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Biomedical subjects

F A Sonnenberg

Publications and source records attributed to F A Sonnenberg.

At least 19 recordsLinked to original sources
PubMed2006

Optimal medical therapy is superior to transplantation for the treatment of class I, II, and III heart failure: a decision analytic approach.

BACKGROUND: The survival benefit of heart transplantation (HT) compared with optimal medical therapy (OMT) has never been tested. METHODS AND RESULTS: We created a decision analytic model that simulates a randomized clinical trial of OMT versus HT for each New York Heart Association (NYHA) class. The simulation calculates average life expectancy. The following assumptions were made for OMT annual mortality: class I no excess mortality from HF; class II and III based on MERIT-HF are 5.3% and 8.1%. Class IV is 12.8%, based on COPERNICUS. HT mortality rates were based on survival curves for HT 1982 to 2001. For classes I, II, and III, OMT demonstrated a life expectancy gain of 113 months (232+/-2.2 versus 119+/-2.1), 38 months (152+/-2.1 versus 114+/-2.1), and 6 months (117+/-1.8 versus 111+/-2.2), respectively, over HT. Class IV favored HT with a life expectancy gain of 26 months (107+/-2.1 versus 81+/-1.4) over OMT. Sensitivity analysis revealed if improvement in OMT decreased mortality by 38% for class IV patients, OMT and HT would have equivalent life expectancies. If improvement in HT resulted in a 7% increase in post-HT survival, OMT and HT would be equivalent for class III patients. If improvement in HT resulted in a 30% increase in post-HT survival, OMT and HT would be equivalent for class II patients. CONCLUSIONS: Our model predicts that currently, OMT is superior to HT for classes I, II, and III, but HT is superior for class IV. However, future advances in OMT or HT may change the relative benefits of these treatment modalities.

Adrenergic beta-Antagonists↗
PubMed2006

Computer-interpretable clinical practice guidelines. Where are we and where are we going ?

OBJECTIVES: To provide a comprehensive overview of computer-interpretable guideline (CIG) systems aimed at non-experts. The overview includes the history of efforts to develop CIGs, features of and relationships among current major CIG systems, current status of standards developments pertinent to CIGs and identification of unsolved problems and needs for future research. METHODS: Literature review based on PubMed, AMIA conference proceedings and key references from publications identified. Search terms included practice guidelines, decision support, controlled vocabulary and medical record systems. Papers were reviewed by both authors and summarized narratively. RESULTS: There is a consensus that guideline delivery systems must be integrated with electronic health records (EHRs) to be most effective. Several evolving CIG formalisms have in common, use of a task network model. There is currently no dominant CIG system. The major challenge in development of interoperable CIGs, is agreement on a standard controlled vocabulary. Such standards are under development, but not widely used, particularly in commercial EHR systems. The Virtual Medical Record (VMR) concept has been proposed as a standard that would serve as an intermediary between guideline vocabulary and that used in EHR implementation. CONCLUSION: CIG systems are in a state of evolution. Standards efforts promise to improve interoperability without compromising innovation. The VMR concept can assist guideline development even before clinical systems routinely adhere to standards. Frontiers for future work include using the principles learned by computer implementation of guidelines to improve the guideline development process and evaluation methods that isolate the effects of specific CIG features.

Decision Making, Computer-Assisted↗
PubMed2000

Health economics of contraception.

Health economic analyses evaluate interventions from the standpoint of effectiveness and cost, important considerations in today's healthcare environment. Use of analytic cost-effectiveness approaches allows decision-makers to evaluate interventions in a more rational manner. With the use of sensitivity techniques, various scenarios can be evaluated, particularly as they relate to questions that have significant uncertainty. To date, there has been limited application of these methods to the area of contraception.

Adolescent↗
PubMed1999

The will to live among HIV-infected patients.

BACKGROUND: Patients infected with HIV value both longevity and health. OBJECTIVE: To understand how HIV-infected patients value their health. DESIGN: Interview study. SETTING: Regional treatment center for HIV. PATIENTS: 51 patients with HIV infection. MEASUREMENTS: Life-satisfaction, health rating, time-tradeoff, and standard-gamble scores. RESULTS: Of the 51 patients, 49% (95% CI, 35% to 63%) said that their life was better currently than it was before they contracted HIV infection; only 29% said that life was currently worse. The mean (+/- SD) time-tradeoff score was 0.95 +/- 0.10, indicating that, on average, patients would give up no more than 5% of their remaining life expectancy in their current state of health in exchange for a shorter but healthy life. The average health rating score was 71.0 +/- 18.7 on a scale of 0 to 100, and the average standard-gamble score was 0.80 +/- 0.27. Factors contributing to life satisfaction and time-tradeoff scores included spirituality and having children. CONCLUSION: Many patients with HIV have a strong will to live, and many feel that life with HIV is better than it was before they became infected.

