EDITORIAL

The value of case studies

Ian R McWhinney

Case studies have played an important part in the annals of general practice - and indeed of clinical medicine. Jenner’s discovery of vaccination culminated in the demonstration of its effectiveness in a boy called James Phipps.’ Jenner’s case did not stand alone. His experiment came after years of meticulous observation of the skin infections of dairy workers, enabling him to make the crucial distinction be- tween cowpox, which conferred immunity to smallpox, and other infections, which did not. Thus, Jenner successfully integrated the concrete with the abstract, the particular with the general and lessons from individual cases with the theoretical principles derived from the collective.

Mackenzie’s research on heart disease in his practice was similarly based on case studies of patients he knew well and followed for many years. In the course of his ob- servations he was able to demonstrate in a single patient the onset of what he called paralysis of the auricles, known now as atrial fibrillation. In 1907 he wrote to a colleague: ‘take the case of Mrs Still who gave me the first notion of auricular paralysis in 1897’.’ As with Jenner, the case was the culmination of years of observation of patients with rheumatic heart disease and arrhythmia.

In her interviews with Scottish GP’s, Reid’ noted that some doctors were unable to think of general practice in any other way than their individual patients. I believe it is true to say that GPs tend to be concrete more than abstract thinkers. An actual case brings things alive for us in a way that aggregated data cannot do. We learn differently from individual cases. They stimulate the imagination, open up possibilities, provoke us, and perhaps disturb us. They fill in the gaps left by powerful generalisations, reminding us that every illness is unique in the same way. However, there are also pitfalls if we rely too much on the cases we re- member. To reflect on our care of patients with diabetes or hypertension we need to look at the aggregated data, as well as individual cases that may illustrate a principle. The tendency to concrete thinking puts us at variance with academic medicine and we do best if we can reconcile our natural tendency with a capacity to think in general terms about o u r patients and our community.

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tan K McNhinney, professor emeritus. Departwwiii of Family Medicine, The llnizwrsity of Western Ontario, Ixmion, Ontwo, C:tznildil. Address for correspondence: Centre for Stntlres in )..imtly Medicine, Suite 245, 100 CoNip Circle, London, Ontario Kb(; 4x8 , CmadLi. E-mud: irii2cwhin@uwct,ca.

Case studies, some of them book long, have made a notable contribution to scientific medicine, though nowadays often dismissed with that thoughtless term, ‘anecdotal.’ ‘We need,’ wrote Oliver Sacks, ‘in addition to conventional medicine, a medicine of a far profounder sort, based on the profoundest understanding of the organism and of the life’.‘ Empirical science is the key to one form of knowledge, the generalised knowledge that gives us power over nature; the key to wisdom, however, is the knowledge of particulars.

With its tradition of bedside teaching, medicine has always retained its focus on the individual patient. In the modern era, the clinicopathological conference has served as an educational tool and an illustration of a clinical method. Too often, however, the patient does not leap from the page as an individual. The patient’s family doctor is not usually present. On one occasion when he was present, there was an exchange between the GP and the professor of medicine, a clash of two world views that only an individual case could bring to life.’ We have yet to see case studies that will do for the patient-centred clinical method what the clinicopathological conference has done for differential diagnosis.

A case study - perhaps of an unexpected bad outcome - may be the trigger for quality assurance. In this issue, Mitchell et al. present a case study to focus attention on weaknesses in a healthcare system. The absence of a gatekeeper role enabled the patient to reject the advice of his general practitioner and make his own referral to a specialist. When using case studies to draw attention to weaknesses in a system, we need to be sure that the case is not an isolated instance of failure, but a true rep- resentation of a malfunctioning system. If we are thinking with a system perspective, we should also be aware that the point where a system fails is often a weakness due to failure in other parts of the system. A system is defined as, ‘a dynamic order of parts and processes standing in mutual interaction with each other’.h It is necessary, therefore, to examine all the parts and processes, especially the interactions between parts. One of the common failures in healthcare systems is in the interaction between the primary and secondary levels of care.

