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Biomedical subjects

S T Mennemeyer

Publications and source records attributed to S T Mennemeyer.

18 recordsLinked to original sources
PubMed2006

Randomized comparison of ultrasound surveillance and clinical monitoring on arteriovenous graft outcomes.

Arteriovenous graft thrombosis is a frequent event in hemodialysis patients, and usually occurs in grafts with significant underlying stenosis. Regular surveillance for graft stenosis, with pre-emptive angioplasty of significant lesions, may improve graft outcomes. This prospective, randomized, clinical trial allocated 126 hemodialysis patients with grafts to either clinical monitoring alone (control group) or to regular ultrasound surveillance for graft stenosis every 4 months in addition to clinical monitoring (ultrasound group). The two randomized groups were closely matched with respect to demographic, clinical, and graft characteristics, with the exception of a lower frequency of diabetes in the ultrasound group. The primary outcome was graft survival, and the secondary outcome was thrombosis-free graft survival. The frequency of pre-emptive graft angioplasty was 64% higher in the ultrasound group than in the control group (1.05 vs 0.64 events per patient-year, P<0.001), whereas the frequency of thrombosis was not different (0.67 vs 0.78 per patient-year, P=0.37). The median time to permanent graft failure was similar between the two groups (38 vs 37 months, P=0.93). Likewise, the median time to graft thrombosis or failure did not differ (22 vs 25 months, P=0.33). There was no significant association between diabetes and time to graft failure (P=0.93) or time to graft thrombosis or failure (P=0.88). In conclusion, the addition of regular ultrasound surveillance for graft stenosis to clinical monitoring increases the frequency of pre-emptive angioplasty, but may not decrease the likelihood of graft failure or thrombosis.

Aged↗
PubMed2001

Reducing the cost of diagnosis of breast carcinoma: impact of ultrasound and imaging-guided biopsies on a clinical breast practice.

BACKGROUND: The objective of this study was to determine whether the use of ultrasound and percutaneous breast biopsies in patients with screen-detected nonpalpable abnormalities can reduce benign open surgical biopsies of the breast without increasing cost or sacrificing detection of potentially curable breast carcinomas. METHOD: Using a computerized mammography database and consecutive logs of needle localization procedures and fine- and large core needle biopsies of a single university-based breast imaging practice, the authors determined the breast carcinoma yield and cost of diagnosis over a 14-year period and the changes that occurred over time with the sequential introduction of ultrasound, ultrasound-guided biopsies, and stereotactic biopsies. RESULTS: The overall breast carcinoma yield for needle localization biopsies of nonpalpable lesions increased from 21% in 1984 to 68% in 1998 (P < 0.0001). The yield for nonpalpable masses increased from 21% to 87% (P < 0.0001) over the same period. The selective use of ultrasound alone and percutaneous fine- and large core needle biopsy resulted in a substantial reduction in benign open surgical biopsies. A cost analysis showed a 50% reduction in the average expense of discovering breast carcinoma. The breast carcinomas detected after introduction of these methods were prognostically favorable with 88% measuring 1.5 cm or less in size and 66% measuring less than 1 cm. CONCLUSIONS: Selective use of ultrasound and imaging-guided percutaneous biopsies can significantly reduce the number of benign open surgical biopsies generated by mammographic screening. This can result in substantial cost savings without decreasing the sensitivity for detecting small potentially curable lesions.

Biopsy, Needle↗
PubMed1997

A bootstrap approach to medical decision analysis.

In economic evaluations of health treatments, the sensitivity of a cost-benefit (CB), cost-effectiveness (CE) or cost-utility (CU) analysis to changes in modeling assumptions, variation in data, and sampling error is important. The typical approach to this problem is ad hoc experimentation; namely, a few parameters of particular interest are changed, either separately or in combination, over plausible ranges. The impact of random variation in the data is seldom explored beyond parametric tests of the statistical significance of estimated coefficients. This note suggests a systematic approach to sensitivity analysis. Bootstrap sampling is used to determine to what extent the patients' response to treatment and economic consequences might vary due to many replications of a clinical trial.

