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H Krakauer

Publications and source records attributed to H Krakauer.

At least 19 recordsLinked to original sources
PubMed1999

A method for correcting for the variability of inhibitory effects of soluble human interleukin 1 receptor II measured by different ELISAS.

Seven ELISAs were developed by using several combinations of anti-human IL-1beta antibodies for detecting interleukin 1beta (IL-1beta) in cell culture supernatants. These ELISAs have different sensitivities in detecting standard preparations of recombinant human IL-1beta (WHO reference standard) compared with conventional preparations of IL-1beta produced by stimulated human peripheral blood mononuclear cells. The observed differences were attributed to differences in epitope specificity of the various monoclonal antibodies used and the heterogeneity of IL-1beta secreted into culture supernatants. The presence of soluble IL-1 receptor type I did not alter the levels of IL-1beta detected by these ELISAs. However, soluble IL-1 receptor type II interfered with the detection of IL-1beta to different degrees in these ELISAs. A method involving standarization by means of separate measurement of the amount of receptor and its inhibitory effect in the IL-1beta ELISA, yields consistent estimates of the correct IL-1beta levels.

Artifacts↗
PubMed1998

'Best clinical practice': assessment of processes of care and of outcomes in the US Military Health Services System.

The National Quality Management Program of the Military Health Services System of the United States has undertaken a series of projects whose objective is the active, on-going monitoring and improvement of the effectiveness and efficiency of the care provided to a broad population that encompasses troops on active duty, retirees and dependents. The analytic activities consist of (1) identification by clinical panels of conditions and procedures of interest; (2) collection of data from electronic repositories and from charts to characterize the patients, how they are managed, the clinical outcomes they experience, the resource costs their care entails, and, from questionnaires, their functional status and level of satisfaction, and (3) generation of 'report cards' that inform organizational units down to the level of the hospital of the characteristics of their patients, their practices, and the risk-adjusted outcomes they achieve. The patterns of care employed by the hospitals that obtain the best risk-adjusted outcomes and resource utilization ('best clinical practice') are identified and made known. In addition, (4) a systematic process of developing outcomes-based practice guidelines has been devised. It intent is to serve as a decision-support tool for clinicians. Initial estimates have been obtained of the probable consequences of the application of this tool to operative interventions in childbirth. Use of the tool would result in a higher occurrence of elective Caesarean sections, a reduced rate of emergency Caesarean sections and much lower use of forceps, with an overall improvement in outcomes and lower resource costs. This program is currently in the early phases of implementation. The two principal requirements for the immediate future are (1) education of the clinical and administrative communities in the use of the data and the decision-support tools and (2) evaluation of the consequences of the use of the data by the clinical and administrative communities.

Benchmarking↗
PubMed1998

Validity of the Department of Defense Standard Inpatient Data Record for quality management and health services research.

OBJECTIVE: To assess the validity of the Department of Defense's Standard Inpatient Data Record (SIDR) for health services research and quality measurement. SUBJECTS: Patients whose inpatient charts were abstracted through the Civilian External Peer Review Program's studies of acute myocardial infarction (N = 1,432) and 1993 review of the birth product line (N = 9,705). METHODS: Separate databases of professionally abstracted (the clinical data set) and hospital-reported (the administrative SIDR data set) diagnoses and procedures were compared for each patient, and the sensitivity and specificity of the SIDR for elements in the Civilian External Peer Review Program's clinical "gold standard" data set were calculated. Agreement beyond chance was examined with kappa statistics. RESULTS: The clinical data set's principal procedure was found as a SIDR principal or secondary procedure in 92.5% of cases. Sensitivities of the SIDR data for common diagnoses in the clinical data ranged from 64% (viral infection) to 97% (diabetes), with kappa statistics ranging from 0.55 to 0.96. Procedural sensitivities ranged from 77% (echocardiography) to 99% (cesarean section), with kappa statistics ranging from 0.7 to 1.0. CONCLUSIONS: Our analyses indicate that the Department of Defense's SIDR is a reliable source of administrative data that compares favorably with traditional civilian quality management and health services research data sources, such as those from the Health Care Financing Administration and large insurers.

Female↗
PubMed1997

The relationship of the value of outcome comparisons to the number of patients per provider.

