Outliers in Cardiac surgery
In recent times, clinical performance has almost become synonymous with
outcome measurement(4). What makes outliers in heart surgery
particularly intriguing is that the outcomes guiding quality metrics are
categorical and infrequent: namely mortality and major adverse
cardiovascular and cerebrovascular events (MACCE). Large registries,
with particular mention of the STS National Database in the US, are
developing which accumulate significant amounts of patient data and have
an inevitable role in defining key performance indicators.
When the standards of care are within the middle 95% of the bell-curve,
our culture briefly acknowledges the equilibrium and proceeds with a
practice of “maintenance”. Afterall, the majority lie in this region.
Yet, extreme performers at the lower end of the curve take a larger
share of the public and governance limelight. The Bristol Enquiry in the
UK is the most pertinent example from recent times where the outlier
detection method resulted in sizeable and justifiable repercussions(5).
The side-effect of this is a shift of quality improvement resources
towards poorly performing outliers which may lead to less efficient
overall improvement in a network of healthcare providers as a whole (6).
In fact, newer studies are suggesting that outlier detection using
outcomes analysis and the subsequent knee-jerk reward-punishment
strategies can be harmful, especially when involving blame(7).