Adult↗
PubMed1999

Is the societal perspective in cost-effectiveness analysis useful for decision makers?

BACKGROUND: The U.S. Public Health Service's Panel on Cost-Effectiveness in Health and Medicine recommends that cost-effectiveness analyses (CEAs) intended to help allocate health resources in the public interest include a reference case analysis, conducted from the perspective of society as a whole. This perspective requires that an analysis measure all health effects and changes in resource use caused by an intervention. VALUE OF SOCIETAL CEAs: Tensions unavoidably arise among the parties to medical decisions--patients, their families and friends, clinicians, and third-party payers. One common approach to handling these tensions is to ignore some of them, to "solve" them by pretending they do not or should not exist. Patients do this when they demand the best care for themselves without regard to the cost to others, payers when they make coverage decisions that shift costs ot others. But by estimating all gains and losses, calculations that reflect the safety, effectiveness, and side effects of an intervention as well as its costs, societal CEAs can help resolve those tensions and provide the basis for decisions that are fair to all parties, an agenda for negotiating such decisions, and information essential for designing compensation and incentives to support them. MAKING BETTER USE OF SOCIETAL CEAs: Use of the societal perspective asks that all parties be aware of and consider the interests of others. Some process or procedure needs to be developed for presenting CEA information to the parties most likely to be affected by decisions, soliciting their views, and negotiating an acceptable decision. This process could be used by government decision makers or by managed care organizations, professional societies, or payers.

Attitude to Health↗
PubMed1999

Risk of bacterial infection associated with allogeneic blood transfusion among patients undergoing hip fracture repair.

BACKGROUND: The relationship between allogeneic blood transfusion and bacterial infection remains uncertain. An increased risk of bacterial infection would represent the most important risk of allogeneic transfusion, because viral disease transmission has become so rare. STUDY DESIGN AND METHODS: A retrospective cohort study of 9598 consecutive hip fracture patients at least 60 years old who underwent surgical repair was performed. The primary outcome was serious bacterial infection, defined as bacteremia, pneumonia, deep wound infection, or septic arthritis or osteomyelitis. Secondary outcomes included two individual infections, pneumonia and urinary tract infection (UTI), and the cost of infection. Hospital cost of infection was assessed by linking the study population to Medicare data. RESULTS: Fifty-eight percent of patients received at least one transfusion. Serious bacterial infection occurred in 437 patients (4.6%); 28.8 percent of this group died during the hospital stay. Pneumonia occurred in 361 patients (3.8%) and UTI occurred in 1157 patients (12.1%). The adjusted risk of serious bacterial infection associated with transfusion was 1.35 (95% CI, 1.10-1.66). The adjusted risk for pneumonia was 1.52 (95% CI, 1.21-1.91), and that for UTI was 1.03 (95% CI, 0.91-1.17). A dose-response relationship was present for serious bacterial infection (p = 0.001) and pneumonia (p = 0.001). The cost of hospitalization was $14,000 greater for patients with serious infection than for patients without infection. CONCLUSION: Blood transfusion is associated with a 35-percent greater risk of serious bacterial infection and a 52-percent greater risk of pneumonia. Postoperative infections are costly. The risk of bacterial infection may be the most common life-threatening adverse effect of allogeneic blood transfusion.

Aged↗
PubMed1999

The cost-effectiveness of autologous transfusion revisited: implications of an increased risk of bacterial infection with allogeneic transfusion.

