James Gibbs

Risk adjustment of the postoperative morbidity rate for the comparative assessment of the quality of surgical care : Results of the National Veterans Affairs Surgical Risk Study

BACKGROUND The National Veterans Affairs Surgical Risk Study was designed to collect reliable, valid data on patient risk and outcomes for major surgery in the Veterans Health Administration and to report comparative risk-adjusted postoperative mortality rates for surgical services in Veterans Health Administration. STUDY DESIGN This cohort study was conducted in 44 Veterans Affairs Medical Centers. Included were 87,078 major noncardiac operations performed under general, spinal, or epidural anesthesia between October 1, 1991, and December 31, 1993. The main outcomes measure was all-cause mortality within 30 days after the index procedure. Multivariable logistic regression risk-adjustment models for all operations and for eight surgical subspecialties were developed. Risk-adjusted surgical mortality rates were expressed as observed-to-expected ratios and were compared with unadjusted 30-day postoperative mortality rates. RESULTS Patient risk factors predictive of postoperative mortality included serum albumin level, American Society of Anesthesia class, emergency operation, and 31 additional preoperative variables. Considerable variability in unadjusted mortality rates for all operations was observed across the 44 hospitals (1.2-5.4%). After risk adjustment, observed-to-expected ratios ranged from 0.49 to 1.53. Rank order correlation of the hospitals by unadjusted and risk-adjusted mortality rates for all operations was 0.64. Ninety-three percent of the hospitals changed rank after risk adjustment, 50% by more than 5 and 25% by more than 10. CONCLUSIONS The Department of Veterans Affairs has successfully implemented a system for the prospective collection and comparative reporting of risk-adjusted postoperative mortality rates after major noncardiac operations. Risk adjustment had an appreciable impact on the rank ordering of the hospitals and provided a means for monitoring and potentially improving the quality of surgical care.

Relation of Surgical Volume to Outcome in Eight Common Operations : Results From the VA National Surgical Quality Improvement Program

OBJECTIVE To examine, in the Veterans Health Administration (VHA), the relation between surgical volume and outcome in eight commonly performed operations of intermediate complexity. SUMMARY BACKGROUND DATA In multihospital health care systems such as VHA, consideration is often given to closing low-volume surgical services, with the assumption that better surgical outcomes are achieved in hospitals with larger surgical volumes. Literature data to support this assumption in intermediate-complexity operations are either limited or controversial. METHODS The VHA National Surgical Quality Improvement Program data on nonruptured abdominal aortic aneurysmectomy, vascular infrainguinal reconstruction, carotid endarterectomy (CEA), lung lobectomy/pneumonectomy, open and laparoscopic cholecystectomy, partial colectomy, and total hip arthroplasty were used. Pearson correlation, analysis of variance, mixed effects hierarchical logistic regression, and automatic interaction detection analysis were used to assess the association of annual procedure/specialty volume with risk-adjusted 30-day death (and stroke in CEA). RESULTS Eight major surgical procedures (68,631 operations) were analyzed. No statistically significant associations between procedure or specialty volume and 30-day mortality rate (or 30-day stroke rate in CEA) were found. CONCLUSIONS In VHA hospitals, the procedure and surgical specialty volume in eight prevalent operations of intermediate complexity are not associated with risk-adjusted 30-day mortality rate from these operations, or with the risk-adjusted 30-day stroke rate from CEA. Volume of surgery in these operations should not be used as a surrogate for quality of surgical care.

Validating risk-adjusted surgical outcomes: site visit assessment of process and structure1

Abstract Background: Risk-adjusted mortality and morbidity rates are often used as measures of the quality of surgical care. This study was conducted to determine the validity of risk-adjusted surgical morbidity and mortality rates as measures of quality of care by assessing the process and structure of care in surgical services with higher-than-expected and lower-than-expected risk-adjusted 30-day mortality and morbidity rates. Study Design: A structural survey of 44 Veterans Affairs Medical Center surgical services and site visits to 20 surgical services with higher-than-expected and lower-than-expected risk-adjusted outcomes were conducted. Main outcome measures included assessment of technology and equipment, technical competence of staff, leadership, relationship with other services, monitoring of quality of care, coordination of work, relationship with affiliated institutions, and overall quality of care. Results: Surgical services with lower-than-expected risk-adjusted surgical morbidity and mortality rates had significantly more equipment available in surgical intensive care units than did services with higher-than-expected outcomes (4.3 versus 2.9, p Conclusions: Significant differences in several dimensions of process and structure of the delivery of surgical care are associated with differences in risk-adjusted surgical morbidity and mortality rates among 44 Veterans Affairs Medical Centers.

CD94-NKG2A receptors regulate antiviral CD8+ T cell responses

CD8+ T lymphocytes mediate immunosurveillance against persistent virus infections and virus-induced neoplasia. Polyoma virus, a highly oncogenic natural mouse DNA virus, establishes persistent infection, but only a few mice are highly susceptible to tumors induced by the virus. Mature antiviral CD8+ T cells expand in tumor-susceptible mice, but their cytotoxic effector activity is nonfunctional in vivo. Here we show that the natural killer cell inhibitory receptor, CD94-NKG2A, is up-regulated by antiviral CD8+ T cells during acute polyoma infection and is responsible for down-regulating their antigen-specific cytotoxicity during both viral clearance and virus-induced oncogenesis.

