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

KCE Reports 113 Volume Outcome 213
VOLUME OUTCOME ASSOCIATION
Our results show that, after case-mix adjustment, hospitals with a higher volume of hip
fracture surgeries are not associated with lower in-hospital mortality (see Table 7.43).
The same accounts for surgeon volume (see Table 7.45).
Other studies did find an inverse relation between higher volumes and outcomes.
Nevertheless, the studies by Hughes and by Taylor were not suitable for comparison. 103,
309
First, their patient population was not analogous to ours: Hughes included hip
fracture patients that had no surgery as well as those with fractures of other (than the
neck) or unspecified parts of the femur; Taylor studied all patients who underwent a hip
procedure whether they had a hip fracture or not. Second, these studies did not adjust
for case-mix.
Wenning et al. found that patients in low-volume hospitals (less than 15 hip procedures
per year) were more at risk of dying postoperatively (odds ratio is 1.33; 95% CI 1.09,
1.63) compared to those in high-volume hospitals (more than 45 procedures per
year). 340 Shah et al. limited their study to patients >65 years of age with femoral neck
fracture undergoing hemi-arthroplasty (ICD-9-CM procedure code 81.52), in the USA
between 1988 and 2000. 341 He demonstrated that patients of low-volume surgeons (1
to 3 procedures per year) had an 18% (odds ratio 1.18; 95% CI 1.03, 1.34) increased
risk of mortality compared with patients treated by surgeons performing >12
procedures per year. Hospital volume, on the other hand, could not predict mortality.
Hamilton and colleagues, on the other hand, showed that fluctuations in a hospital’s
volume from period to period had no significant effect on mortality. 338
Although we did not find a volume outcome association, the logistic regressions showed
that male patients are almost two times more likely to die during the index admission
than female patients (odds ratio is 1.99 in Table 7.43 and 1.98 in Table 7.45). Holt et al.
reported similar gender differences in epidemiology and outcome after hip fracture. 342
Twenty-two percent of these patients was male, while 78% was female. Men had a
younger mean age at presentation (i.e. 77 years compared with 81 years for women).
Despite the fact that male patients were younger, they were in poorer pre-operative
health (i.e. men were more likely to be ASA 3 or above). Mortality at 30 and 120 days
was almost two times higher for men than for women, even after controlling for the
effects of case-mix variables.
Key points on volume outcome association for hip fracture surgery
(HFS)
• A total of 9 934 patients were hospitalized in 2004 for a fracture of the neck
of the femur and underwent a surgical intervention.
• These interventions were performed in 113 centres and by 675 surgeons.
Annual mean number of HFS was 88 per centre, and 15 per surgeon. These
volumes are much higher than US data (44% of centres less than 11 elective
HFS).
• In-hospital mortality is 6.5% after HFS. Logistic regression models were
fitted to assess association between this outcome and centre or surgeon
volume. Factors included in the models were: age, sex, Charlson score, and
principal diagnosis (ostheoarthrosis versus others diagnoses).
• Although the literature study concluded that there was an inverse relation
between hospital volume and mortality, in Belgian data neither hospital or
surgeon volume were associated with in-hospital mortality after HFS.
• Unfortunately, the MCD do not provide information on the outcomes of
greatest interest to patients such as loss of independence, loss of mobility or
residual pain.