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Biomedical subjects

A I Mushlin

Publications and source records attributed to A I Mushlin.

At least 37 records · Page 2Linked to original sources
PubMed1996

The effect of spectrum bias on the utility of magnetic resonance imaging and evoked potentials in the diagnosis of suspected multiple sclerosis.

BACKGROUND: Spectrum bias is the tendency for the effectiveness of a test (or treatment) to vary as a function of clinical, pathologic, or comorbid variables including disease severity. Our null hypothesis was that within the population of suspected multiple sclerosis (MS) patients, there would be no difference in MRI and evoked potential (EP) sensitivity and specificity between those with mild MS versus those with more severe clinical signs of the disease, i.e., that spectrum bias is not a factor. METHODS: Three hundred three patients with suspected MS were evaluated by a board-certified neurologist, then scanned with MRI. Two hundred four patients also received EP testing. RESULTS: The sensitivity of MRI in patients with suspected MS was 58 percent with a false-positive rate of 9%. The overall sensitivity was 64% in the probable and 45% in the possible group. In the low pretest probability group sensitivity was 20%, and it was 70% in the high pretest probability group. These differences in sensitivity are statistically significant (p < 0.03). In contrast, the specificity between groups did not differ significantly. EP sensitivity was 69% in the high probability subgroup and 5% in the low probability subgroup. (p < 0.01). CONCLUSION: In this study, both EP and MRI results demonstrated an association between disease frequency, disease severity, and test sensitivity with greater disease frequency and intensity suggesting more impressive diagnostic test performance. The distorting effect of the variable clinical severity on MRI and EP sensitivity in suspected MS underscores that diagnostic tests perform differently in different groups of patients.

Bias↗
PubMed1994

Clinical diagnosis of multiple sclerosis. The impact of magnetic resonance imaging and ancillary testing. Rochester-Toronto Magnetic Resonance Study Group.

OBJECTIVE: Magnetic resonance imaging, computed tomography, cerebrospinal fluid analysis, and evoked potential testing are used to assist in the diagnosis of patients suspected to have multiple sclerosis (MS). The impact of these tests on a clinician's diagnosis of patients suspected to have MS has not been studied systematically. DESIGN: Clinicians made a diagnosis of each patient following clinical evaluation, again after reviewing the results of magnetic resonance imaging, and finally after reviewing information from other laboratory testing. These diagnoses were compared with the criterion standard of a masked "gold standard" panel reviewing all information after a mean follow-up of 0.9 year. SETTING: The General Neurology Clinic and Multiple Sclerosis Clinic of the University of Rochester (NY). PATIENTS: A consecutive sample of 62 patients diagnosed as having either possible or probable MS following clinical evaluation. MAIN OUTCOME MEASURE: Changes in diagnostic certainty of clinicians following incremental presentation of new laboratory data and the accuracy of such diagnoses. RESULTS: Clinicians used magnetic resonance imaging findings to diagnose definite MS or to eliminate MS from diagnostic consideration in 44% of cases. In these cases, further laboratory testing did not alter clinicians' decisions. In the remaining 56% of cases, in which magnetic resonance imaging did not lead to a diagnosis of definite MS or eliminate MS from diagnostic consideration, further laboratory testing led to such diagnoses in an additional 13% of cases. Gold standard diagnoses were in agreement with the clinician's assessments. CONCLUSIONS: Magnetic resonance imaging aids in the evaluation of patients suspected to have MS; other subsequent studies (computed tomography, cerebrospinal fluid analysis, and evoked potential testing) have less impact. After all studies are performed, about half of such patients still have a tentative diagnosis.

Adult↗
PubMed1994

The value of diagnostic information to patients with suspected multiple sclerosis. Rochester-Toronto MRI Study Group.

