Barbara McNeil - Profile on Academia.edu (original) (raw)
Papers by Barbara McNeil
Catheterization and mortality in elderly patients with acute myocardial infarction
JAMA: The Journal of the American Medical Association, 1995
Critical Questions Regarding a New Diagnostic Technology: A Case Study Using Computerized Tomography of the Head
The patient's role in assessing the value of diagnostic tests
Radiology, 1979
Diagnostic tests are usually evaluated for their informational content and effect on health outco... more Diagnostic tests are usually evaluated for their informational content and effect on health outcomes. Yet patient attitudes toward taking risks and the morbid sequelae associated with either the diagnostic test or its consequences are seldom considered. The authors present a prototypical model which incorporates patient attitudes into the evaluative process. Based on traditional indices of test efficacy, preoperative searches for occult metastases in patients with presumably operable bronchogenic carcinoma should never be performed. However, if patient attitudes toward perioperative death are considered, many should have preoperative staging tests. The exact percentage of patients benefiting from testing varies with test sensitivity and specificity. This integrative approach is appropriate for oncologic patients who frequently undergo treatment.
A prospective study of computed tomography and ultrasound in the detection and staging of pelvic masses
Radiology, 1983
Findings from computed tomography (CT) and ultrasound (US) examinations of 74 patients who were c... more Findings from computed tomography (CT) and ultrasound (US) examinations of 74 patients who were clinically thought to have pelvic masses and of 110 patients who had possible recurrence of pelvic tumors were analyzed. There was no significant difference in the ability of the two modalities to identify masses or to predict disease extent. Although both CT and US failed to detect some examples of spread outside of the pelvis, overstaging (apart from two cases of unconfirmed parametrial spread) did not occur with CT and occurred only once with US. The sensitivity was 0.96 for CT and 0.91 for US in the detection of pelvic masses. Both modalities had an accuracy of 0.81 in the detection of recurrent disease.
Preoperative and follow-up bone scans in patients with primary carcinoma of the breast
Surgery, gynecology & obstetrics, 1978
We have attempted to evaluate the role of preoperative and postoperative bone scans in patients w... more We have attempted to evaluate the role of preoperative and postoperative bone scans in patients with localized carcinoma of the breast. The yield of positive preoperative scans in patients with Stages I and II disease is low and confounded by a relatively high percentage of false-positive results. Conversely, 16 per cent of patients with Stage III disease had evidence of bony metastasis at the time of operation. Positive bone scans were found three times as frequently in patients with axillary node involvement than in those without. Thirty per cent of those observed for varying times up to 41 months had evidence of bony metastases. Again, there was a correlation with initial clinical staging with 3.6 to 8.0 times more conversions in patients with Stage II or III disease than in those with Stage I disease. It appears that the majority of metastases to the bone become apparent within the first years. This observation deserves further study to elaborate the natural history of metastati...
Comparing a medical records-based and a claims-based index for measuring comorbidity in patients with lung or colon cancer
Journal of Geriatric Oncology, 2015
Ascertaining comorbid conditions in cancer patients is important for research and clinical qualit... more Ascertaining comorbid conditions in cancer patients is important for research and clinical quality measurement, and is particularly important for understanding care and outcomes for older patients and those with multi-morbidity. We compared the medical records-based ACE-27 index and the claims-based Charlson index in predicting receipt of therapy and survival for lung and colon cancer patients. We calculated the Charlson index using administrative data and the ACE-27 score using medical records for Veterans Affairs patients diagnosed with stage I/II non-small cell lung or stage III colon cancer from January 2003 to December 2004. We compared the proportion of patients identified by each index as having any comorbidity. We used multivariable logistic regression to ascertain the predictive power of each index regarding delivery of guideline-recommended therapies and two-year survival, comparing the c-statistic and the Akaike information criterion (AIC). Overall, 97.2% of lung and 90.9% of colon cancer patients had any comorbidity according to the ACE-27 index, versus 59.5% and 49.7%, respectively, according to the Charlson. Multivariable models including the ACE-27 index outperformed Charlson-based models when assessing receipt of guideline-recommended therapies, with higher c-statistics and lower AICs. Neither index was clearly superior in prediction of two-year survival. The ACE-27 index measured using medical records captured more comorbidity and outperformed the Charlson index measured using administrative data for predicting receipt of guideline-recommended therapies, demonstrating the potential value of more detailed comorbidity data. However, the two indices had relatively similar performance when predicting survival.
