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J D Birkmeyer

Publications and source records attributed to J D Birkmeyer.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cost-effectiveness of cardioversion and antiarrhythmic therapy in nonvalvular atrial fibrillation.

BACKGROUND: Physicians managing patients with nonvalvular atrial fibrillation must consider the risks, benefits, and costs of treatments designed to restore and maintain sinus rhythm compared with those of rate control with antithrombotic prophylaxis. OBJECTIVE: To compare the cost-effectiveness of cardioversion, with or without antiarrhythmic agents, with that of rate control plus warfarin or aspirin. DESIGN: A Markov decision-analytic model was designed to simulate long-term health and economic outcomes. DATA SOURCES: Published literature and hospital accounting information. TARGET POPULATION: Hypothetical cohort of 70-year-old patients with different baseline risks for stroke. TIME HORIZON: 3 months. PERSPECTIVE: Societal. INTERVENTION: Therapeutic strategies using different combinations of cardioversion alone, cardioversion plus amiodarone or quinidine therapy, and rate control with antithrombotic treatment. OUTCOME MEASURES: Expected costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness. RESULTS OF BASE-CASE ANALYSIS: Strategies involving cardioversion alone were more effective and less costly than those not involving this option. For patients at high risk for ischemic stroke (5.3% per year), cardioversion alone followed by repeated cardioversion plus amiodarone therapy on relapse was most cost-effective ($9300 per QALY) compared with cardioversion alone followed by warfarin therapy on relapse. This strategy was also preferred for the moderate-risk cohort (3.6% per year), but the benefit was more expensive ($18,900 per QALY). In the lowest-risk cohort (1.6% per year), cardioversion alone followed by aspirin therapy on relapse was optimal. RESULTS OF SENSITIVITY ANALYSIS: The choice of optimal strategy and incremental cost-effectiveness was substantially influenced by the baseline risk for stroke, rate of stroke in sinus rhythm, efficacy of warfarin, and costs and utilities for long-term warfarin and amiodarone therapy. CONCLUSIONS: Cardioversion alone should be the initial management strategy for persistent nonvalvular atrial fibrillation. On relapse of arrhythmia, repeated cardioversion plus low-dose amiodarone is cost-effective for patients at moderate to high risk for ischemic stroke.

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PubMed1999

Trends in rates of reexploration for hemorrhage after coronary artery bypass surgery. Northern New England Cardiovascular Disease Study Group.

BACKGROUND: While mortality rates associated with coronary artery bypass grafting (CABG) have been declining, it is unknown whether similar improvements in the rates of morbidity have been occurring. This study examines trends in reexploration rates for hemorrhage, one of the serious complications of CABG surgery. It also explores changes in patient characteristics and several surgeon practice patterns potentially related to bleeding risks that may explain variations in these rates. METHODS: We performed a regional observational study of all of the 12,555 consecutive patients undergoing isolated CABG surgery in northern New England between 1992 and 1997. The rates of reexploration and patient characteristics were examined between two time intervals: period I (January 1, 1992 to June 1, 1994) and period II (June 1, 1995 to March 31, 1997). All of the region's 23 practicing surgeons responsible for these patients were surveyed to assess changes in practice patterns potentially related to bleeding risks. RESULTS: The adjusted rates of reexploration for bleeding declined 46% between periods I and II (3.6% versus 2.0%, p < 0.001). All of the five cardiac centers in northern New England showed similar trends with adjusted risk reductions ranging from 32% to 48% between the two time periods. This decline occurred despite the patients in period II having higher percentages of risk factors for reexploration for bleeding compared to patients in period I. From the surgeon survey, the number of surgeons using antifibrinolytics markedly increased from period I to period II. More surgeons were also using preoperative aspirin and heparin up until the time of surgery in period II. CONCLUSIONS: Similar to the rates of mortality, the rates of reexploration for bleeding following CABG surgery are substantially declining. This decrease in the reexploration rates occurred despite higher patient risks.

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PubMed1999

Should endovascular surgery lower the threshold for repair of abdominal aortic aneurysms?