OBJECTIVE: To determine the value of diagnostic information to patients with suspected multiple sclerosis (MS). Because treatment choices would be only minimally affected by earlier diagnosis for most patients with this clinical problem, this study assessed the "nondecisional" value of diagnosis. DESIGN: Prospective survey of patients before and after diagnostic workup, including imaging with magnetic resonance scanning. We assessed the effect of diagnostic information on patients' sense of well-being, as well as direct measures of the utility of information (using time trade-off and willingness-to-pay techniques). SETTING: Patients referred from primary care practices for diagnostic workup for suspected MS to neurology clinics and practices. PATIENTS: Sixty-eight individuals, mean age 37.5 years, 53 female and 15 male. Thirty-one patients were classified as having "probable MS," and 37 were classified as having "possible MS" by the examining neurologist before workup. MEASUREMENTS: Present and future health perception, uncertainty about diagnosis-prognosis, and level of anxiety. Willingness to pay for diagnostic information, quality of life as measured by the time trade-off technique, and psychological state of the patient before and after diagnosis. RESULTS: Diagnostic uncertainty fell significantly as a result of the diagnostic workup. Most patients (59/62) said that they were better off having received diagnostic information. Although anxiety seemed to be reduced by testing, overall anxiety levels did not decrease as much as anticipated. Patients also became less optimistic about their future health after testing. On average, patients were willing to forgo 4.5 quality-adjusted life days to receive an earlier diagnosis and their quality of life after diagnosis improved slightly. Subgroups of patients differed in their response to diagnostic information. Those in whom no definitive diagnosis emerged tend to be more anxious rather than being reassured by the "negative" workup. Individuals with "positive" workups became less anxious and expressed favorable feelings about the diagnostic workup even though they often faced a chronic disease. CONCLUSIONS: Overall, the diagnostic workup seemed to benefit patients and improve their sense of well-being. However, whether the effects were beneficial or not depended on the results of the diagnostic workup itself. In clinical practice the decision to undergo testing in situations in which definitive treatment is unavailable should be individualized. The potential for negative as well as positive consequences should be recognized.

Adult↗
PubMed1994

Diagnosing pedal osteomyelitis: testing choices and their consequences.

OBJECTIVE: To compare the efficacies and cost-effectiveness of four strategies for the management of suspected pedal osteomyelitis in the setting of vascular impairment: 1) therapeutic trial of short-term antibiotics for presumed cellulitis without osteomyelitis (short); 2) technetium bone scanning followed by either short-term therapy if negative or either a biopsy or aggressive long-term intravenous therapy if positive (scan); 3) bone biopsy followed by long-term intravenous therapy if positive or short-term therapy if negative (biopsy); and 4) immediate long-term intravenous antibiotics for presumed osteomyelitis (long). DESIGN: Decision analysis and cost-effectiveness analysis with sensitivity analyses. The main outcomes states are amputation and the resource expenditures associated with bone scans, biopsies, and therapies. DATA SOURCES: The authors obtained estimates of test accuracy from literature review and summarized them using newly developed meta-analytic techniques. MAIN RESULTS: The optimal decision depends heavily on the estimated probability of osteomyelitis at presentation. At very low probabilities, the short-term strategy is preferred. When the probability of osteomyelitis is from 2% to 8%, the lowest amputation rate occurs when one does a diagnostic scan. From 8% to 50%, the best outcomes follow biopsy. At probabilities higher than 50%, the preferred strategy is long-term antibiotics. However, the differences in outcomes are quite small even when osteomyelitis is a virtual certainty. CONCLUSIONS: Over the whole range of prior probabilities, the short-term strategy is the least expensive. At very low probabilities, it dominates the other strategies. When the likelihood of osteomyelitis is higher (10-20%), scanning results in outcomes and cost-effectiveness ratios comparable to those of immediate biopsy and is less invasive. When the probability of osteomyelitis is 50%, biopsy is quite cost-effective compared with all the other strategies (cost-effectiveness ratio = $15,502 per amputation averted) and is preferred to the scan strategy. When the confidence that a patient has osteomyelitis is very high (> 90% probability), the improved outcomes associated with long-term antibiotics are achieved with little additional expense and with favorable cost-effectiveness ratios compared with those of the other strategies.

Anti-Bacterial Agents↗
PubMed1992

Is screening for breast cancer cost-effective?

As the toll taken by breast cancer continues unabated, screening programs are widely perceived to play a critical role to improve diagnosis and successful treatment. Breast cancer screening programs are increasingly promoted to women; however, the economic implications of mass screening is a subject of much health policy debate. Cost-effectiveness analysis is an economic methodology widely used to inform such decisions, yet there is a dearth of information available on the economic consequences of mass breast cancer screening. The authors evaluated nine breast cancer screening cost-effectiveness studies that are based on computer simulations, observational trial data, or a combination of both. The results of these studies, conducted in the United States and other countries, indicate that the cost-effectiveness of screening for breast cancer generally compares favorably with other expenditures in the health-care field, although screening younger women does not appear to be as favorable. However, there is considerable variability in the methodology used and a need for more comprehensive research in this area.