BACKGROUND: Previous analyses have found autologous transfusion to be very expensive but have not considered avoidance of postoperative bacterial infections as one of its benefits. STUDY DESIGN AND METHODS: A cost-utility analysis using a Markov cohort simulation model compared autologous blood transfusion to allogeneic transfusion in a hypothetical cohort of patients undergoing elective total hip replacement with respect to discounted quality-adjusted life years (QALYs) and health-care system costs. RESULTS: Assuming a base case rate of serious infection of 3.7 percent, a relative risk of infection of 1.85, and additional costs of $12,980 per infection, autologous transfusion has a cost-effectiveness of $2,470 per QALY. If the relative risk of bacterial infection following allogeneic transfusion exceeds 1.1, the cost-effectiveness of autologous transfusion is less than $50,000 per QALY and if the relative risk exceeds 2.4, autologous transfusion is dominant, resulting in both lower costs and greater QALYs. If there were no increased risk of transfusion, the cost-effectiveness of autologous transfusion would be $3,400,000 per QALY. CONCLUSIONS: If there is only a modest increase in the risk of bacterial infection following allogeneic transfusion, autologous transfusion would result in improved outcomes at a cost of less than $50,000 per QALY. Autologous transfusion would be dominant above a relative risk of infection that is within the range of values observed in randomized controlled trials. However, if there is no increased risk of bacterial infection, autologous transfusion would be a very expensive strategy. Until more definitive data are available on the magnitude and costs of this risk, we advise against prematurely closing the debate about the cost-effectiveness of autologous transfusion.

Adult↗
PubMed1994

Does physician performance explain interspecialty differences in malpractice claim rates?

Physician specialty has been consistently associated with different malpractice claim rates, with neurosurgery, orthopedics, and obstetrics and gynecology having the highest rates. Whether these differences reflect physician performance or other aspects of patient care that are unique for each specialty is unclear. A retrospective cohort study was performed including 12,829 physicians involved in 8,221 closed cases from 1977 to 1991. For each case an assessment was made whether the plaintiff received an award and whether the physician care of the patient was indefensible. An award was made to the plaintiff in 42% of cases. Physician care was considered indefensible in 23% of the cases. The specialties with the highest award rates were anesthesiology (58.3%), obstetrics and gynecology (47.5%), and radiology (43.0%). Neurosurgery had the lowest rate of award (30.2%). The specialties with the highest indefensibility rates were radiology (36%), obstetrics and gynecology (27%), and anesthesiology (27%). Neurosurgery had the lowest indefensibility rate (10%). These results were unchanged after controlling for physician age, degree, site of training, certification status, and severity of patient injury. In conclusion, differences in award rate and indefensibility are present, but not large enough to explain the large variation in specialty claim rates. This suggests that the variation in malpractice rates results from factors other than a meaningful difference in physician performance.

Clinical Competence↗
PubMed1994

Toward a peer review process for medical decision analysis models.

This paper presents a framework for a peer review process for medical decision analysis models. This framework is based on the collective experience of the members of the Inter-PORT Decision Modeling work group, a team of decision analysis experts comprising members from each of the Patient Outcomes Research Teams (PORTs), sponsored by the Agency for Health Care Policy and Research. Important general principles of correct model structure include choice of model type, perspective of the analysis, choice of utility scheme and identification of strategies that should be included and events that should be modeled. In addition, a set of rules for correct decision model structure may help to identify common errors. Although not necessarily exhaustive, this scheme provides an approach by which a reviewer may judge the adequacy of a decision model presented for publication or as the basis for a health policy.

Decision Support Techniques↗
PubMed1993

Who should be screened for HIV infection? A cost-effectiveness analysis.

BACKGROUND: The advent of effective prophylactic treatments for asymptomatic persons infected with human immunodeficiency virus has led to interest in widespread screening programs. However, the costs of screening programs and therapy are high, and the prevalence of infection above which screening becomes an appropriate use of scarce health care dollars remains undetermined. METHODS: To examine the cost-effectiveness of screening in populations with differing prevalences of infection, we developed a Markov model to compare costs and life expectancy for two strategies: (1) screening and prophylactic treatment for infected persons who have or who develop low CD4+ (T4) cell counts, and (2) no screening. Based on studies in the literature, we estimated the prevalence of HIV infection, the rate of T4-cell loss, the rates of developing the acquired immunodeficiency syndrome and Pneumocystis pneumonia stratified by T4 cell counts, the life expectancy with the acquired immunodeficiency syndrome, the efficacy of prophylactic therapies, and costs. RESULTS: In populations with a prevalence of infection more than 5%, which includes known risk groups, screening costs less than $11,000 per life-year gained. In populations with a prevalence as low as 0.15%, screening costs only $29,000 per life-year gained. Even when the efficacy of zidovudine is assumed to be limited to 3 years, screening still costs less than $40,000 per life-year gained in populations with a prevalence of 0.5% or greater. However, in populations with a very low prevalence of infection (two to 10/100,000), such as members of the general population without reported risk factors, screening costs rise to between $290,000 and $1,277,400 per life-year gained. CONCLUSIONS: When considering only direct medical benefits, screening for asymptomatic human immunodeficiency virus infection in the general population, without regard to reported risk factors or seroprevalence data, would be expensive. In populations with a prevalence of infection of 0.5% or greater, however, the cost-effectiveness of screening falls within the range of currently accepted medical practices. These results suggest that screening be offered routinely to all persons in defined populations, such as persons receiving care at hospitals or clinics, or residing in geographic areas, where the seroprevalence is 0.5% or more, and underscore the need to conduct seroprevalence studies to identify such populations.