Hospital Response to DRG-Based Prospective Payment
Medical Decision Making, 1985
The introduction of the Medicare Prospective Payment System (PPS) is markedly influencing the env... more The introduction of the Medicare Prospective Payment System (PPS) is markedly influencing the environment in which hospitals care for patients, teach medical students and residents, and perform clinical research. Hospitals, particularly teaching institutions, are responding to this challenge by developing new management reports, by analyzing physicians' practice patterns, and by estimating more precisely the fixed and variable costs of various ancillary services. The common objective of these activities is to improve our knowledge of clinical practices, and thereby improve decisions relating to the cost-effectiveness and quality of care delivered to patients in the hospital.
Trends in the use of drag therapies in patients with acute myocardial infarction: 1988 to 1992
Journal of the American College of Cardiology, 1994
Results. The overall thrombolysis rate for patients with acute myocardial infarction increased fr... more Results. The overall thrombolysis rate for patients with acute myocardial infarction increased from 11% in fiscal year 1988 to 18% in fiscal year 1990 and has remained approximately at that level since then. In mid-1989, tissue plasminogen activator was used in 90% of the ...
Brigham and Women's Hospital Handbook of Diagnostic Imaging
Radiology
Basically there are 62 sections on some of the most common dilemmas dealt with. These are followe... more Basically there are 62 sections on some of the most common dilemmas dealt with. These are followed by four interesting appendixes. The clinical sections are grouped under eight headings: abdominal disease (12 sections), genito-urinary disease (seven), chest ...
Radiology, 2017
In both the United States and Europe, efforts to reduce soaring health care costs have led to int... more In both the United States and Europe, efforts to reduce soaring health care costs have led to intense scrutiny of both standard and innovative uses of imaging. Given that the United States spends a larger share of its gross domestic product on health care than any other nation and also has the most varied health care financing and delivery systems in the world, it has become an especially fertile environment for developing and testing approaches to controlling health care costs and value. This report focuses on recent reforms that have had a dampening effect on imaging use in the United States and provides a glimpse of obstacles that imaging practices may soon face or are already facing in other countries. On the basis of material presented at the 2015 meeting of the International Society for Strategic Studies in Radiology, this report outlines the effects of reforms aimed at (a) controlling imaging use, (b) controlling payer expense through changes in benefit design, and (c) contro...
Probabilistic sensitivity analysis using Monte Carlo simulation
The data for medical decision analyses are often unreliable. Traditional sensitivity analysis--va... more The data for medical decision analyses are often unreliable. Traditional sensitivity analysis--varying one or more probability or utility estimates from baseline values to see if the optimal strategy changes--is cumbersome if more than two values are allowed to vary concurrently. This paper describes a practical method for probabilistic sensitivity analysis, in which uncertainties in all values are considered simultaneously. The uncertainty in each probability and utility is assumed to possess a probability distribution. For ease of application we have used a parametric model that permits each distribution to be specified by two values: the baseline estimate and a bound (upper or lower) of the 95 percent confidence interval. Following multiple simulations of the decision tree in which each probability and utility is randomly assigned a value within its distribution, the following results are recorded: (a) the mean and standard deviation of the expected utility of each strategy; (b) the frequency with which each strategy is optimal; (c) the frequency with which each strategy "buys" or "costs" a specified amount of utility relative to the remaining strategies. As illustrated by an application to a previously published decision analysis, this technique is easy to use and can be a valuable addition to the armamentarium of the decision analyst.