Clinical Medicine↗
PubMed1997

Antiviral therapy for neonatal herpes simplex virus: a cost-effectiveness analysis.

Each year, about 1,600 infants in the United States are infected with neonatal herpes simplex virus. We conducted a cost-effectiveness analysis of antiviral drug therapy (acyclovir) for three forms of herpes simplex virus infection: skin, ear, and mouth (SEM), central nervous system (CNS), and disseminated multiorgan (DIS) disease. Five levels of patient outcomes were examined (normal, mild, moderate, severe, dead). We obtained information on disease occurrence and survival from clinical trials and historical reviews of untreated newborns. We considered approaches for treating all or any of the forms of the disease and compared them with no use of antiviral drugs. The main measure of effectiveness was lives saved, including those of descendants of survivors. Costs were measured from a societal perspective and included direct medical costs, institutional care, and special education. We used a discount rate of 3% and valued dollars at 1995 levels. We also considered the perspective of a managed care organization. From a societal viewpoint relative to no treatment, antiviral therapy for SEM resulted in a gain of 0.8 lives and a cost reduction of $78,601 per case. For the treatment of CNS and DIS disease, antiviral therapy saved more lives but at increased cost, with respective marginal costs per additional life saved of $75,125 and $46,619. From a managed care perspective, antiviral therapy is more cost-effective than from a societal viewpoint because costs of institutional care and special education are not the responsibility of managed care organizations. Development of at-home therapies will further improve the cost-effectiveness of antiviral therapy for neonatal herpes simplex virus infection.

Acyclovir↗
PubMed1997

Death and reputation: how consumers acted upon HCFA mortality information.

From 1986 through 1992, the Health Care Financing Administration (HCFA) released information comparing patient death rates at individual hospitals. This was viewed widely as an effort to aid consumers in selecting hospitals. This study evaluates how the release of this information affected hospital utilization, as measured by discharges. It finds a very small, but statistically significant effect of the HCFA data release. A hospital with an actual death rate twice that expected by HCFA had fewer than one less discharge per week in the first year. However, press reports of single, unexpected deaths were associated with an average 9% reduction in hospital discharges within one year. HCFA was justified in eliminating its mortality report, not because it was being used by consumers to choose hospitals, but because it was not. Implications for report cards are discussed.

Attitude to Health↗
PubMed1996

Screening for clinical laboratory errors with Medicare claims data: results for digoxin.

A statistical model is demonstrated for finding outpatient clinical laboratories having high frequencies of bad patient outcomes, after testing, that may indicate testing errors. A sample of Medicare Part A and Part B claims for 30,685 digoxin tests for 1985 through 1987 was analyzed. Deaths or digoxin-related hospitalizations within 14 days of digoxin testing are defined as "adverse events" potentially influenced by test information. Approximately 3.3% of digoxin tests were followed by adverse events with two-thirds resulting in hospitalization or death. Adverse events were (a) lower in states with stronger laboratory regulations, (b) 15% higher whenever the site of testing switched, (c) unrelated to testing in low volume physician office laboratories, and (d) unrelated to frequency of digoxin testing in previous 6 months. Results a and b are consistent with findings for prothrombin testing but c and d are not. Differences are consistent with technical characteristics of the tests.

Anti-Arrhythmia Agents↗
PubMed1994

Strategies for the prevention of early-onset neonatal group B streptococcal sepsis: a decision analysis.