AIDS Serodiagnosis↗
PubMed1993

Comparative cost-effectiveness analysis of theophylline and ipratropium bromide in chronic obstructive pulmonary disease. A three-center study.

The charts of 311 patients receiving theophylline (T) and 289 patients receiving ipratropium bromide (IB) for COPD were reviewed to determine the total costs and cost-effectiveness of these 2 agents in 3 different health-care settings. A direct cost-accounting method assessed cost, and a Markov decision-analysis model calculated cost-effectiveness. Costs to treat toxic effects were greater for T versus IB. The types and incidences of toxic effects, by drug, were similar among the three centers. Overall costs for T were $121.40 per patient per therapy-month versus $84.56 per patient per therapy-month for IB, as determined by the cost-accounting method. The marginal cost was $366 for T over IB when extrapolated over 1 year using the Markov model. The Markov model also predicted that patients receiving IB had a greater number of complication-free therapy-months (measurement of effectiveness) than patients receiving T. We conclude that treatment with IB was less costly and more cost-effective than T.

Aged↗
PubMed1992

The risks of blood transfusion: the relative influence of acquired immunodeficiency syndrome and non-A, non-B hepatitis.

PURPOSE: The acquired immunodeficiency syndrome epidemic has greatly increased concern about the risk of blood transfusion. Many transfusions are now autologous, and when these are not available, both physicians and patients are more likely to question the advisability of transfusion. We evaluate the risk of preoperative blood transfusion and the contribution of human immunodeficiency virus (HIV) infection to that risk. METHODS: We used decision analysis to characterize the risk associated with HIV infection in days of life lost. The contributions to risk of acute transfusion reaction, hepatitis B, and non-A, non-B hepatitis are also estimated. Sensitivity analyses show the implications for transfusion risk of recent information about HIV infection in the blood supply and a new test for hepatitis C. RESULTS: The analysis shows that the contribution of HIV infection to the risk of death from transfusion, expressed in days of life expectancy lost, has become extremely small over the last several years. Currently, HIV infection accounts for less than 1% of the risk of death, while non-A, non-B hepatitis accounts for 97% to 98%. Further reductions in the risk of HIV infection, even to zero, will make relatively little difference in the safety of transfusion. The analysis also shows that the remaining risk from transfusion should decrease sharply, by more than two thirds, with the adoption of the test for hepatitis C. CONCLUSIONS: Efforts to improve the safety of blood should focus on reducing the risk of non-A, non-B hepatitis. The remaining risk of HIV infection is very small.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Cost-effectiveness of the implantable cardioverter-defibrillator: effect of improved battery life and comparison with amiodarone therapy.