PURPOSE: Because endovascular repair of abdominal aortic aneurysms (AAAs) is less invasive, some investigators have suggested that this increasingly popular technique should broaden the indications for elective AAA repair. The purpose of this study was to calculate quality-adjusted life expectancy rates after endovascular and open AAA repair and to estimate the optimal diameter for elective AAA repair in hypothetical cohorts of patients at average risk and at high risk. METHODS: A Markov decision analysis model was used in this study. Assumptions were made on the basis of published reports and included the following: (1) the annual rupture rate is a continuous function of the AAA diameter (0% for <4 cm, 1% for 4.5 cm, 11% for 5.5 cm, and 26% for 6.5 cm); (2) the operative mortality rate is 1% for endovascular repair (excluding the risk of conversion to open repair) and 3.5% for open repair at age 70 years; and (3) immediate endovascular-to-open conversion risk is 5%, and late conversion rate is 1% per year. The main outcome measure in this study was the benefit of AAA repair in quality-adjusted life years (QALYs). The optimal threshold size (the AAA diameter at which elective repair maximizes benefit) was measured in centimeters. RESULTS: The benefit of endovascular repair is consistently greater than that of open repair, but the additional benefit is small-0.1 to 0.4 QALYs. For men in average health with gradually enlarging AAAs with initial diameters of 4 cm, endovascular surgery reduces the optimal threshold diameter by very little: from 4.6 to 4.6 cm (no change) at age 60 years, from 4.8 to 4.7 cm at age 70 years, and from 5.1 to 4.9 cm at age 80 years. For older men in poor health, endovascular surgery reduces the optimal threshold diameter substantially (8.1 to 5.7 cm at age 80 years), but the benefit of repair in this population is small (0.2 QALYs). CONCLUSION: For most patients, the indications for AAA repair are changed very little by the introduction of endovascular surgery. Only for older patients in poor health does endovascular surgery substantially lower the optimal threshold diameter for elective AAA repair.

Age Factors↗
PubMed1999

Patient preferences for location of care: implications for regionalization.

BACKGROUND: Regionalization of high-risk surgical procedures to selected high-volume centers has been proposed as a way to reduce operative mortality. For patients, however, travel to regional centers may be undesirable despite the expected mortality benefit. OBJECTIVE: To determine the strength of patient preferences for local care. DESIGN: Using a scenario of potentially resectable pancreatic cancer and a modification of the standard gamble utility assessment technique, we determined the level of additional operative mortality risk patients would accept to undergo surgery at a local rather than at a distant regional hospital in which operative mortality was assumed to be 3%. We used multiple logistic regression to identify predictors of willingness to accept additional risk. SUBJECTS: One hundred consecutive patients (95% male, median age 65) awaiting elective surgery at the Veterans Affairs Medical Center in White River Jct., VT. MAIN OUTCOME MEASURE: Additional operative mortality risk patients would accept to keep care local. RESULTS: All patients preferred local surgery if the operative mortality risk at the local hospital were the same as the regional hospital (3%). If local operative mortality risk were 6%, which is twice the regional risk, 45 of 100 patients would still prefer local surgery. If local risk were 12%, 23 of 100 patients would prefer local surgery. If local risk were 18%, 18 of 100 patients would prefer local surgery. Further increases in local risk did not result in large changes in the proportion of patients preferring local care. CONCLUSIONS: Many patients prefer to undergo surgery locally even when travel to a regional center would result in lower operative mortality risk. Therefore, policy makers should consider patient preferences when assessing the expected value of regionalizing major surgery.

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PubMed1999

Effect of hospital volume on in-hospital mortality with pancreaticoduodenectomy.

BACKGROUND: Reports of better results at national referral centers than at low-volume community hospitals have prompted calls for regionalizing pancreaticoduodenectomy (the Whipple procedure). We examined the relationship between hospital volume and mortality with this procedure across all US hospitals. METHODS: Using information from the Medicare claims database, we performed a national cohort study of 7229 Medicare patients more than 65 years old undergoing pancreaticoduodenectomy between 1992 and 1995. We divided the study population into approximate quartiles according to the hospital's average annual volume of pancreaticoduodenectomies in Medicare patients: very low (< 1/y), low (1-2/y), medium (2-5/y), and high (5+/y). Using multivariate logistic regression to account for potentially confounding patient characteristics, we examined the association between institutional volume and in-hospital mortality, our primary outcome measure. RESULTS: More than 50% of Medicare patients a undergoing pancreaticoduodenectomy received care at hospitals performing fewer than 2 such procedures per year. In-hospital mortality rates at these low- and very-low-volume hospitals were 3- to 4-fold higher than at high-volume hospitals (12% and 16%, respectively, vs 4%, P < .001). Within the high-volume quartile, the 10 hospitals with the nation's highest volumes had lower mortality rates than the remaining high-volume centers (2.1% vs 6.2%, P < .01). The strong association between institutional volume and mortality could not be attributed to patient case-mix differences or referral bias. CONCLUSIONS: Although volume-outcome relationships have been reported for many complex surgical procedures, hospital experience is particularly important with pancreaticoduodenectomy. Patients considering this procedure should be given the option of care at a high-volume referral center.