In the case of Mitchell et al., a patient’s non-compliance with his GP’s advice set in motion a series of events made possible by a system of open access to specialists. To us, it seems intuitively obvious that effectiveness and efficiency

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are both enhanced when there is a gatekeeper role for the primary care physician. Others will object on the grounds that GPs, like other physicians, make mistakes. In broad terms, our mistakes tend to be ‘false negatives’ whereas the errors of specialists tend to be ‘false positive^.'^ The jus- tification for the gatekeeper role is that healthy patients are prevented from coming in significant numbers to special- ists. Even with a well-functioning system, some mistakes will be made in both directions. The best system will be one in which the benefits outweigh the risks and in which fail-safe mechanisms are in place to minimise risk. The public will be justified in questioning limitations on their freedom, in demanding evidence of effectiveness and reassurance that our belief in gatekeeping is not self- serving. For patients, the freedom to change their family physician can provide some reassurance. There is already some good evidence in favour of gatekee~ing.~ However, as Starfield maintains, we do need more research on the need for referral and the role of free choice of the primary

care physician - from individual practices and from collaborative and system-wide studies.

Acknowledgement Acknowledgement to Joanna L Asuncion for preparing the manuscript.

References 1 Fisk D. Dr Jenner of Berkeley. London: Wm Heinemann, 1959:129. 2 Mair A. Sir James Mackenzie 1953-1927, General Practitioner.

Edinburgh Churchill Livingstone, 1973:146. 3 Reid M. Marginal Man: The identity dilemma of the academic general

practitioner. Symbolic Interaction 1982;5:325-42. 4 Sacks 0. Awakenings. London: Pan Books, 1973. 5 McWhinney I. A Textbook of General Practice. New York:Oxford

University Press, 1997:61-2. 6 Von Bertallanfy L. General System Theory. New York: George

Braziller, 1968. 7 Starfield B. Primary Care: Balancing Health Needs, Services and

Technology. New York: Oxford University Press, 1998.

EDITORIAL

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prescribing costs can allow money to be used more effectively in other areas of the healthcare system. We must, however, remember that these savings can be at the expense of a patient’s adherence to their prescribed medi- cation; possibly also at the expense of the quality of care; and possibly at the expense of inter-professional relation- ships. If we are to ensure that financial incentive schemes result in a net gain for the healthcare system, we must look very carefully at the whole picture, and not just that portion which is most pleasing to the eye.

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edition. London: Office of Health Economics, 2000. 2 The National Institute for Healthcare Management Research and

Educational Foundation. Prescription drug expenditures in 2000: the upward trend continues. Washington D C NIHCM Foundation, 2001.

3 Martin JP. Social aspects of prescribing. London: William Heinemann Ltd, 1957.

4 Mossialos E, Abel-Smith B. Cost-containment in the pharmaceutical sector in the EU member states. London: London School of Economics, 1996.

5 Ferriman A. Report suggests that NHS is unsustainable in present form. BMJ 1999;319:801.

6 Dowell JS, Snadden D, Dunbar JA. Changing to generic formulary: how one fundholding practice reduced prescribing costs. BMJ 1995;310:505-8.

7 Anon. Harmful effects of practice budgets. BMJ 1989;298:1316. 8 Smith LFP, Morrissy JR. Ethical dilemmas for general practitioners

under the UK new contract. J Med Ethics 1994;20:175-80. 9 Avery AJ, Rodgers S, Heron T, Crombie R, Whynes D, Pringle M,

et al. A prescription for improvement? An observational study to identify how general practices vary in their growth in prescribing

10 Schoffski 0. Consequences of implementing a drug budget for office- based physicians in Germany. Pharmucoeconomics 1996;lO (Suppl.2): s37-47.

11 Reebye RN, Avery AJ, van den Bosch WJHM, Aslam M, Nijholt A, van der Bij A. Exploring community pharmacists’ perceptions of their professional relationships with physicians in Canada and the Netherlands. IntJ Pharm Pract 1999;7:149-58.

12 Lambert L. Face and politeness in pharmacist-physician interaction. Soc Sci Med 1996;8:1189-98.

Costs. BMJ 2000;321:276-81.

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