OBJECTIVE: To perform a decision analysis to understand better the implications of 19 potential group B streptococcus screening and treatment strategies. METHODS: We searched the literature to locate appropriate articles from which to derive probability estimates. Using decision analysis, we determined the likely outcomes of 19 group B streptococcus screening and treatment strategies and focused on three main outcomes: 1) number of expected cases of early-onset neonatal group B streptococcal sepsis, 2) percentage of gravidas treated with intrapartum antibiotics, and 3) total costs. RESULTS: The strategy recently recommended by two committees of the American Academy of Pediatrics (universal 28-week maternal rectovaginal group B streptococcal culture and treatment of culture-positive, high-risk patients in labor) is among the least effective at reducing neonatal sepsis and the most costly. Strategies based on the currently available rapid streptococcus identification tests are ineffective at reducing neonatal sepsis and are costly. Three strategies outperform the rest: 1) Universal intrapartum maternal antibiotic treatment is the most effective strategy in reducing early-onset neonatal group B streptococcal sepsis (6% of expected) and is also the least costly; 2) intrapartum treatment based solely on risk factors (recently endorsed by ACOG) lowers the rate of neonatal sepsis to 31% of expected with an 18% maternal treatment rate and low total costs; and 3) universal 36-week maternal culture, and treatment of all patients experiencing preterm birth and all culture-positive patients results in 14% of expected neonatal sepsis, with a 27% maternal treatment rate and low total costs. CONCLUSION: Given the present state of knowledge, three strategies emerge from this decision analysis as most optimal for the prevention of early-onset neonatal group B streptococcal sepsis: universal treatment, treatment based on risk factors, and treatment based on preterm delivery and 36-week culture status.

Anti-Bacterial Agents↗
PubMed1994

Bed rest in pregnancy.

OBJECTIVE: To summarize existing data about the effectiveness of bed rest when used to improve various pregnancy outcomes and to determine how often bed rest is used and the cost associated with its use. DATA SOURCES: We used the MEDLINE data base to search for all English language papers evaluating the effectiveness of bed rest in pregnancy. We also reviewed a number of textbooks and the 1988 National Infant Mortality Survey. METHODS OF STUDY SELECTION: We reviewed these sources for recommendations about using bed rest in various obstetric conditions. We used the 1988 National Infant Mortality Survey to determine how often bed rest was used either to prevent or to treat various obstetric conditions and estimated the costs associated with its use. DATA EXTRACTION AND SYNTHESIS: Bed rest is used in nearly 20% of all pregnancies to prevent or treat a wide variety of conditions, including spontaneous abortion, preterm labor, fetal growth retardation, edema, chronic hypertension, and preeclampsia. There is little evidence of effectiveness. The estimated costs associated with bed rest, including hospitalization, lost wages, and lost domestic productivity, range from more than $250 million to billions of dollars per year. CONCLUSIONS: Bed rest is used extensively to treat a wide variety of pregnancy conditions, at substantial cost but with little proof of effectiveness. We recommend that because this intervention has failed the test of effectiveness, its use during pregnancy should be curtailed unless randomized trials demonstrate improvement in a specific outcome.

Bed Rest↗
PubMed1993

Searching for inaccuracy in clinical laboratory testing using Medicare data. Evidence for prothrombin time.

OBJECTIVE: To determine if the occurrence of health outcomes following clinical laboratory testing can be used to identify types of laboratories that may be having higher than expected error rates. DESIGN: Retrospective analysis of Medicare Part B outpatient claims, Part A hospitalization bills, and death records using a case-control study. SETTING: Medicare records from six carrier territories were sampled during the period 1985 through 1987. PATIENTS: A total of 14,755 Medicare patients receiving a prothrombin time test in either a physician office laboratory or a commercial laboratory. OUTCOME MEASURES: Occurrence of a hospitalization for stroke or acute myocardial infarction, death, or no adverse outcome within 6 days of a prothrombin time. RESULTS: In physician office laboratories where prothrombin time test volume is below 40 per month, the odds that a tested patient will experience a stroke or an acute myocardial infarction are up to 1.96 and 3.43 times greater, respectively, than for a similar patient tested in a commercial laboratory. Switching from one laboratory to another between successive prothrombin time tests increased the odds of a stroke or an acute myocardial infarction by 1.57 and 1.32, respectively. Patients in two states with strong laboratory regulatory programs had fewer adverse outcomes. CONCLUSION: Examining patient outcomes subsequent to clinical laboratory testing may be a useful tool for clinical laboratory quality assurance.