Ordering Tests in the United States and England-Reply
Jama, Apr 5, 1985
Biochemistry Usa, 1973
Numerical methods have been developed for rapid simultaneous determination of sedimentation and d... more Numerical methods have been developed for rapid simultaneous determination of sedimentation and diffusion coefficients from transient state sedimentation analyses based on computer simulated data. Application of this methodology to experimental data obtained for ribonuclease A and chymotrypsinogen A demonstrates that the values of the sedimenta-S edimentation in the ultracentrifuge occurs in a sectorshaped cell in a nonuniform force field; resulting concentration changes as functions of time and space are described by the mass conservation equation (Lamm, 1929) Few explicit experimental attempts have utilized the dynamic aspects of this formulation in their totality although measurements of concentration changes with time throughout the liquid column have been used in the determination of the sedimentation coefficient of thallous sulfate (Creeth, 1962), and evaluation of such changes at the air-liquid meniscus has led to the development of several different approaches to determination of molecular weights of macromolecules (LaBar, 1965 ; Charlwood, 1967; Simpson and Bethune, 1970). A recent theoretical investigation (McNeil and Bethune, 1973) of dynamic sedimentation analysis has indicated its possible use in the simultaneous estimation of the molecular parameters, i.e., sedimentation and diffusion coefficients, governing such transport. This paper delineates the experimental application of these techniques to determination of the sedimentation and diffusion coefficients of ribonuclease A and chymotrypsinogen A. Materials Ribonuclease A was obtained as a phosphate-free lyophilized preparation from Worthington Biochemical Corp. (lot RAF 6080-90). Prior to use the protein was dissolved in p H 7.3, 0.01 M imidazole-0.1 M NaCl buffer and heated for 10 min a t 60' to dissociate polymers which may have been formed during lyophilization (Crestfield et at., 1962).
Journal of Nuclear Medicine, Jul 1, 1976
The diagnosis of acute pulmonary embolism has been plagued on the one extreme by the nonspeci fic... more The diagnosis of acute pulmonary embolism has been plagued on the one extreme by the nonspeci ficity of clinical signs and symptoms and at the other extreme by the morbidity and high financial cost associated with pulmonary angiography (1,2). Per fusion lung scanning is intermediate in this spectrum in that its ability to detect patients with embolic dis ease is extremely high, I 00% (3) , but its specificity is lower, varying with the findings present on the concomitant chest radiograph and ventilation study (4â€"10). This investigation suggests a diagnostic strategy for the evaluation of patients suspect for pulmonary embolism once the results of perfusion or ventilationâ€"perfusion studies are known. METHODS One hundred and five consecutive patients who had both pulmonary scintigraphy and angiography in the past 3 years were the subjects of this study. Seventy-seven percent of patients had angiograms within 24 hr of the lung scan, 87% within 48 hr, and 97% within 72 hr. The patients presented with a variety of symptoms, the most common being pleuritic chest pain or dyspnea. Perfusion studies in all patients, and ventilation studies in 52 patients, were performed as previously described (9). In particular, ventilation studies were performed after the perfusion study, in the projection
Reimbursement and Imaging Technology Assessment in the United States
Investigative Radiology, 1993
Hidden Barriers to Improvement in the Quality of Care
N Engl J Med, 2001
The public has just begun to recognize that despite the enormous achievements of American medicin... more The public has just begun to recognize that despite the enormous achievements of American medicine and the American health care system, the quality of care in this country needs to be and can be improved. Two recent reports from the Institute of Medicine ...
