In a study of 5,571 patients from the general surgery departments of 11
Israeli hospitals, the crude overall wound infection rates showed
interhospital heterogeneity. The rates ranged from 6.3% to 12.4%
(P(X2) = 0.039). Controlling
for the different distributions of procedures performed in the various
institutions did not reduce this variability. None of the hospitals had
either consistently high or consistently low infection rates. A hospital
could have low rates for one procedure and high rates for another.
Therefore, the decision was made to proceed with procedure-specific
analyses. This article details results of the analysis of 1,487 hernia
operations. Four variables (old age, infection at another site,
incarceration, and introduction of drains) accounted for almost all the
differences in infection rates among the institutions. Of the four, presence
of drains had the strongest association with infection (P derived from the
logistic model <0.001). The risk was consistent in all hospitals and was
unconfounded by other measurable factors. In contrast, the pattern of using
drains seemed arbitrary and inconsistent, ranging from 9% of patients in one
hospital to 41% in another. These findings were used as a basis for
discussion with the surgical teams and for the initiation of a randomized
clinical trial on the use of drains in hernia operations.