INTRODUCTION: In a case controlled analysis, we attempted to determine if the volume-survival benefit persists in liver resection (LR) after eliminating differences in background characteristics. METHODS: Using the Nationwide Inpatient Sample (NIS), we identified all LR (n = 2,949) with available surgeon/hospital identifiers performed from 1998-2005. Propensity scoring adjusted for background characteristics. Volume cut-points were selected to create equal groups. A logistic regression for mortality was then performed with these matched groups. RESULTS: At high volume (HV) hospitals, patients (n = 1423) were more often older, white, private insurance holders, elective admissions, carriers of a malignant diagnosis, and high income residents (p < 0.05). Propensity matching eliminated differences in background characteristics. Adjusted in-hospital mortality was significantly lower in the HV group (2.6% vs. 4.8%, p = 0.02). Logistic regression found that private insurance and elective admission type decreased mortality; preoperative comorbidity increased mortality. Only LR performed by HV surgeons at HV centers was independently associated with improved in-hospital mortality (HR, 0.43; 95% CI, 0.22-0.83). CONCLUSIONS: A socioeconomic bias may exist at HV centers. When these factors are accounted for and adjusted, center volume does not appear to influence in-hospital mortality unless LR is performed by HV surgeons at HV centers.

OBJECTIVES: To develop a population-based risk score for stratifying patients by risk of in-hospital mortality following procedural intervention for hepatic neoplasm. BACKGROUND: There has been growing support for the value of surgical management of hepatic neoplastic disease, both primary and metastatic. Advances in surgical and ablative technologies have contributed to a decrease in the mortality associated with these procedures. However, multiple patient-, disease- and treatment-related factors can contribute to perioperative morbidity and mortality. METHODS: Using the Nationwide Inpatient Sample from 1998 to 2005, a retrospective cohort of patient-discharges for hepatic procedures with a concurrent diagnosis of hepatic primary or metastatic neoplasm to the liver was assembled. Procedures were categorized as lobectomy, wedge resection, or enucleation/ablation. Logistic regression and bootstrap methods were used to create an integer score for estimating the risk of in-hospital mortality using patient demographics, comorbidities, procedure type, tumor type, and hospital characteristics. A randomly selected sample of 80% of the cohort was used to create the risk score. Testing was conducted in the remaining 20% validation-set. RESULTS: In total, 12,969 patient-discharges were identified. Overall in-hospital mortality was 3.45%. Predictive characteristics incorporated into the model included: age, sex, Charlson comorbidity score, procedure type, hospital type, and type of neoplasm. Integer values were assigned to these, and used to calculate an additive score. Five clinically relevant groups were assembled to stratify risk, with a 36-fold gradient in mortality. Rates in the groups were as follows: 0.9%, 2.5%, 6.8%, 17.6%, and 35.9%. In the derivation set, as well as in the validation set, the simple score discriminated well, with c-statistics of 0.76 and 0.70, respectively. CONCLUSIONS: An integer-based risk score can be used to predict in-hospital mortality after hepatic procedure for neoplasm, and may be useful for preoperative risk stratification and patient counseling.

INTRODUCTION: Surgeon specialization has been shown to result in improved outcomes but may not be the sole measure of surgical quality in hepato-pancreatico-biliary (HPB) surgery. We attempted to determine which factors predominate in optimal patient outcomes between volume, surgeon, and hospital resources. METHODS: All non-transplant pancreatic (n = 7195) and liver operations (n = 4809) from the Nationwide Inpatient Sample (NIS) were examined from 1998-2005. Surgeons and hospitals were divided into two groups, transplant (TX) or non-transplant (non-TX), using the unique surgeon and hospital identifier of NIS. A logistic regression model examined the relationship between factors while accounting for patient and hospital factors. RESULTS: We identified 4,355 primary surgeons (165 TX, 4,190 non-TX) who performed HPB surgery in 675 hospitals across 12 different states. Non-TX surgeons performed the majority of pancreatic (97%) and liver procedures (81%). There was no difference in mortality after HPB surgery depending on surgeon specialty (p = 0.59). Factors for inpatient death after HPB surgery included increasing age, male gender, and public insurance (p < 0.05). In addition, surgery performed at a TX center had a 21% lower odds of perioperative mortality. DISCUSSION: Non-TX surgeons performed the majority of pancreatic and liver surgery in the US. Hospital factors like support of transplantation but not surgical specialty, appeared to impact operative mortality. Future regulatory benchmarks should consider these types of center-based facilities and resources to assess patient outcomes.