Office Laboratory Tests: Perceptions of Profitability
Medical Care, Mar 1, 1984
Theoretic modeling suggests that common office tests as a group are profitable. To determine whet... more Theoretic modeling suggests that common office tests as a group are profitable. To determine whether practicing internists perceive this profitability and whether their perceptions differ for different tests or for patients with different types of insurance coverage, the authors surveyed 111 physicians in private office practice. Respondents' estimates of receipts for tests done on patients with Medicare or Blue Cross/Blue Shield coverage were higher than their estimated costs for the testing. Estimates of receipts from Medicaid patients were lower than estimated costs of testing. After standardizing the estimated receipts from patients with different insurance coverages, the authors found that the average estimated profits for different tests on an "average insured patient" varied sixfold, from 5.99foranelectrocardiogramto5.99 for an electrocardiogram to 5.99foranelectrocardiogramto1.01 for a urinalysis. The authors suggest that perceived financial incentives are extremely variable by test. Different insurance coverages are perceived as providing varying financial incentives for testing; Medicaid provides a disincentive. Appropriate reform of the existing fee schedules should be selective by test and coverage.
Assessment of the Value of Scintigraphic Procedures: A Case Study
On distinguishing pulmonary embolism from other causes of pleuritic chest pain
Amer J Med, 1984
Biochemistry Usa, 1973
Computer generated concentration distributions have allowed the development of numerical techniqu... more Computer generated concentration distributions have allowed the development of numerical techniques for the determination of sedimentation and diffusion coefficients from the integrated Lamm equation; they are applicable to two component systems with minimal dependence of the characteristic parameters on concentration. Accuracy is assessed by B y their very nature, transport processes are dynamic, involving concentration changes in both time and space, the changes being determined by the molecular parameters governing transport in a given experimental system. Thus, for sedimentation in a sector-shaped cell with an imposed radially dependent field, concentration changes with respect to time are related to those with respect to space by the Lamm (1929) equation which, on differentiation of the right side, yields, if s and D are not functions of c where c is the concentration at time t and position r , I' is the distance in centimeters from the center of rotation, w is the angular velocity in radians per second, s is the sedimentation coefficient in seconds, and D is the diffusion coefficient in squared centimeters per second. For constant w, values of the derivatives, acjati,, aclar;,, a2cjb1'21 t , and of c at radius r and time t , i.e., c(r,t), are determined by the local values of s and D; conversely, their determination allows calculation of the s and D pertaining a t r. An integral formulation of eq l a similarly relates concentration changes ;.e., either accumulation or depletion of mass, over a finite segment of the liquid t From the
Catheterization and mortality in elderly patients with acute myocardial infarction
JAMA: The Journal of the American Medical Association, 1995
Critical Questions Regarding a New Diagnostic Technology: A Case Study Using Computerized Tomography of the Head
The patient's role in assessing the value of diagnostic tests
Radiology, 1979
Diagnostic tests are usually evaluated for their informational content and effect on health outco... more Diagnostic tests are usually evaluated for their informational content and effect on health outcomes. Yet patient attitudes toward taking risks and the morbid sequelae associated with either the diagnostic test or its consequences are seldom considered. The authors present a prototypical model which incorporates patient attitudes into the evaluative process. Based on traditional indices of test efficacy, preoperative searches for occult metastases in patients with presumably operable bronchogenic carcinoma should never be performed. However, if patient attitudes toward perioperative death are considered, many should have preoperative staging tests. The exact percentage of patients benefiting from testing varies with test sensitivity and specificity. This integrative approach is appropriate for oncologic patients who frequently undergo treatment.
A prospective study of computed tomography and ultrasound in the detection and staging of pelvic masses
Radiology, 1983
Findings from computed tomography (CT) and ultrasound (US) examinations of 74 patients who were c... more Findings from computed tomography (CT) and ultrasound (US) examinations of 74 patients who were clinically thought to have pelvic masses and of 110 patients who had possible recurrence of pelvic tumors were analyzed. There was no significant difference in the ability of the two modalities to identify masses or to predict disease extent. Although both CT and US failed to detect some examples of spread outside of the pelvis, overstaging (apart from two cases of unconfirmed parametrial spread) did not occur with CT and occurred only once with US. The sensitivity was 0.96 for CT and 0.91 for US in the detection of pelvic masses. Both modalities had an accuracy of 0.81 in the detection of recurrent disease.