PURPOSE: Monte Carlo methods were used to assess how the value of outcome comparisons depends on the number of patients per provider. METHODS: We simulated two patient data sets that have been used for well-known studies of outcome comparisons: mortality rates for coronary artery bypass surgeons from New York and Pennsylvania, and 30-day hospital mortality rates of Medicare patient from a national data set. In the simulated data sets, each surgeon or hospital provider was assigned a true or underlying probability of mortality. RESULTS: For the simulated CABG surgery data set, the underlying probability of mortality explained 30% of the variation in the observed mortality rate when there were 100 patients per physician, and 63% when there were 400 patients. The positive predictive value of using an observed mortality rate in the bottom 10% to identify a surgeon whose underlying probability of mortality was in the bottom 10% was 31% for 100 patients and 59% for 400 patients. The relationship between underlying and observed rates was weaker in the simulated Medicare data set with the same number of patients per provider. For a given data set, the amount of random variation in the observed rates of adverse outcomes among providers can be estimated with a simple equation. CONCLUSION: The results show that the assessment of provider outcomes may be greatly affected by random variation. An indication of the amount of random variation in a given data set can be obtained from the examples in this study and an equation for estimating random variation.

Computer Simulation↗
PubMed1997

Competency in health care management: a training model in epidemiologic methods for assessing and improving the quality of clinical practice through evidence-based decision making.

This article describes a training model that focuses on health care management by applying epidemiologic methods to assess and improve the quality of clinical practice. The model's uniqueness is its focus on integrating clinical evidence-based decision making with fundamental principles of resource management to achieve attainable, cost-effective, high-quality health outcomes. The target students are current and prospective clinical and administrative executives who must optimize decision making at the clinical and managerial levels of health care organizations.

Clinical Competence↗
PubMed1996

Gastroenterology workforce modeling.

OBJECTIVE: To examine the current supply and distribution of gastroenterologists and project future supply under various scenarios to provide a paradigm for workforce reform. DESIGN: An analysis of current practices and distribution of gastroenterologists and a demographic model, using the 1992 gastroenterology workforce as a baseline. MAIN OUTCOME MEASURE: Comparison of current supply, distribution, and practice profiles with past data and future projections, using analyses of data from the 1993 Area Resource File, 1992 Medicare Part B file, age- and sex-specific death and retirement rates from the Bureau of Health Professions, managed care staffing patterns, the National Survey of Internal Medicine Manpower, and the Bureau of the Census. RESULTS: Rapid growth in the number of US gastroenterologists has resulted in a gastroenterologist-to-population ratio double that used on average by health maintenance organizations. In addition, the work profile of gastroenterologists is shared significantly by primary care physicians and other specialists, with the exception of a few specific and uncommon procedures. CONCLUSIONS: Empirical evidence suggests that, even in the absence of detailed models to describe the desired supply/need balance for gastroenterology, the US health care system and clinicians may benefit from a reduction in gastroenterology training programs. The Gastroenterology Leadership Council endorsed a goal of 25% to 50% reduction in trainee numbers over 5 years, and recent National Resident Matching Program data indicate that a voluntary downsizing process is in full force. This study illustrates a paradigm for workforce planning that could be useful for other medical specialties.

Demography↗
PubMed1996

Physician impact on hospital admission and on mortality rates in the Medicare population.

OBJECTIVE: We assess the effect of variations in the supply and specialty distribution of physicians on admission rates for ambulatory care-sensitive conditions (ACS) and for all causes, and on mortality rates among Medicare beneficiaries of various health care service areas (HCSA). DATA SOURCES: For the Medicare beneficiaries, sources were the Health Care Financing Administration's 1992 enrollment and impatient (Part A) files for a 5 percent sample of that population; for the overall populations and for the medical resources of the HCSAs, the Area Resource File. STUDY DESIGN: This observational, cross-sectional study employed multiple linear regression to assess the influence of population characteristics and of the supply of physicians on hospital admissions, and Poisson regression in the analysis of the factors that affect mortality. PRINCIPAL FINDINGS: Physician supply levels vary nearly fourfold or more when comparing the top and bottom deciles of the HCSAs, Medicare admissions for ACS conditions vary about threefold, and admission rates for all causes and mortality rates vary about 1.5-fold. Physician supply levels and distributions have very little influence on ACS admission rates, and even less on the admissions for all causes and on mortality, except in HCSAs with very low physician supply levels (one-fourth the national average or less). However, these HCSAs account for only about 1 percent of the U.S. population. CONCLUSIONS: Physician supply levels and the proportions of specialists and generalists have negligible effects on health status as measured by mortality rates and by rates of admission for all causes and for conditions presumed to be sensitive to the adequacy of ambulatory care. Reductions in admissions for such conditions are not likely to be achieved through broadening of insurance to levels that exist under Medicare, nor through increases in the supply of physicians, nor, conversely, through a reduction in any presumed oversupply of physicians.

