Unwarranted variations in healthcare delivery: implications for academic medical centres

Professor Wennberg has delivered yet another call to the academic and
health policy communities about the challenges posed by healthcare
variation.(1) In general terms one cannot disagree that variations in
healthcare delivery raise issues of equity and appropriateness of care.
However there is also room for a note of caution about Wennberg’s strongly
stated position.

Wennberg is concerned that even after nearly 100 years of academic
medicine much practice is still empirically based, and he implies that
this represents a failure of academic medicine. But randomised controlled
trials are somewhat less than fifty years old: perhaps ‘evaluative
clinical sciences’ are a more recent innovation than he suggests.
Moreover, there is a growing literature which documents the judgement
aspects of medical practice. For example, Tanenbaum gives a particularly
clear account of the distinction between professional knowledge and
probabilistic knowledge, and the problems of applying evidence based rules
to decisions which are essentially the domain of professional
judgement.(2) Evaluative clinical sciences do have the potential to
improve quality of care, but findings should not be implemented in a black
and white fashion which also eliminates the benefits of freely exercised
professional judgement.

Although there is a very large literature which documents variation,
it is sometimes open to criticism. Not all studies are careful to take
random effects into account, and these can sometimes be surprisingly
large. Claims about the inappropriateness of variability where the
comparison is an intuitive expectation that rates should not vary across
areas must be treated with close scrutiny.

It is also worth noting that, while Wennberg shows that variation can
be associated with poor quality care, other researchers have reached more
cautious conclusions on this issue. Casparie has reviewed a number of
studies which examine the link between variability and inappropriate care,
concluding that the link is unproven.(3)

Healthcare variation is often intuitively surprising, and raises
questions about equity and appropriateness of care. But intuitive
surprise is not enough to justify wholesale change to clinical practice.
Wennberg is right to call for research and an informed response to the
phenomenon, but I would argue that the challenges posed by variation are
less clear cut than they appear in Wennberg’s account, and that the risks
of misapplying the ‘evaluative clinical sciences’ to clinical judgement
argue for a more cautious approach.

I do not have a competing interest

(1) Wennberg JE. Unwarranted variations in healthcare delivery:
implications for academic health centres BMJ 2002;325:961-4

(2) Tanenbaum SJ. Evidence and expertise: the challenge of the
outcomes movement to medical professionalism Academic Medicine
1999;74(7):757-63

(3) Casparie AF. The ambiguous relationship between practice
variation and appropriateness of care: an agenda for further research
Health Policy 1996;35(3):247-65