Adult↗
PubMed1991

The necessary length of hospital stay for chronic pulmonary disease.

OBJECTIVE: --To determine the necessary length of stay for patients admitted to the hospital with an exacerbation of chronic pulmonary disease and to compare this with the length of stay assigned by the diagnosis related group system. DESIGN: --A cohort of patients were followed up prospectively after hospital admission to determine when complications, critical incidents, and the need for monitoring occurred. The medically derived necessary lengths of stay were statistically compared with the lengths of stay assigned by the diagnosis related group. Clinical factors were used to predict long vs short necessary lengths of stay. SETTING: --Two acute care hospitals: one was the principal and the other a major community teaching hospital. PATIENTS: --A consecutive sample of 83 patients who were 45 years of age or older and who required admission for treatment of chronic pulmonary disease. MAIN OUTCOME MEASURES: --The occurrence and time of complications, critical interventions, and monitoring. RESULTS: --After 6 days in the hospital, 90% of patients were free of complications or the need for monitoring. However, 16 days elapsed before 90% of patients had been discharged from the hospital. The length of stay that was considered necessary for care averaged 6.9 days; the actual mean length of stay was 8.7 days. The correlation between each patient's ideal length of stay and the length of stay assigned by the diagnosis related group was low and was not statistically significant. Three clinical variables at the time of admission (high PCO2 levels, symptoms that were present for more than 1 day, and antibiotic treatment) were associated with the need for longer hospital stays. CONCLUSIONS: --The medically required length of stay for patients with an exacerbation of chronic pulmonary disease was between 6 and 7 days, on average. This length of stay, which was based on clinical events, differs from the length of stay that was calculated as a statistical norm by the diagnosis related group system. Clinical characteristics may help to identify patients who require a longer length of stay.

Aged↗
PubMed1991

On the (near) equivalence of cost-effectiveness and cost-benefit analyses.

Many people believe that cost-effectiveness (CE) and cost-benefit (CB) analyses require different assumptions. However, when CE analysis supports decisions to use medical resources, it makes the same assumptions that CB analysis requires. They are mathematically equivalent. Differences between CE and CB hinge more on reporting style than on fundamental assumptions.

Cost-Benefit Analysis↗
PubMed1989

Intravenous pyelography: the case against its routine use.

PURPOSE: To critically appraise four common uses of intravenous pyelography in adults. DATA IDENTIFICATION: We reviewed the literature on the use of intravenous pyelography for four clinical indications. STUDY SELECTION: We analyzed the literature to determine the proportion of intravenous pyelograms producing clinically useful information (yield) in four clinical situations. The best estimate of its accuracy (sensitivity and specificity) for associated pathologic findings was determined. The implications of using the test on the outcomes of patients and costs were evaluated. RESULTS OF DATA SYNTHESIS: The yield of significant abnormalities in patients having prostatectomy is small; intravenous pyelography does not specifically indicate ureteral obstruction, and is not sensitive or specific enough for screening for urinary tract malignancies. Many false-positive results, little benefit, and significant costs can be expected. When used before hysterectomy, intravenous pyelography does not reduce injury to the ureters, and the yield of unexpected abnormalities is small. The use of the test to screen for unexpected anatomic abnormalities in adult women after urinary tract infections has not led to improved outcomes or prevention of impaired renal function. Acquired causes of obstruction will be suggested by the history or physical examination. In hypertensive adults, intravenous pyelography is not accurate enough in detecting renal artery stenosis or in predicting favorable outcomes of renal artery surgery. Also, large costs are generated by high false-positive rates, and candidates for successful surgery are not reliably identified. CONCLUSIONS: Selective use of intravenous pyelography is recommended for patients before prostatectomy or hysterectomy, in women after urinary tract infections, and in adults whose hypertension may have a renovascular cause. Use should be reserved for patients whose history and physical examination raise specific questions for which this test could provide an answer that would affect treatment.

Cost-Benefit Analysis↗
PubMed1988

Quality of care during a community-wide experiment in prospective payment to hospitals.