The implantable cardioverter-defibrillator (ICD) greatly reduces the incidence of sudden cardiac death among patients with recurrent sustained ventricular tachycardia and fibrillation who do not respond to conventional antiarrhythmic therapy. A cost-effectiveness analysis was performed, comparing the ICD, amiodarone and conventional agents. Actual variable costs of hospitalization and follow-up care were used for 21 ICD- and 43 amiodarone-treated patients. Life expectancy and total variable costs were predicted with use of a Markov decision analytic model. Clinical event rates and probabilities were based on published reports or expert opinion. Life expectancy with an ICD (6.1 years) was 50% greater than that associated with treatment with amiodarone (3.9 years) and 2.5 times that associated with conventional treatment (2.5 years). Assuming replacement every 24 months, ICD lifetime treatment costs (in 1989 dollars) for a 55-year old patient are expected to be $89,600 compared with $24,800 for amiodarone and $16,100 for conventional therapy, yielding a marginal cost/effectiveness ratio for ICD versus amiodarone therapy of 1f429,200/year of life saved, which is comparable to that of other accepted medical treatments. If technologic improvements extend average battery life to 36 months, the marginal cost/effectiveness ratio would be $21,800/year of life saved, and at 96 months it would be $13,800/year of life saved. Patient age at implantation did not significantly affect these results. If quality of life on amiodarone therapy is 30% lower than that with the ICD, the marginal cost/effectiveness ratio decreases by 35%. If the quality of life for patients receiving drugs is 40% lower than that of patients treated with an ICD, use of the defibrillator becomes the dominant strategy.

Amiodarone↗
PubMed1990

Myocardial revascularization for chronic stable angina. Analysis of the role of percutaneous transluminal coronary angioplasty based on data available in 1989.

No prospective, randomized clinical trial comparing coronary artery bypass grafting, percutaneous transluminal coronary angioplasty, and conservative therapy has been reported. To address when revascularization is indicated, we constructed a decision analytic model. Our model incorporates procedure-related mortality and morbidity, coronary artery disease-related mortality, and the benefit of revascularization. We determined the quality-adjusted life expectancy and expected costs for each strategy. Our model suggests that angioplasty is a reasonable alternative to bypass surgery in patients with favorable lesions if angioplasty would provide a comparable degree of revascularization. Our model predicts that patients treated with angioplasty will have more revascularization procedures than will patients treated with bypass surgery but predicts that both treatments will cost the same over the typical patient's lifetime. In many patients with severe angina or documented ischemia, angioplasty is indicated for stenosis of a single artery. In patients with two vessel disease that is amenable to angioplasty, angioplasty may be a reasonable alternative to bypass surgery. Even in patients whose three vessel disease can be completely revascularized by angioplasty, bypass surgery, although relatively expensive, is slightly better than angioplasty. In patients with three vessel disease and comorbidities that increase operative risk, angioplasty may be a reasonable alternative to either bypass surgery or medical therapy.

Angina Pectoris↗
PubMed1989

Bone marrow donor registries: the relation between registry size and probability of finding complete and partial matches.

In a registry of volunteer bone marrow donors, the relation between registry size and probability of finding an exact or partial match for a random recipient cannot be theoretically derived because it depends on specifics of the human leukocyte antigen (HLA) haplotype frequencies in the donor and recipient populations. The relation must be explicitly calculated using empirically determined HLA haplotype frequency data for all possible pairings between a donor and a recipient population. This report describes a general solution to this problem. The method shows that the relation of the probability of matching to registry size is sigmoidal, with small increases in probability at the extremes of registry size and a middle range of registry size within which the probability of matching increases most sharply. This range determines the approximate size of the most cost-effective registry. In addition, for any pairing of donor and recipient populations, there is a maximum probability of identifying a match of a given quality for a random recipient, which cannot be exceeded even if registry size were infinite. This upper limit is a function of the frequency of blank (or unknown) alleles in the donor and recipient populations; the higher that frequency, the lower the maximum probability of achieving any given quality of match. The determinants of the probability of achieving a given quality of match with a given registry size are (1) the genetic heterogeneity within the recipient and donor populations, which increases the registry size required to achieve a given probability of matching, and (2) the degree of genetic homology between the donor and recipient populations, which increases the maximum probability of matching and also lowers registry size requirements. The method described here can be used to estimate donor pool size requirements using any donor and recipient populations for which HLA frequency data are available.

Bone Marrow Transplantation↗
PubMed1988

Benign disappearance of ventricular thrombus after embolic stroke. A case report.

The source for a patient's middle cerebral artery territory embolic stroke was found by echocardiography to be a left ventricular cardiac thrombus. The apical mass was large, pedunculated, and moved with systole into the ventricular cavity. The absence of ventricular dyskinesia was thought to favor a tumor, and surgery was considered before repeat echocardiography showed disappearance of the mass, making thrombus the likely diagnosis. No further embolic events occurred during or since the disappearance of the thrombus while on anticoagulation therapy. Serial echocardiography for change in or disappearance of a ventricular mass may be critical in distinguishing thrombus from tumor.

Aged↗