Case-Control Studies↗
PubMed1991

Downstream outcomes: using insurance claims data to screen for errors in clinical laboratory testing.

A methodology is described by which health insurance claims data might be used to discover the occurrence of systematic errors by clinical laboratories. False-positive results should generate a series of tests or treatments that are eventually abandoned as the false signal of the initial test is discovered while false-negative results may cause necessary tests or treatments to be unduly delayed. False results may also generate adverse outcomes such as an unusually high number of deaths or hospitalizations among persons who have received particular laboratory tests. Health insurance claims data may be used to discover these patterns and how the inclusion of laboratory results on claims would improve the precision of such inferences. Appropriate statistical tests are discussed.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed1989

Selective contracting in California: its effect on hospital finances.

In 1983, the State of California used a modified form of competitive bidding to select hospitals that would supply inpatient care for the Medi-Cal (Medicaid) program. Selective contracting halted a long history of hospital price inflation and won significant price concessions for the state. While the state might have used the bidding program to get the cheapest possible care from the worst possible providers, the evidence shows that it was used to secure price concessions from mainstream hospitals that provided accessible, good-quality care. Various administrative tools of admissions review were important adjuncts to both utilization control and quality assurance.

Accounts Payable and Receivable↗
PubMed1984

Effects of competition on Medicare administrative costs.

This paper examines the effects of introducing competitive contracting into the Medicare: Part B program. The administrative costs of contractors (carriers) who process Medicare claims for medical services are examined to determine relative efficiencies of firms operating under either competitive or non-competitive contracts. Pooled time-series cross-sectional data are used to estimate an average total cost function. Findings are that (1) appreciable cost reductions were obtained by the introduction of competition, (2) economies of scale are present in Medicare claims processing, and (3) carriers who are non-profit organizations (i.e. Blue Shield plans) do not exhibit higher costs than comparable commercial insurance companies.

Contract Services↗
PubMed1978

Really great returns to medical education?

This article reports the value of a medical education as opposed to education for alternative professional careers, using 1970 Census data. When standard net present value computations are performed, it is found that the returns to investment in medical education exceed those to education for alternative professions. When the computations are adjusted for hours worked, physicians' earnings become roughly equal to those of dentists and lawyers but remain clearly superior to those of the other professions considered. Additional information on the earnings of physician cohorts vs. dentist cohorts for the post-Flexner era is also reported.

Adult↗
PubMedDate not supplied

Using patient outcomes to screen for clinical laboratory errors.

How to measure the quality of laboratory testing has long been a challenging problem for laboratory managers and accrediting agencies. Traditionally, laboratory quality has been assessed by direct inspection, proficiency testing, and the credentials of staff. None of these methods is entirely satisfactory at answering a fundamental question: does the laboratory give technically accurate and clinically meaningful information for each patient that it tests? This paper discusses how information on patient outcomes can be used to screen for laboratories that may be making frequent random or systematic errors. This approach is called downstream event monitoring (DEM). The basic idea is to look at what happens to a laboratory's patients in a critical window of time after they have been tested. The approach carries out a basic adage of quality management: follow up with your customers to see if your product has met their needs. The main idea of DEM is that if a laboratory has not conveyed accurate information, the clinician may take actions that fail to help, or maybe even harm, the patient. If a laboratory's patients have an unusually high rate of adverse events that happen within a window of time when the laboratory test would have played a critical role, the laboratory should be further examined to see if it is the cause of the problem. Right now, DEM is a technique under development. It needs a clinical logic to relate a patient's outcomes back to a laboratory test, and it needs good data to compare laboratories. This paper discusses how the prothrombin time test and the serum digoxin test have been examined for Medicare patients to see if certain laboratory characteristics are associated with unusually high occurrences of adverse events after testing. The need for future validation studies is also discussed.

Clinical Laboratory Techniques↗