To determine whether a community-wide experiment in hospital prospective payment adversely affected quality of care, availability and outcomes of care were studied in Rochester, NY from 1980 to 1984. During this 5-year period, prospective payment contained hospital expenditures in a community that was already below the national average in health-care costs. Access to necessary care was maintained, and there were increased admissions for management of maternal illness and acute myocardial infarction. Rates of inpatient elective surgery declined. Outcomes of care remained stable, including neonatal deaths, ischemic heart disease deaths, deaths from five selected surgical conditions, and rates of adverse outcomes from sentinel medical and surgical conditions. These results indicated that prospective payment programs in which incentives to decrease marginal or unneeded care are linked with a community-wide effort to plan for the delivery of services can be financially and clinically successful.

Abdomen, Acute↗
PubMed1986

How well does the activated partial thromboplastin time predict postoperative hemorrhage?

To determine the clinical usefulness of the activated partial thromboplastin time in screening patients before surgery, we related preoperative test results to the occurrence of hemorrhagic complications, studying all adult inpatients undergoing invasive diagnostic or therapeutic procedures at a large university hospital during a one-year period. Using clinical characteristics to divide the population into two groups according to a priori risk of hemorrhagic complications, we found that the activated partial thromboplastin time had no ability to predict the occurrence or absence of hemorrhage in the low-risk group, but that it was a predictor of modest strength in the high-risk group. Our data justify limiting preoperative coagulation screening to patients with active bleeding, known or clinically suspected bleeding disorders (including use of anticoagulants), liver disease, malabsorption, malnutrition, or other conditions associated with acquired coagulopathies and patients whose procedures may interfere with normal coagulation.

Adult↗
PubMed1986

Calculating the costs of training in primary care.

The costs of postgraduate medical education remain a relevant topic for educators and managers as well as for the payors of medical care. Historically, the pervasive problem has been that of identifying education costs in a program that jointly produces patient services and research as well as training. This problem is often approached by an accounting "allocation" of program costs to education. The previous literature on calculating the costs of medical education is reviewed in this paper and the theory related to joint product costing presented as an alternative to the accounting approach. A discussion of the issue centered around an example selected from a teaching hospital outpatient practice is presented.

Costs and Cost Analysis↗
PubMed1986

The utility of routine chest radiographs.

Although admission and preoperative chest radiography has been done for many years in various settings, existing data do not support its utility in enhancing patient care. Calculations based on estimates of the accuracy of chest radiographs and the likelihood of disease suggest that routine chest radiography may result in many more misleading than helpful results. Patients in whom chest radiographs are likely to improve outcome are best identified by a careful history and physical examination. We recommend that the practice of doing routine chest radiographs on admission and preoperatively be stopped and that the procedure be reserved for patients with clinical evidence of chest disease and patients having intrathoracic surgery.

Adult↗
PubMed1985

Early clinical signs identify low-risk patients with acute upper gastrointestinal hemorrhage.

Early identification of patients at low risk for poor outcome after acute upper gastrointestinal hemorrhage would allow reduction of diagnostic and therapeutic interventions. We identified six early predictors of good outcome: age less than 75 years, no unstable comorbid illness, no ascites found on physical examination, normal prothrombin time, and, within an hour after presentation, systolic blood pressure of 100 mm Hg or greater and nasogastric aspirate free of fresh blood. Presence of all six predictors defined the low-risk population. Among 162 patients in the development and retrospective validation phases of our study, all 74 low-risk patients had good outcomes. A prospective validation study of 111 patients further established the accuracy of our predictive method; only two of 52 low-risk patients had poor outcomes. Application of our method should allow more selective management of patients with acute upper gastrointestinal hemorrhage.

Acute Disease↗
PubMed1985

Diagnostic tests in breast cancer. Clinical strategies based on diagnostic probabilities.

Optimal diagnostic strategies used in screening for breast cancer and evaluating breast masses depend on the likelihood of malignancy, findings at physical examination, and the accuracy of tests and procedures. Results from published series, in conjunction with calculations of the probability of malignancy based on test results, indicate that only mammography is needed for screening. A clinical sequence for evaluating palpable breast masses should include a combination of mammography, ultrasound examination, and needle aspiration. In patients with negative findings, the probability of cancer will be sufficiently low to obviate the need for immediate surgical biopsy. However, if there are positive findings, or the initial clinical likelihood of malignancy is high, excision of the mass is indicated.

Adult↗