Het volume van chirurgische ingrepen en de impact ervan op ... - KCE

52 Volume Outcome KCE reports 113
5.2.6 Volume outcome relationship
5.2.6.1 Analysis by hospital
MORTALITY RATE, BY HOSPITAL
Figure 5.4 presents the funnel plot of the number of oesphagectomies and the 2-year
mortality (observed, i.e. without risk adjustment). The size of the point is proportional
to the number of hospitals with the same volume and the same outcome. The
horizontal line represents the overall 2-year mortality i.e. 44.7%. None of the hospitals
are outside the 99.8% limits of variability.
Figure 5.4: Oesophageal cancer surgery: Funnel plot of 2-year mortality rate,
by hospital
DESCRIPTION OF DIFFERENCES IN CHARACTERISTICS ACCORDING TO
THE VOLUME CATEGORY OF THE HOSPITAL
Table 5.9 presents the descriptive differences in case-mix in function of the volume of
oesophageal cancer procedures per hospital. The 70 centres have been divided into five
groups according to their annual volume of procedures. The cut off limits are somewhat
arbitrary, as they are not meant to divide the hospitals into five groups of equal size, but
to summarize the information and to differentiate the groups as well as possible. 2-year
mortality was 36% in lowest volume hospitals (1-2 procedures per year) and more than
40% in all other volume categories. There is no evidence that case mix is related to
volume since patients having surgery at high- and low-volume hospitals were very
similar with respect to age, gender and co morbidities (i.e. Charlson score). The
distribution of the tumour stage among the hospital categories is very heterogeneous
and difficult to summarize.