Preoperative and follow-up bone scans in patients with primary carcinoma of the breast
Surgery, gynecology & obstetrics, 1978
We have attempted to evaluate the role of preoperative and postoperative bone scans in patients w... more We have attempted to evaluate the role of preoperative and postoperative bone scans in patients with localized carcinoma of the breast. The yield of positive preoperative scans in patients with Stages I and II disease is low and confounded by a relatively high percentage of false-positive results. Conversely, 16 per cent of patients with Stage III disease had evidence of bony metastasis at the time of operation. Positive bone scans were found three times as frequently in patients with axillary node involvement than in those without. Thirty per cent of those observed for varying times up to 41 months had evidence of bony metastases. Again, there was a correlation with initial clinical staging with 3.6 to 8.0 times more conversions in patients with Stage II or III disease than in those with Stage I disease. It appears that the majority of metastases to the bone become apparent within the first years. This observation deserves further study to elaborate the natural history of metastati...
Comparing a medical records-based and a claims-based index for measuring comorbidity in patients with lung or colon cancer
Journal of Geriatric Oncology, 2015
Ascertaining comorbid conditions in cancer patients is important for research and clinical qualit... more Ascertaining comorbid conditions in cancer patients is important for research and clinical quality measurement, and is particularly important for understanding care and outcomes for older patients and those with multi-morbidity. We compared the medical records-based ACE-27 index and the claims-based Charlson index in predicting receipt of therapy and survival for lung and colon cancer patients. We calculated the Charlson index using administrative data and the ACE-27 score using medical records for Veterans Affairs patients diagnosed with stage I/II non-small cell lung or stage III colon cancer from January 2003 to December 2004. We compared the proportion of patients identified by each index as having any comorbidity. We used multivariable logistic regression to ascertain the predictive power of each index regarding delivery of guideline-recommended therapies and two-year survival, comparing the c-statistic and the Akaike information criterion (AIC). Overall, 97.2% of lung and 90.9% of colon cancer patients had any comorbidity according to the ACE-27 index, versus 59.5% and 49.7%, respectively, according to the Charlson. Multivariable models including the ACE-27 index outperformed Charlson-based models when assessing receipt of guideline-recommended therapies, with higher c-statistics and lower AICs. Neither index was clearly superior in prediction of two-year survival. The ACE-27 index measured using medical records captured more comorbidity and outperformed the Charlson index measured using administrative data for predicting receipt of guideline-recommended therapies, demonstrating the potential value of more detailed comorbidity data. However, the two indices had relatively similar performance when predicting survival.
Hospital Response to DRG-Based Prospective Payment
Medical Decision Making, 1985
The introduction of the Medicare Prospective Payment System (PPS) is markedly influencing the env... more The introduction of the Medicare Prospective Payment System (PPS) is markedly influencing the environment in which hospitals care for patients, teach medical students and residents, and perform clinical research. Hospitals, particularly teaching institutions, are responding to this challenge by developing new management reports, by analyzing physicians' practice patterns, and by estimating more precisely the fixed and variable costs of various ancillary services. The common objective of these activities is to improve our knowledge of clinical practices, and thereby improve decisions relating to the cost-effectiveness and quality of care delivered to patients in the hospital.
Trends in the use of drag therapies in patients with acute myocardial infarction: 1988 to 1992
Journal of the American College of Cardiology, 1994
Results. The overall thrombolysis rate for patients with acute myocardial infarction increased fr... more Results. The overall thrombolysis rate for patients with acute myocardial infarction increased from 11% in fiscal year 1988 to 18% in fiscal year 1990 and has remained approximately at that level since then. In mid-1989, tissue plasminogen activator was used in 90% of the ...
Brigham and Women's Hospital Handbook of Diagnostic Imaging
Radiology
Basically there are 62 sections on some of the most common dilemmas dealt with. These are followe... more Basically there are 62 sections on some of the most common dilemmas dealt with. These are followed by four interesting appendixes. The clinical sections are grouped under eight headings: abdominal disease (12 sections), genito-urinary disease (seven), chest ...
