Reproduced with permission from Australian PrescriberThe document attached has been archived with permission from the publisher/copyright holderJohn Marle

Marley, John Ernest

Australian Prescriber

Adelaide Research &amp; Scholarship

114Australian Prescriber Vol. 23 No. 6  2000In this issue…The new drugs reviewed in this issue have all beenassessed for safety and efficacy. Although a treatmentmay be efficacious, John Marley points out that it maynot be effective or efficient.Heart failure needs effective treatment, but there areoften difficulties in managing the condition. HenryKrum suggests some solutions to these therapeuticdilemmas. Peter Fletcher believes that beta blockers arethe solution for some patients, even though these drugswere once contraindicated in heart failure.While the cost-effectiveness of bisphosphonates may bequestioned, they do have a role in some patients with lowbone density, particularly postmenopausal women.John Martin and Vivian Grill inform us how the drugswork, while Peter Ebeling discusses their clinical use inosteoporosis.The most effective treatment may not be a drug. In hisarticle on panic disorder John Tiller tells us that cognitivebehaviour therapy helps many patients.  One of thesepatients is actor Garry McDonald who reveals how heovercame his anxiety.E D I T O R I A LEfficacy, effectiveness, efficiencyJohn Marley, Professor, Department of General Practice, University ofAdelaide, AdelaideIndex words: drug utilisation, cost-effectiveness, drugevaluation.(Aust Prescr 2000;23:114–5)How is it, that guidelines for treatment often seem unrelatedto the patient sitting in front of the doctor? Guidelines aremostly based on evidence gathered from randomised controlledtrials. These trials are very good at assessing efficacy – that is,can a treatment work? Despite this, trials are not withoutsubstantial biases. Many people may be screened before a feware chosen to be included in a study, yet the results of the studywill be applied to the very people who were excluded. Thepopulation studied in trials tends to be young, male, white,suffering from a single condition and using a single treatment.Most patients, at least in general practice, do not fit thisdescription. They often have multiple illnesses, take multiplemedications and are either too young or too old to have beenincluded in clinical trials. Perhaps we should accept a proposalto define efficacy in relation to medications as ‘the extent towhich a drug has the ability to bring about its intended effectunder ideal circumstances, such as in a randomised clinicaltrial’.*Efficacy is not the same as effectiveness.1 A treatment iseffective if it works in real life in non-ideal circumstances. Inreal life, medications will be used in doses and frequenciesnever studied and in patient groups never assessed in the trials.Drugs will be used in combination with other medications thathave not been tested for interactions, and by people otherthan the patient – the ‘over the garden fence’ syndrome.Effectiveness cannot be measured in controlled trials, becausethe act of inclusion into a study is a distortion of usual practice.Effectiveness can be defined as ‘the extent to which a drugachieves its intended effect in the usual clinical setting’.* Itcan be evaluated through observational studies of real practice.This allows practice to be assessed in qualitative as well asquantitative terms.2Australia is well suited to conduct observational studies becausewe have a high standard of relatively unrestricted practice andgood national databases, such as those held by the HealthInsurance Commission. These databases can be used forvalidating researchers’ separate database effectivenessstudies. In America there are very large patient databasesheld by the Health Maintenance Organisations. Their size isimpressive, but size is not everything. The data may have beencollected primarily for billing and they may be incomplete.Clinical practice is often governed by protocols, andmedications are limited to those supplied by the currentpreferred providers. The reimbursement mechanism for doctorsmay mean that they code conditions at the highest severitylevel. Patients belonging to one of these organisations may notrepresent the American population as a whole. In Britain, theGeneral Practice Research Database, compiled from practiceelectronic records, is very useful, especially for studies inpharmacoepidemiology. The British enjoy relativelyunrestricted clinical practice, but they do not have readilyusable national datasets against which to check the validityof their database studies.It is an irony that drugs are licensed for use almost exclusivelyon the results of controlled trials, yet they are withdrawn fromuse because of observational data that would not be acceptableto licensing authorities. Biases are present in observationalstudies, just as they are in trials, but they can be defined andoften controlled for, giving these studies a much greater valuethan that currently awarded to them.