Background. Several studies have reported lower perioperative mortality rat
es with pancreaticoduodenectomy at high-volume hospitals than at low-volume
hospitals. We sought to determine whether volume is also related to surviv
al after hospital discharge.
Methods, Using information from the Medicare claims database, we performed
a retrospective cohort study of all 7229 patients over age 65 undergoing pa
ncreaticoduodenectomy in the United States between 1992 and 1995. We divide
d the study population into approximate quartiles according to their hospit
al's average annual volume of pancreaticoduodenectomy in Medicine patients:
very low (<1/y), low (1-2/y), medium (2-5/y), and high (5+/y). To adjust f
or potentially confounding variables, we used a Cox proportional hazards mo
del to examine relationships between hospital volume and mortality, our pri
mary outcome measure.
Results. Overall, 3-year survival was higher at high-volume centers (37%) t
han at medium- (29%), low- (26%), and very low volume hospitals (25%) (log-
rank P < .0001). After excluding perioperative deaths and adjusting for cas
e-mis patients undergoing surgery at high-volume hospitals remained less li
kely to experience late mortality than patients at very low volume centers
(adjusted hazard ratio 0.69, 95% CI 0.62-0.76). Relationships between hospi
tal volume and survival after discharge were not ? restricted to patients w
ith cancer diagnoses, patients with benign disease had similar improvements
in late survival after surgery at high-volume centers.
Conclusions. Hospital volume strongly influences both perioperative risk an
d long-tnm survival after pancreaticoduodenectomy. Our data suggest that bo
th patient selection and differences in quality of care may underlie better
outcomes at high-volume referral centers.