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PubMed1999

Relationship between hospital volume and late survival after pancreaticoduodenectomy.

BACKGROUND: Several studies have reported lower perioperative mortality rates with pancreaticoduodenectomy at high-volume hospitals than at low-volume hospitals. We sought to determine whether volume is also related to survival 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 pancreaticoduodenectomy in the United States between 1992 and 1995. We divided the study population into approximate quartiles according to their hospital's average annual volume of pancreaticoduodenectomies in Medicare patients: very low (< 1/y), low (1-2/y, medium (2-5/y), and high (5+/y). To adjust for potentially confounding variables, we used a Cox proportional hazards model to examine relationships between hospital volume and mortality, our primary outcome measure. RESULTS: Overall, 3-year survival was higher at high-volume centers (37%) than at medium- (29%), low- (26%), and very low volume hospitals (25%) (log-rank P < .0001). After excluding perioperative deaths and adjusting for case-mix, patients undergoing surgery at high-volume hospitals remained less likely to experience late mortality than patients at very low volume centers (adjusted hazard ratio 0.69, 95% CI 0.62-0.76). Relationships between hospital volume and survival after discharge were not restricted to patients with 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 and long-term survival after pancreaticoduodenectomy. Our data suggest that both patient selection and differences in quality of care may underlie better outcomes at high-volume referral centers.

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PubMed1998

Reexploration for hemorrhage following coronary artery bypass grafting: incidence and risk factors. Northern New England Cardiovascular Disease Study Group.

OBJECTIVE: To assess mortality and risk factors associated with reexploration for hemorrhage in patients undergoing coronary artery bypass grafting (CABG). DESIGN: Regional cohort study. Patient characteristics, treatment variables, and outcome measures were collected prospectively. SETTING: All 5 centers performing cardiac surgery in Maine, New Hampshire, and Vermont. PATIENTS: A consecutive cohort of 8586 patients undergoing isolated CABG between 1992 and 1995. MAIN OUTCOME MEASURES: Postoperative hemorrhage leading to reexploration, in-hospital mortality, and length of stay. RESULTS: A total of 305 patients (3.6%) underwent reexploration for bleeding. In these patients, in-hospital mortality was nearly 3 times higher (9.5% vs 3.3% for patients not requiring reoperation, P<.001) and average length of stay from surgery to discharge was significantly longer (14.5 days vs 8.6 days, P<.001). High rates of reexploration for hemorrhage were observed in patients with prolonged (> 150 minutes) cardiopulmonary bypass (39 [11.1%] of 351) and in those requiring an intra-aortic balloon pump intraoperatively (12 [8%] of 139). In multivariate analysis, older age, smaller body surface area, prolonged cardiopulmonary bypass, and number of distal anastomoses were associated with increased bleeding risks. The use of thrombolytic therapy within 48 hours of surgery was weakly but not significantly associated with the need for reexploration. Factors not significantly associated with reexploration included patient sex, preoperative ejection fraction, surgical priority, history of liver disease, myocardial infarction, prior CABG, renal failure, and diabetes mellitus. CONCLUSIONS: Hemorrhage requiring reexploration after CABG is associated with markedly increased mortality and length of stay. Patients predicted to have increased risks of bleeding may benefit from prophylactic use of aprotinin, aminocaproic acid, or other agents shown to reduce hemorrhage.

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PubMed1998

Results of a regional study of modes of death associated with coronary artery bypass grafting. Northern New England Cardiovascular Disease Study Group.

BACKGROUND: It is well known that surgeon-specific in-hospital mortality rates for coronary artery bypass grafting vary, but this aggregate measure does not suggest specific opportunities for improvement. METHODS: We performed a regional prospective study of 8,641 consecutive patients undergoing isolated coronary artery bypass grafting by all of the 23 cardiothoracic surgeons practicing in northern New England during the study period. Mode of death was assigned by an end points committee using predetermined definitions. Surgeons were ranked according to risk-adjusted mortality rates and grouped in terciles, and cause-specific mortality rates were determined. RESULTS: The mortality rate was 3.3% in the lowest surgeon mortality tercile and 5.8% in the highest tercile. Fatal heart failure accounted for 80.0% of the difference in aggregate mortality rates, ranging from 1.9% in lowest surgeon mortality tercile to 4.0% in the highest tercile (p < 0.001). Rates of other causes did not differ significantly across surgeon mortality terciles. Differences in rates of fatal heart failure could not be explained by differences in preoperative left ventricular dysfunction or other patient characteristics. CONCLUSIONS: Most of the difference in observed mortality rates across surgeons is attributable to differences in rates of heart failure.

