Publications

BACKGROUND

As part of a broader effort aimed at improving hospital safety, a large coalition of employers, the Leapfrog Group, will soon require hospitals caring for their employees to meet volume standards for 5 high-risk surgical procedures. We estimated the potential benefits of full nationwide implementation of these volume standards. METHODS. Using data from Nationwide Inpatient Sample and other sources, we first estimated the total number of each of the 5 procedures-coronary-artery bypass graft, abdominal aortic aneurysm repair, coronary angioplasty, esophagectomy, and carotid endarterectomy-performed each year in hospitals in US metropolitan areas. (Leapfrog exempts hospitals in rural areas to avoid access issues.) We then projected the effectiveness of volume standards (in terms of relative risks of mortality) for each procedure using data from a published structured literature review.

RESULTS

With full implementation nationwide, the Leapfrog volume standards would save 2581 lives. Of the procedures, volume standards would save the most lives with coronary-artery bypass graft (1486), followed by abdominal aortic-aneurysm repair (464), coronary angioplasty (345), esophagectomy (168), and carotid endarterectomy (118). In our estimates of the number of lives saved, we considered assumptions about how many patients would be affected and the effectiveness of volume standards (ie, strength of underlying volume-outcome relationships with each procedure).

CONCLUSIONS

If the Leapfrog volume standards are successfully implemented, employers and health-care purchasers could prevent many surgical deaths by requiring hospital volume standards for high-risk procedures.

Background. Studies of medical admissions have questioned the validity of using claims data to adjust for preexisting medical conditions (comorbidities), but the impact of using comorbidities from claims data to risk-adjust mortality rates for high-risk surgery is not well characterized. The purpose of this study was to evaluate the relationship between comorbidities and mortality in administrative data in surgical populations and identify better risk-adjustment methods. Methods. Using the national Medicare database (1994-1997), we identified admissions for elective abdominal aortic aneurysm repair (140,577) and pancreaticoduodenectomy (10,530). We calculated the relative risk of mortality (adjusted for age, sex, race, and admission acuity) for 5 chronic conditions that are known (from clinical series) to increase the risk of postoperative mortality and are commonly used in claims-based risk-adjustment models. To explore the potential value of alternative risk-adjustment strategies, we examined relationships between surgical mortality and comorbidities using diagnosis codes identified from previous admissions. Results. Overall, in-hospital mortality for elective abdominal aortic aneurysm (AAA) repair and pancreaticoduodenectomy were 5.1% and 10.4%, respectively. For both procedures, 3 of the 5 comorbidities were associated with decreased risk of mortality: prior myocardial infarction (MI) [RR = 0.38; 95% confidence interval (CI), 0.33-0.43 for AAA; RR = 0.38; 95% CI, 0.21-0.69 for pancreaticoduodenectomy), malignancy (RR = 0.67; 95% CI, 0.59-0.76 for AAA; RR = 0.74; 95% CI, 0.45-1.21 for pancreaticoduodenectomy], and diabetes (RR = 0.76; 95% CI, 0.64-0.84 for AAA; RR = 0.59; 95% CI, 0.49-0.69 for pancreaticoduodenectomy). Using comorbidities identified from prior admissions increased the mortality risk estimates for prior MI (RR = 1.22; 95% CI, 1.08-1.38 for AAA; RR = 0.80; 95% CI, 0.49-1.30 for pancreaticoduodenectomy) and diabetes (RR = 1.41; 95% CI, 1.25-1.59 for AAA; RR = 0.94; 95% CI, 0.78-1.14 for pancreaticoduodenectomy). Conclusions. Because comorbidities coded on the index admission appear protective, incorporating them in risk-adjustment models for studies comparing surgical performance may penalize providers for taking care of sicker patients. When available, comorbidity information from prior hospitalizations may be more useful for risk adjustment.

BACKGROUND

In addition to lower operative mortality, patients undergoing selected cancer operations at high volume centers have improved longterm survival. We sought to determine the overall effect of hospital volume on life expectancy after cancer surgery.

STUDY DESIGN

We used a Markov decision analysis model to estimate life expectancy for patients undergoing resection for pancreatic, lung, or colon cancer. Model inputs included probabilities of operative mortality and longterm survival. For input data, we examined operative mortality (in-hospital or within 30 days) stratified by volume in over 400,000 patients undergoing resection for these three cancers using the national Medicare database (1994-1999). Risks of late mortality were abstracted from published studies (MEDLINE, 1966 to present) to model the effect of hospital volume on longterm survival. In analysis, we first calculated life expectancy for patients undergoing surgery at very low, low, medium, high, and very high volume hospitals. We then explored the effects of various regionalization strategies.