Radiology, 2017
In both the United States and Europe, efforts to reduce soaring health care costs have led to int... more In both the United States and Europe, efforts to reduce soaring health care costs have led to intense scrutiny of both standard and innovative uses of imaging. Given that the United States spends a larger share of its gross domestic product on health care than any other nation and also has the most varied health care financing and delivery systems in the world, it has become an especially fertile environment for developing and testing approaches to controlling health care costs and value. This report focuses on recent reforms that have had a dampening effect on imaging use in the United States and provides a glimpse of obstacles that imaging practices may soon face or are already facing in other countries. On the basis of material presented at the 2015 meeting of the International Society for Strategic Studies in Radiology, this report outlines the effects of reforms aimed at (a) controlling imaging use, (b) controlling payer expense through changes in benefit design, and (c) contro...
Probabilistic sensitivity analysis using Monte Carlo simulation
The data for medical decision analyses are often unreliable. Traditional sensitivity analysis--va... more The data for medical decision analyses are often unreliable. Traditional sensitivity analysis--varying one or more probability or utility estimates from baseline values to see if the optimal strategy changes--is cumbersome if more than two values are allowed to vary concurrently. This paper describes a practical method for probabilistic sensitivity analysis, in which uncertainties in all values are considered simultaneously. The uncertainty in each probability and utility is assumed to possess a probability distribution. For ease of application we have used a parametric model that permits each distribution to be specified by two values: the baseline estimate and a bound (upper or lower) of the 95 percent confidence interval. Following multiple simulations of the decision tree in which each probability and utility is randomly assigned a value within its distribution, the following results are recorded: (a) the mean and standard deviation of the expected utility of each strategy; (b) the frequency with which each strategy is optimal; (c) the frequency with which each strategy "buys" or "costs" a specified amount of utility relative to the remaining strategies. As illustrated by an application to a previously published decision analysis, this technique is easy to use and can be a valuable addition to the armamentarium of the decision analyst.
Ordering Tests in the United States and England-Reply
Jama, Apr 5, 1985
Biochemistry Usa, 1973
Numerical methods have been developed for rapid simultaneous determination of sedimentation and d... more Numerical methods have been developed for rapid simultaneous determination of sedimentation and diffusion coefficients from transient state sedimentation analyses based on computer simulated data. Application of this methodology to experimental data obtained for ribonuclease A and chymotrypsinogen A demonstrates that the values of the sedimenta-S edimentation in the ultracentrifuge occurs in a sectorshaped cell in a nonuniform force field; resulting concentration changes as functions of time and space are described by the mass conservation equation (Lamm, 1929) Few explicit experimental attempts have utilized the dynamic aspects of this formulation in their totality although measurements of concentration changes with time throughout the liquid column have been used in the determination of the sedimentation coefficient of thallous sulfate (Creeth, 1962), and evaluation of such changes at the air-liquid meniscus has led to the development of several different approaches to determination of molecular weights of macromolecules (LaBar, 1965 ; Charlwood, 1967; Simpson and Bethune, 1970). A recent theoretical investigation (McNeil and Bethune, 1973) of dynamic sedimentation analysis has indicated its possible use in the simultaneous estimation of the molecular parameters, i.e., sedimentation and diffusion coefficients, governing such transport. This paper delineates the experimental application of these techniques to determination of the sedimentation and diffusion coefficients of ribonuclease A and chymotrypsinogen A. Materials Ribonuclease A was obtained as a phosphate-free lyophilized preparation from Worthington Biochemical Corp. (lot RAF 6080-90). Prior to use the protein was dissolved in p H 7.3, 0.01 M imidazole-0.1 M NaCl buffer and heated for 10 min a t 60' to dissociate polymers which may have been formed during lyophilization (Crestfield et at., 1962).