Cause of Death↗
PubMed1998

Cost-effectiveness analysis in surgery.

BACKGROUND: With tighter constraints on health care spending, many recognize the need to identify and restrict clinical interventions that are not cost-effective. As a result, cost-effectiveness analysis is being used increasingly to assess the relative value of surgical interventions. METHODS AND RESULTS: We first present the general concept of cost-effectiveness analysis and review a recent study of carotid endarterectomy to demonstrate the technique. We next consider the classic application of cost-effectiveness analysis to resource-allocation decisions and use the Oregon Medicaid experiment to illustrate some potential problems with this approach. We then present the current role of cost-effectiveness analysis: informing decisions about individual interventions that are new, controversial, or in direct competition with an accepted alternative treatment. Finally, we review several limitations of the methods used to measure costs and benefits and discuss problems with the interpretation of cost-effectiveness studies. CONCLUSIONS: Cost-effectiveness analysis is a systematic approach to assessing the relative value of health care interventions. This technique is being used increasingly to frame clinical policy decisions in surgery. Because of this, surgeons need to understand cost-effectiveness analysis and be prepared to examine these studies critically.

Cost-Benefit Analysis↗
PubMed1998

Variation profiles of common surgical procedures.

BACKGROUND: Rates of many surgical procedures vary widely across both large and small geographic regions. Although variation in health care use has long been described, few studies have systematically compared variation profiles across surgical procedures. The goal of this study was to examine current patterns of regional variation in the rates of common surgical procedures. METHODS: The study population consisted of patients enrolled in Medicare in 1995, excluding those enrolled in risk-bearing health maintenance organizations. Patients ranged in age from 65 to 99 years. Using data from hospital discharge abstracts, we calculated rates of 11 common inpatient procedures for each of 306 US hospital referral regions (HRRs). To assess the relative variability of each procedure, we determined the number of low and high outlier regions (HRRs with rates < 50% or > 150% the national average) and the ratio of highest to lowest HRR rates. RESULTS: Procedures differed markedly in their variability. Rates of hip fracture repair, resection for colorectal cancer, and cholecystectomy varied only 1.9- to 2.9-fold across HRRs (0, 0, and 4 outlier regions, respectively). Coronary artery bypass grafting, transurethral prostatectomy, mastectomy, and total hip replacement had intermediate variation profiles, varying 3.5- to 4.7-fold across regions (8, 10, 16, and 17 outlier regions, respectively). Lower extremity revascularization, carotid endarterectomy, back surgery, and radical prostatectomy had the highest variation profiles, varying 6.5- to 10.1-fold across HRRs (25, 32, 39, and 56 outlier regions, respectively). CONCLUSIONS: Although the use of many surgical procedures varies widely across geographic areas, rates of "discretionary" procedures are most variable. To avoid potential overuse or underuse, efforts to increase consensus in clinical decision making should focus on these high variation procedures.

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PubMed1997

Safety of the blood supply in the United States: opportunities and controversies.

The risk for viral transmission by transfusion has been reduced dramatically through improved techniques for selecting and testing blood donors. Initiatives to further improve the safety of the blood supply, including more stringent donor qualifications, additional testing for infectious disease markers, viral inactivation processes, and refinement of transfusion decisions, are possible. However, because the risk for viral transmission by allogeneic transfusion is already low, additional measures will have limited yield and poor cost-effectiveness. Furthermore, unexpected side effects of some of these "improvements" may reduce the safety of the blood supply by introducing new risks. Cost-effectiveness analyses of blood safety initiatives have highlighted such successes as the introduction of virus-specific assays for screening donated blood and have identified other interventions that have poor cost-effectiveness estimates. They have also quantitated the threshold level at which the risks of an intervention outweigh its benefits. These analyses have had little effect on decisions about blood safety, possibly because of overwhelming fear of AIDS and difficulties in applying cost-effectiveness estimates to a politically and emotionally charged issue. Future interventions for improving blood supply safety must be evaluated thoroughly and chosen carefully so that the intended goals are met. Communication with the public should be undertaken so that the public understands that some of the desired measures may result in inefficient allocation of health care resources.

