Biomedical subjects

M Helfand

Publications and source records attributed to M Helfand.

5 recordsLinked to original sources

PubMed1992

A decision analysis of traumatic splenic injuries.

We created a decision analysis model of the nonsurgical management of traumatic splenic injuries to clarify the risk of hospital survival, overwhelming postsplenectomy infection (OPSI) deaths, and transfusion-related deaths. We reviewed 72 cases of splenic injury at our institution to identify our transfusion requirements for successful observation (0.5 units), observation failure (1.0 units), and surgical splenic management (1.6 units). Using our model and baseline probabilities determined from the literature, we compared the nonsurgical management of splenic injuries with immediate laparotomy and found an increase in hospital survival with observation, but an over two-fold increase in the risk of transfusion-related death. The OPSI deaths were not markedly different between the two strategies. Overall, we found decision analysis useful in identifying important variables such as the probability of nontherapeutic laparotomy death or missed injury, and in clarifying the risk of the nonsurgical management of splenic injuries with regard to transfusion-related deaths and OPSI deaths.

Blood Transfusion↗

PubMed1992

Effect of the Clinical Laboratory Improvement Amendments of 1988 (CLIA '88) on the incidence of invasive cervical cancer.

The Clinical Laboratory Improvement Act of 1988 (CLIA '88) mandates strict, new quality-control measures for laboratories that interpret cervical cytology smears. Proposed regulations include proficiency testing of cytotechnologists and remediation for technologists and laboratories that fail to meet proposed proficiency standards. Proponents of the new regulations argue that these measures will reduce deaths from cervical cancer by reducing the false-negative rate of the Papanicolaou (Pap) test, but opponents argue that the regulations will increase the price of processing Pap tests and thereby reduce access to cervical cancer screening for high-risk, vulnerable populations. To examine these claims the authors used David Eddy's published simulation to model the natural history and detection of cervical neoplasia, and developed a new model to examine the health consequences of diminished access to Pap testing. The authors estimated the false-negative rate of the Pap test and the price elasticity of demand for preventive services on the basis of the published literature, and modeled the entire range of published or quoted predictions about the impact of CLIA '88 on accuracy and price. The results show that, if effects on access are ignored, reducing the false-negative rate from 15% to 5% would prevent 66 invasive cancers per 100,000 average risk women screened. However, under moderate assumptions regarding the effect of price on access, the regulations would prevent only 11 (instead of 66) cancers per 100,000 eligible women. The regulatory effect is very sensitive to the degree of improvement in the false-negative rate and increase in price that the regulations cause. Over the range of assumptions and predictions encountered in the literature and tested in our analysis, the proposed regulations could greatly reduce or greatly increase the incidence of invasive cancer, especially among high-risk and uninsured women. The implementation of the regulations should be delayed until new information regarding the actual false-negative rate of the Pap test allow a more precise estimate of the potential impact on the incidence of cervical cancer.

Clinical Competence↗

PubMed1990

Monitoring therapy in patients taking levothyroxine.

PURPOSE: To evaluate the use of thyroid function tests to monitor therapy in patients taking levothyroxine. DATA IDENTIFICATION: Studies published between 1966 and January 1990 were identified through computer searches and references of identified studies. STUDY SELECTION: Studies that included a careful description of the patients under study, well-defined interventions, and a meaningful criterion standard were emphasized. DATA EXTRACTION: Data from different studies were combined to estimate the probability of positive and negative test results in well-defined clinical situations. Informal methods of synthesizing evidence were used when combining data from different studies was not justified. RESULTS: The sensitive thyrotropin (TSH) test is the preferred method to monitor therapy because it agrees with physiologic measures of thyroid hormone effect. Among clinically euthyroid patients who take 100 to 150 micrograms/d of levothyroxine, the probability that the sensitive thyrotropin will be undetectable is close to 50%. These patients are most likely to benefit from testing. Patients who take over 250 micrograms/d are almost certain to have undetectable sensitive thyrotropin levels; in these patients, the dose may be lowered without testing. CONCLUSIONS: Adequate long-term studies are needed to determine the role of biochemical testing in monitoring therapy. Current evidence suggests that the sensitive thyrotropin test should be used to monitor therapy. Clinically euthyroid patients taking lower dosages of levothyroxine are most likely to benefit from testing.

Humans↗

PubMed1990

Screening for thyroid disease.

PURPOSE: To evaluate the usefulness of screening for thyroid dysfunction in various clinical settings. DESIGN: Review and synthesis of the literature. MAIN RESULTS: Screening in the community detects new overt thyrotoxicosis or hypothyroidism in approximately 0.5% of the general population. The yield is best among women over 40 years of age (1%) and is lowest among young men (0%). Case-finding (testing clinic patients who are seeing a physician for unrelated reasons) has a better yield and is less expensive than screening in the community. Patients hospitalized with acute illnesses do not benefit from routine thyroid function testing. However, patients who are admitted to specialized geriatric units because of general disability, failure to thrive, and other indications may benefit. In various studies, from 2% to 5% of patients admitted to geriatric units have treatable thyroid disease. The serum total thyroxine, free thyroxine index, free thyroxine, and sensitive thyrotropin assay are all effective as initial tests for screening. The sensitive thyrotropin assay is less cost-effective than the other choices. RECOMMENDATIONS: Case-finding in some women over 40 years of age can be useful. Patients admitted to specialized geriatric units may also benefit from routine testing. Thyroid function tests are not indicated for community screening programs or for patients hospitalized with acute medical or psychiatric illnesses.

Adult↗

PubMed1985

Factors involved in the interpretation of fetal monitor tracings.

In order to study how physicians choose to use electronic fetal monitoring and interpret tracings, we administered a questionnaire to which 107 practicing obstetricians and 11 experts in electronic fetal monitoring responded. Sixty-one (57%) of the respondents monitored more than half of their deliveries (high users). In comparison to the less frequent users of electronic fetal monitoring (low users), they showed more positive attitudes toward electronic fetal monitoring and were nearly always more likely to perform cesarean sections on hypothetical patients described in the questionnaire. These differences appeared to be due to the high users' higher estimate of danger to the fetus. We also found that most physicians were generally more likely to perform a cesarean section on a high-risk mother than a low-risk mother with the same tracing. The majority of high and low users and nearly all of the experts, however, felt that antepartum risk factors are not of value in deciding what to do about an abnormal tracing. We conclude that there is wide variation in the way in which obstetricians use, interpret, and act on electronic fetal monitoring tracings. Some of these differences may be due to differing attitudes toward electronic fetal monitoring, differences in interpretation of electronic fetal monitoring tracings, and differences in the way obstetricians incorporate maternal risk factors into their decision-making.

Attitude of Health Personnel↗