Journal of Nuclear Medicine, Jul 1, 1976
The diagnosis of acute pulmonary embolism has been plagued on the one extreme by the nonspeci fic... more The diagnosis of acute pulmonary embolism has been plagued on the one extreme by the nonspeci ficity of clinical signs and symptoms and at the other extreme by the morbidity and high financial cost associated with pulmonary angiography (1,2). Per fusion lung scanning is intermediate in this spectrum in that its ability to detect patients with embolic dis ease is extremely high, I 00% (3) , but its specificity is lower, varying with the findings present on the concomitant chest radiograph and ventilation study (4â€"10). This investigation suggests a diagnostic strategy for the evaluation of patients suspect for pulmonary embolism once the results of perfusion or ventilationâ€"perfusion studies are known. METHODS One hundred and five consecutive patients who had both pulmonary scintigraphy and angiography in the past 3 years were the subjects of this study. Seventy-seven percent of patients had angiograms within 24 hr of the lung scan, 87% within 48 hr, and 97% within 72 hr. The patients presented with a variety of symptoms, the most common being pleuritic chest pain or dyspnea. Perfusion studies in all patients, and ventilation studies in 52 patients, were performed as previously described (9). In particular, ventilation studies were performed after the perfusion study, in the projection
Reimbursement and Imaging Technology Assessment in the United States
Investigative Radiology, 1993
Hidden Barriers to Improvement in the Quality of Care
N Engl J Med, 2001
The public has just begun to recognize that despite the enormous achievements of American medicin... more The public has just begun to recognize that despite the enormous achievements of American medicine and the American health care system, the quality of care in this country needs to be and can be improved. Two recent reports from the Institute of Medicine ...
Office Laboratory Tests: Perceptions of Profitability
Medical Care, Mar 1, 1984
Theoretic modeling suggests that common office tests as a group are profitable. To determine whet... more Theoretic modeling suggests that common office tests as a group are profitable. To determine whether practicing internists perceive this profitability and whether their perceptions differ for different tests or for patients with different types of insurance coverage, the authors surveyed 111 physicians in private office practice. Respondents' estimates of receipts for tests done on patients with Medicare or Blue Cross/Blue Shield coverage were higher than their estimated costs for the testing. Estimates of receipts from Medicaid patients were lower than estimated costs of testing. After standardizing the estimated receipts from patients with different insurance coverages, the authors found that the average estimated profits for different tests on an "average insured patient" varied sixfold, from 5.99foranelectrocardiogramto5.99 for an electrocardiogram to 5.99foranelectrocardiogramto1.01 for a urinalysis. The authors suggest that perceived financial incentives are extremely variable by test. Different insurance coverages are perceived as providing varying financial incentives for testing; Medicaid provides a disincentive. Appropriate reform of the existing fee schedules should be selective by test and coverage.
Assessment of the Value of Scintigraphic Procedures: A Case Study
On distinguishing pulmonary embolism from other causes of pleuritic chest pain
Amer J Med, 1984
Biochemistry Usa, 1973
Computer generated concentration distributions have allowed the development of numerical techniqu... more Computer generated concentration distributions have allowed the development of numerical techniques for the determination of sedimentation and diffusion coefficients from the integrated Lamm equation; they are applicable to two component systems with minimal dependence of the characteristic parameters on concentration. Accuracy is assessed by B y their very nature, transport processes are dynamic, involving concentration changes in both time and space, the changes being determined by the molecular parameters governing transport in a given experimental system. Thus, for sedimentation in a sector-shaped cell with an imposed radially dependent field, concentration changes with respect to time are related to those with respect to space by the Lamm (1929) equation which, on differentiation of the right side, yields, if s and D are not functions of c where c is the concentration at time t and position r , I' is the distance in centimeters from the center of rotation, w is the angular velocity in radians per second, s is the sedimentation coefficient in seconds, and D is the diffusion coefficient in squared centimeters per second. For constant w, values of the derivatives, acjati,, aclar;,, a2cjb1'21 t , and of c at radius r and time t , i.e., c(r,t), are determined by the local values of s and D; conversely, their determination allows calculation of the s and D pertaining a t r. An integral formulation of eq l a similarly relates concentration changes ;.e., either accumulation or depletion of mass, over a finite segment of the liquid t From the