RESULTS

Life expectancy increased steadily with hospital volume for all three cancers. Life expectancy after pancreatic cancer resection increased linearly with hospital volume: from 1.9 years at very low volume centers to 3.6 years at very high volume centers. For lung cancer, life expectancy ranged from 5.4 to 6.6 years. Increases in life expectancy for colon cancer were not as dramatic: from 6.8 at very low volume hospitals to 7.4 years at very high volume hospitals. Differences in life expectancy across volume strata were largely attributable to differences in longterm survival, not operative mortality. From a policy perspective, regionalizing surgery for colon cancer would produce the greatest overall life-expectancy gains, but it would require moving most patients.

CONCLUSIONS

Patients aged 65 and older with pancreatic, lung, and colon cancer have substantially greater life expectancy after cancer resection at higher volume hospitals. Further work is needed to understand the mechanisms underlying differences in performance across hospitals in cancer care.

BACKGROUND

Although initiatives to regionalize cancer surgery are already under way, the relative importance of volume in cancer surgery is disputed.

HYPOTHESIS

We examined surgical mortality with 8 cancer resections in the US population to better quantify the influence of hospital volume.

METHODS

Using information from the all-payer Nationwide Inpatient Sample (1995-1997), we examined mortality with 8 cancer resections (N = 195 152). After dividing patients into 3 evenly sized volume groups based on hospital procedure volume (low, medium, and high), we used regression techniques to describe relationships between hospital volume and in-hospital mortality, adjusting for patient characteristics.

RESULTS

Trends toward lower operative risks at high-volume hospitals were observed for 7 of the 8 procedures. However, differences between low- and high high-volume hospitals were statistically significant for only 3 operations (esophagectomy, 15.0% vs 6.5%; pancreatic resection, 13.1% vs 2.5%; and pulmonary lobectomy, 10.1% vs 8.9%, respectively). Although they did not reach statistical significance, absolute differences in mortality between low- and high-volume hospitals were greater than 1% for the following 3 procedures: gastrectomy, 8.7% vs 6.9%; cystectomy, 3.6% vs 2.5%; and pneumonectomy, 10.6% vs 8.9%, respectively. Mortality reductions for nephrectomy and colectomy were small. In general, in terms of absolute differences in mortality, the effect of volume was greatest in elderly patients.

CONCLUSIONS

Operative mortality decreases with increasing hospital volume for several cancer resections. However, volume may be most important in patients who are older and at higher risk.

OBJECTIVE

Aimed at reducing surgical deaths, several recent initiatives have attempted to establish volume-based referral strategies in high-risk surgery. Although payers are leading the most visible of these efforts, it is unknown whether volume standards will also reduce resource use.

METHODS

We studied postoperative length of stay and 30-day readmission rate after 14 cardiovascular and cancer procedures using the 1994-1999 national Medicare database (total n = 2.5 million). We used regression techniques to examine the relationship between length of stay, 30-day readmission, and hospital volume, adjusting for age, gender, race, comorbidity score, admission acuity, and mean social security income.

RESULTS

Mean postoperative length of stay ranged from 3.4 days (carotid endarterectomy) to 19.6 days (esophagectomy). There was no consistent relationship between volume and mean length of stay; it significantly increased across volume strata for 7 of the 14 procedures and significantly decreased across volume strata for the other 7. Mean length of stay at very-low-volume and very-high-volume hospitals differed by more than 1 day for 6 procedures. Of these, the mean length of stay was shorter in high-volume hospitals for 3 procedures (pancreatic resection, esophagectomy, cystectomy), but longer for other procedures (aortic and mitral valve replacement, gastrectomy). The 30-day readmission rate also varied widely by procedure, ranging from 9.9% (nephrectomy) to 22.2% (mitral valve replacement). However, volume was not related to 30-day readmission rate with any procedure.

CONCLUSION

Although hospital volume may be an important predictor of operative mortality, it is not associated with resource use as reflected by length of stay or readmission rates.

Differential diagnosis of hypoglycemic patients should include insulinoma. Plasma insulin-to-glucose ratio greater than 0.3 or C-peptide levels of 2 nmol/L or greater suggest insulinoma. Abdominal CT scan can exclude metastatic disease and identify uncommonly large islet cell tumors, but has poor sensitivity for localizing insulinomas; transgastric endoscopic ultrasound is the most sensitive technique. Palpation combined with intraoperative ultrasound identifies most tumors at operation and gives vital information about surrounding structures. If no tumor is found, blind distal pancreatectomy should not be performed, and the patient should be referred to an endocrinologist or endocrine surgeon for diagnostic confirmation and further localization. Laparoscopy is a viable alternative to open tumor resection; laparoscopic ultrasound can facilitate localization and guide safe resection.

Since the first minimally invasive colon resection 15 years ago, laparoscopic colectomy has been implemented as techniques have evolved. Like the laparoscopic approach for other operations, minimally invasive colectomy has potential benefits of improved short-term outcomes. Questions have been raised, however, regarding its use for colorectal cancer resection. Until recently, it was unclear whether minimally invasive surgery for colonic malignancies would achieve adequate oncologic resection. This review provides an overview of laparoscopic colectomy and techniques and examines recent data from randomized, controlled trials that report the short- and long-term outcomes after laparoscopic colectomy for cancer.