* From a suggested dictionary of pharmacoepidemiology byC. Ineke Neutel, University of Ottawa Institute on Health ofthe Elderly, Research Department, SCO Health Services.43 Bruyere Street, Ottawa CANADA K1N 5C8.115Australian Prescriber Vol. 23 No. 6  2000Efficiency depends on whether a drug is worth its cost toindividuals or society. The most efficacious treatment, basedon the best evidence, may not be the most cost-effectiveoption. It may not be acceptable to patients. In every country,rationing of health care is a reality. There is no country,however wealthy, that can afford to deliver all the health carepossible to the whole of its population at all times. Rationingmay be implicit or explicit, but it will happen. Goodeffectiveness and efficiency studies will make this rationingmore informed.Good practical guidelines, such as the Therapeutic Guidelinesseries, are clearly very important and extremely useful. Theycould be made even more relevant to the patient in front of thedoctor, by being less dependent on efficacy studies. We shouldmake more use of effectiveness and efficiency studies andabandon the censorship of the evidence drawn from them.R E F E R E N C E S1. Haynes B. Can it work? Does it work? Is it worth it? Br Med J 1999;319:652-3.2. Greenhalgh T. Is my practice evidence-based? Br Med J 1996;313:957-8.E-mail: john.marley@medicine.adelaide.edu.auLettersLetters, which may not necessarily be published in full, should be restricted to not more than 250 words. When relevant, comment on the letter is sought from the author.Due to production schedules, it is normally not possible to publish letters received in response to material appearing in a particular issue earlier than the second or thirdsubsequent issue.Prescribing by numbersEditor, – It was interesting to see an article on the numberneeded to treat (NNT) (Aust Prescr 2000;23:38). NNT isbetter than looking at relative risk reductions but NNT stilldoes not always give you a feel for the relevance of anintervention.I believe clinical decision-making needs to consider twonumbers. These are the paired absolute incidences.X = Event rate control (the outcome with placebo,or the outcome if you do nothing)Y = Event rate active (the outcome with treatment)Consider a room full of 100 people with a clinical problem.Put it to them, ‘Do nothing and the event will happen to X ofyou, and if all of you take the pill it will happen to Y of you.’Using the Helsinki Heart study as quoted in the article, howwould 100 men respond if told ‘Take gemfibrozil for fiveyears and 4.1 of you will have an event, do nothing and2.7 of you will have an event’? I suspect many would say whybother with treatment, but some would say OK.Clinical decision-making needs to be made in the context ofreal people. Other comorbidity, patient attitude, patientexpectations, the psychological burden of disease label,adverse effects, secondary costs (for example, more visits tothe doctor) all need consideration. I believe that by lookingat the two numbers (X and Y) I can get a better feel for therelevance of an intervention, and also inform my patientsabout ‘doing something’ versus ‘doing nothing’.I believe the treatment of risk and risk factors is greatlyoverrated, and that many are treated for risk without agenuine consideration of how much of a difference it couldmake for the individual. As the surgeons learn to withholdthe knife, I believe we should learn to hold back the drugtreatment of risk factors, not because there is no evidence, butbecause in the bigger picture it is irrelevant to the patient –this will be facilitated by looking at the X and Y numbers.Paul NeeskensGeneral PractitionerHervey Bay, QldMedicines and the mediaEditor, – The Australian Prescriber editorial (Aust Prescr2000;23:70–1) regarding reporting of medicines in the mediais timely. On 13 April 2000, an article in the Adelaide‘Advertiser’ included the headline ‘Accepted safe levels ofcholesterol “still too high”’ and pictured a young womanhaving a cholesterol test. The commentary continued,‘Worldwide evidence proved “normal” cholesterol levels inhealthy men and women were too high, an internationalauthority on heart disease said in Adelaide yesterday’. Thearticle went on to talk about ‘...a new ultra-low dosecholesterol-reducing drug called cerivastatin, ...recentlyapproved for use in Australia...’Assuming a new study had been released assessing healthoutcomes associated with cerivastatin, we contacted thereporter. He could not provide any information to supportthe story, but suggested we contact the Adelaide marketingcompany publicising the visit of the overseas specialist. Themarketing company supplied their media release, but couldnot provide a reference. They reported the media release wasredrafted from one produced by a Sydney company. TheSydney marketing company also could not provide areference. They said their media release was based oninformation supplied by Bayer, but they had returned allmaterial to Bayer.We rang Bayer on five occasions. The product manager wasnever available to speak to us, nor has he returned our call.The Adelaide marketing company, however, was moresympathetic. They rang us back to say the West of ScotlandCoronary Prevention Study, a 1995 study involvingpravastatin, was the basis for the story. Was the story ‘news’or advertising? How can consumers tell the difference?Libby Roughead andAndrew GilbertSchool of Pharmacy and Medical SciencesUniversity of South AustraliaAdelaide

Efficacy, effectiveness, efficiency

John Marley

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Efficacy, effectiveness, efficiency

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