemes.
Medical students are now being taught how to search and critically appraise the best “evidence-based medicine” (EBM), a term coined in the 1990s, even during consultations with patients.
But, of course, evidence can’t be applied without factoring in a patient’s particular history, the doctor’s expertise and the patient’s own wishes.
Secondary evidence There are now a variety of "secondary evidence" sources that make it easier for doctors and their patients to see what the evidence is showing, with studies being assessed and weighted by certain criteria.
For example, doctors can use a well-laid-out site such as thennt.com to demonstrate to their patients why a prescription for antibiotics isn’t necessarily going to help acute bronchitis in adults, as shown in iti.ms/1i4wvn9.
“The core value of the NNT is its straightforward communication of the science that can help us understand the likelihood that a patient will be helped, harmed, or unaffected by a treatment.”
However, with the increasing demands and heavy workloads experienced by many doctors, it is not surprising that a Dutch study published last year on barriers to the use of EBM found that GP trainees complained they just didn’t have the time: “When busy, searching for evidence is not a priority to me;” “The time I have per patient is insufficient to also search for answers to my questions;” and “During consultations, I have insufficient time to work according to EBM,” they said.
"It's very dependent on the individual GP, to be honest," says Dr Cliona Lewis, a GP and part-time clinical lecturer in general practice at RCSI. "Our days are extraordinarily busy just trying to manage the ordinary day-to-day issues that arise during patient consultations."
Major investment A recent major investment is the Dublin Centre for Clinical Research (DCCR), which was made possible through the Wellcome Trust and the HRB.
The aim of the DCCR is to provide the physical space, facilities and trained staff needed to support collaborative clinical research studies across Dublin involving the TCD, UCD and RCSI medical schools and their associated teaching hospitals.
Educational programmes associated with the DCCR and its work will ensure that evidence critical to improving clinical practice standards can be disseminated widely to hospital colleagues and community practitioners, says Dr Martina Hennessy, director of undergraduate teaching and learning at the TCD school of medicine.
Using search engines wisely
Searching for information on the internet has been likened to drinking from a fire hydrant. Doctors advise against using search engines such as Google because of the lack of filtering and assessment of what is put there.
Pre-appraised summaries of the best evidence have made the task of searching much easier now through resources such as the Cochrane Collaboration, BMJ Clinical Evidence, Sense About Science and Evidence Updates.
In addition, sites worth visiting are patient.co.uk and nice.org.uk as well as some sites dedicated to particular conditions such as the Irish Cancer Society at cancer.ie. Dr Anthony Cummins gave a very useful talk on EBM recently in the RCSI mini-med series at iti.ms/1i4tTG3.