Aged↗
PubMed1995

The relationship of clinical outcomes to status as a Medicare-approved heart transplant center.

This study reports the evaluation of the validity and utility of the Medicare heart transplant center selection process, as outlined in its 1986 Heart Coverage Regulations. A total of 9401 heart transplants performed in the U.S. between 1986 and 1991 were analyzed. The outcomes assessed were mortality and the occurrence of infection during the hospital stay. Outcomes experienced by centers with and without Medicare approval were compared directly and following adjustment for patient risk factors. Patients at centers that satisfied the Medicare criteria experienced lower mortality. The risk-adjusted hazard ratio for death over the five years of observation was 0.874 (P = 0.005). The probability of death following a transplant at a Medicare-approved center was 7.0 +/- 0.4% at 30 days and 16.2 +/- 0.6% at one year, and 9.2 +/- 0.4% and 19.2 +/- 0.6%, respectively, at centers without Medicare approval (P = 0.001). The difference appeared to be principally associated with death within 30 days of admission due to nonspecific graft failure. The posttransplant infection rate at Medicare-approved centers was 0.743 (P < 0.001) but this result is strongly confounded with differences in reporting patterns of the two types of centers. Criteria used by HCFA identify medical centers where outcomes of heart transplantation, as measured by mortality, are superior. This difference is established early, persists over time, and is not attributable to the numerous risk factors considered in our models. Overall, the results of the present study suggest that "centers of excellence" can be identified through the evaluation of center characteristics and outcomes, and that this approach chosen by HCFA may have broad health care systems applications.

Adolescent↗
PubMed1995

Serum levels of tumor necrosis factor-alpha, interleukin-1, and interleukin-6 in hemorrhagic fever with renal syndrome.

Hemorrhagic fever with renal syndrome is an acute viral disease caused by hantavirus. On the basis of clinical observation, the illness is divided into five sequential stages: febrile, hypotensive, oliguric, diuretic, and convalescent. Because interleukin-1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) are mediators responsible for fever, septic shock, and acute phase protein induction, we examined, using ELISA, the presence of these three cytokines in 276 sera collected during the Korean Conflict from 110 patients. Detectable levels (> 20 pg/ml) of TNF-alpha, IL-1 beta, and IL-6 occurred in 14, 14, and 33% of these samples, respectively. There was a significant correlation between serum levels of IL-1 beta and TNF-alpha (r = 0.66, p < 0.001), IL-1 beta and IL-6 (r = 0.59, p < 0.001), and IL-6 and TNF-alpha (r = 0.71, p < 0.001). The pathophysiologic processes of HFRS do not have clear or consistent correlations with alterations in the levels of the cytokines studied.

Disease Progression↗
PubMed1994

The impact of HLA mismatches on the survival of first cadaveric kidney transplants.

BACKGROUND: The benefits of HLA-A, B, and DR matching of cadaveric kidney grafts and recipients remain controversial when viewed from the perspective of social equity and graft survival. METHODS: We estimated graft survival using proportional-hazards techniques, adjusting for patient and donor characteristics, for a series of 30,564 Medicare patients receiving a first cadaveric kidney transplant between 1984 and 1990. The effects of minimal achievable HLA mismatches and maximal matching on graft survival were estimated by simulated allocation of a sample of organs to a sample of 20,000 candidates for transplantation. RESULTS: The adjusted one-year graft survival was 84.3 percent for grafts with no mismatches and 77.0 percent for grafts with four mismatches. National rationing of donor organs to achieve minimal mismatching and maximal matching could potentially decrease the average number of HLA mismatches from 3.6 to 1.2, with a corresponding increase in the number of matches. As a consequence, projected five-year graft survival could potentially increase from 58.5 percent to 62.9 percent. This would be associated with a decrease in the proportion of kidneys allocated to black recipients from 22.2 to 15.0 percent. CONCLUSIONS: Under ideal circumstances, a policy of maximal matching of cadaveric renal transplants would increase five-year graft survival by a comparatively small 4.4 percentage points, but the actual benefit is likely to be smaller.

Adolescent↗