Comparison of Surgical Outcomes Between Teaching and Nonteaching Hospitals in the Department of Veterans Affairs

ObjectiveTo determine whether the investment in postgraduate education and training places patients at risk for worse outcomes and higher costs than if medical and surgical care was delivered in nonteaching settings. Summary Background DataThe Veterans Health Administration (VA) plays a major role in the training of medical students, residents, and fellows. MethodsThe database of the VA National Surgical Quality Improvement Program was analyzed for all major noncardiac operations performed during fiscal years 1997, 1998, and 1999. Teaching status of a hospital was determined on the basis of a background and structure questionnaire that was independently verified by a research fellow. Stepwise logistic regression was used to construct separate models predictive of 30-day mortality and morbidity for each of seven surgical specialties and eight operations. Based on these models, a severity index for each patient was calculated. Hierarchical logistic regression models were then created to examine the relationship between teaching versus nonteaching hospitals and 30-day postoperative mortality and morbidity, after adjusting for patient severity. ResultsTeaching hospitals performed 81% of the total surgical workload and 90% of the major surgery workload. In most specialties in teaching hospitals, the residents were the primary surgeons in more than 90% of the operations. Compared with nonteaching hospitals, the patient populations in teaching hospitals had a higher prevalence of risk factors, underwent more complex operations, and had longer operation times. Risk-adjusted mortality rates were not different between the teaching and nonteaching hospitals in the specialties and operations studied. The unadjusted complication rate was higher in teaching hospitals in six of seven specialties and four of eight operations. Risk adjustment did not eliminate completely these differences, probably reflecting the relatively poor predictive validity of some of the risk adjustment models for morbidity. Length of stay after major operations was not consistently different between teaching and nonteaching hospitals. ConclusionCompared with nonteaching hospitals, teaching hospitals in the VA perform the majority of complex and high-risk major procedures, with comparable risk-adjusted 30-day mortality rates. Risk-adjusted 30-day morbidity rates in teaching hospitals are higher in some specialties and operations than in nonteaching hospitals. Although this may reflect the weak predictive validity of some of the risk adjustment models for morbidity, it may also represent suboptimal processes and structures of care that are unique to teaching hospitals. Despite good quality of care in teaching hospitals, as evidenced by the 30-day mortality data, efforts should be made to examine further the structures and processes of surgical care prevailing in these hospitals.

Predictors of Change in Walking Velocity in Older Adults

OBJECTIVE: To determine factors that predict change in walking velocity in older people using a multivariate model.

Predictors of decline in manual performance in older adults

OBJECTIVE: To determine factors that predict decline in manual performance using a multivariate model of determinants of functional limitation.

The development of a clinical trial to determine if watchful waiting is an acceptable alternative to routine herniorrhaphy for patients with minimal or no hernia symptoms

BACKGROUND This article describes the development and implementation of a randomized clinical trial designed to answer the question: Is watchful waiting an acceptable alternative to operation for men with asymptomatic or minimally symptomatic inguinal hernias? STUDY DESIGN A clinical trial has been designed to compare watchful waiting and operation for men with an asymptomatic or a relatively asymptomatic inguinal hernia. Men are randomized to watchful waiting or a standard open operation, the Lichtenstein tension-free hernia repair, and are followed for a minimum of 2 years. The target sample size of 753 patients was chosen so that the trial would have power sufficiently high to detect a clinically meaningful difference between treatment groups in either of the two primary outcomes as measured at 2 years: pain or discomfort interfering with normal activities and the physical component summary score of the SF-36 health-related quality-of-life survey. The study was begun in five centers located in both community and academic environments. At 18 months, a sixth site was added and at 28 months, after enrollment of 145 patients, one of the centers was terminated for reasons related to inadequate followup; all data from this center were deleted. As a routine measure, an independent experienced trial manager audited all clinical sites. RESULTS Enrollment of patients began in January 2000 and will end on December 31, 2002. As of November 1, 2002, 637 patients had been randomized, 85% of the target enrollment. An additional 2,115 patients were screened but not randomized, yielding a recruitment rate of 23.1%. Analysis and publication of the results of the study will take place on completion of the minimum 2-year followup period for all patients. CONCLUSIONS A trial to compare the outcomes of watchful waiting and operation for management of inguinal hernias in men is needed to provide data to surgeons and to patients that can aid in choice of treatment. A description of the design of such a trial is presented.

Tension-free inguinal hernia repair: the design of a trial to compare open and laparoscopic surgical techniques

BACKGROUND Inguinal hernia is a common condition in men and represents a large component of health-care expenditures. Approximately 700,000 herniorrhaphies are performed each year in the United States. The most effective method of repair of an inguinal hernia is not known. STUDY DESIGN A multicenter, randomized, clinical trial was designed to compare open tension-free inguinal hernia repair with laparoscopic tension-free repair on recurrence rates, complications, patient-centered outcomes, and cost. The study design called for randomization of 2,200 men over a period of 3 years. These men will be followed for a minimum of 2 years. This will allow determination of as little as a 3% absolute difference in recurrence rates with 80% power. Randomization is stratified by hospital, whether the hernia is unilateral or bilateral and whether the hernia is primary or recurrent. RESULTS This is a report of the study design and current status. The study involves 14 Veterans Affairs medical centers with previous experience in laparoscopic hernia repair. After 35 months of enrollment, 2,165 men were randomized and recruitment was then closed. The majority of the patients (82.3%) had unilateral hernias and 90.6% of the hernias were primary. Sixty-seven percent of the patients had an outpatient operation. CONCLUSIONS We report successful recruitment into a large multicenter trial comparing open and laparoscopic hernia repair. When followup is complete, this study will provide data regarding both clinical (recurrence rates) and patient-centered outcomes.

Joint impairment and ambulation in the elderly

Objective: To test the impact of joint impairment on ambulation in the elderly, using a multivariate model.