Blood Donors↗
PubMed1997

Cost-effectiveness of carotid endarterectomy in asymptomatic patients.

PURPOSE: The purpose of this study was to determine the cost-effectiveness of carotid endarterectomy for treating asymptomatic patients with > or = 60% internal carotid stenosis, based on outcomes reported in the Asymptomatic Carotid Atherosclerosis Study (ACAS). METHODS: A cost-effectiveness analysis was performed using a Markov decision model in which the probabilities for base-case analysis (average age, 67 years; 66% male; perioperative stroke plus death rate, 2.3%; ipsilateral stroke rate during medical management, 2.3% per year) were based on ACAS. The model assumed that patients who had TIAs or minor strokes during medical management crossed over to surgical treatment, and used the NASCET data to model the outcome of these now-symptomatic patients. Average cost of surgery ($8500), major stroke ($34,000 plus $18,000 per year), and other costs were based on local cost determinations plus a review of the published literature. Cost-effectiveness was calculated as the incremental cost of surgery per quality-adjusted life year (QALY) saved when compared with medical treatment, discounting at 5% per year. Sensitivity analysis was performed to determine the impact of key variables on cost-effectiveness. RESULTS: In the base-case analysis, surgical treatment improved quality-adjusted life expectancy from 7.87 to 8.12 QALYs, at an incremental lifetime cost of $2041. This yielded an incremental cost-effectiveness ratio of $8,000 per QALY saved by surgical compared with medical treatment. The high cost of care after major stroke during medical management largely offset the initial cost of endarterectomy in the surgical group. Furthermore, 26% of medically managed patients eventually underwent endarterectomy because of symptom development, which also decreased the cost differential. Sensitivity analysis demonstrated that the relative cost of surgical treatment increased substantially with increasing age, increasing perioperative stroke rate, and decreasing stroke rate during medical management. CONCLUSION: For the typical asymptomatic patient in ACAS with > or = 60% carotid stenosis, our results indicate that carotid endarterectomy is cost-effective when compared with other commonly accepted health care practices. Surgery does not appear cost-effective in very elderly patients, in settings where the operative stroke risk is high, or in patients with very low stroke risk without surgery.

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PubMed1997

Value and cost-effectiveness of screening blood donors for antibody to hepatitis B core antigen as a way of detecting window-phase human immunodeficiency virus type 1 infections. The HIV Blood Donor Study Group.

BACKGROUND: The value of screening donors for antibody to hepatitis B core antigen (anti-HBc) for the prevention of posttransfusion hepatitis has declined markedly. However, anti-HBc screening may still be useful as a surrogate marker for the window period (WP) of human immunodeficiency virus type 1 (HIV-1) infection. STUDY DESIGN AND METHODS: First, the relationship between anti-HBc reactivity and HIV-1 WP infections was examined among 225 donors who had seroconverted to anti-HIV-1 positivity between 1987 and 1990. In addition, data from 1654 HIV-1 seropositive donors were analyzed to characterize the relationship among anti-HBc reactivity, donor demographics, and HIV-1-related risk factors. The yield and cost-effectiveness of anti-HBc for HIV-1 prevention were then projected on the basis of a published decision analysis model. RESULTS: Forty (18%) of 225 HIV-1-seroconverting donors tested anti-HBc-reactive on the donation preceding anti-HIV-1 seroconversion; in contrast, 341 (34%) of 1014 HIV-1-seropositive donors interviewed tested anti-HBc-reactive (chi-square test; p < 0.001). Anti-HBc reactivity was more common among HIV-1-seropositive donors reporting male-to-male sexual contact (169/360, 47%) and injection drug use (44/83, 53%) than among those with heterosexual contacts known to be HIV-1-positive (31/190, 16%) or transfusion exposure (3/21, 14%) or among females with no identified risk factors (21/124, 17%). The estimates of 18 to 34 percent sensitivity for anti-HBc in detecting HIV-1 WP donations and a current rate of 1 in 676,000 HIV-1 WP donations (after p24 antigen screening) suggest that continued use of anti-HBc screening could result in the transfusion of 5 to 12 fewer HIV-1-infected units per year in the United States, which would add 19 to 48 quality-adjusted years of life for the 3.5 million annual transfusion recipients at a cost of $992,020 to $2,345,000 per quality-adjusted life-year saved. CONCLUSION: The low yield and very poor cost-effectiveness of anti-HBc screening indicate that this test is not an effective screening test for HIV-1 WP donations.

Blood Donors↗