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Biomedical subjects

M Helfand

Publications and source records attributed to M Helfand.

49 records · Page 3Linked 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↗
PubMedDate not supplied

Outcome of hospitalized injured patients after institution of a trauma system in an urban area.

OBJECTIVE: To determine if risk of death for hospitalized injured patients changes when an urban trauma system is implemented. DESIGN: An analysis of the risk of death in hospitalized injured patients in 1984 and 1985 (pretrauma system), 1986 and 1987 (early trauma system), and 1990 and 1991 (established trauma system) using hospital discharge abstract data. SETTING: A total of 18 acute care hospitals in the four-county area encompassing Portland, Ore. PATIENTS: A cohort of 70,350 hospitalized patients with at least one discharge diagnosis indicating injury. MAIN OUTCOME MEASURE: Death during hospitalization. RESULTS: After the trauma system was established, 77% of patients in the region with an Injury Severity Score (ISS) of 16 or greater were admitted to level I trauma centers. More than 72% of patients with an ISS less than 16 were hospitalized in nontrauma centers. Risk of death for injured patients hospitalized at level I trauma centers declined after the trauma system was established (odds ratio, 0.65; 95% confidence interval, 0.51 to 0.81). Patients who died in trauma centers after institution of the trauma system were younger and had more severe injuries, and the majority died within 1 day of admission, whereas patients who died in nontrauma centers died a median of 5 days after admission. CONCLUSION: Establishment of a trauma system shifted the more seriously injured patients to level I trauma centers, where there was a significant reduction in the adjusted death rate.

Adolescent↗
PubMedDate not supplied

Universal newborn hearing screening: summary of evidence.

CONTEXT: Each year, approximately 5000 infants are born in the United States with moderate-to-profound, bilateral permanent hearing loss (PHL). Universal newborn hearing screening (UNHS) has been proposed as a means to speed diagnosis and treatment and thereby improve language outcomes in these children. OBJECTIVES: To identify strengths, weaknesses, and gaps in the evidence supporting UNHS and to compare the additional benefits and harms of UNHS with those of selective screening of high-risk newborns. DATA SOURCES: We searched the MEDLINE, CINAHL, and PsychINFO databases for relevant articles published from 1994 to August 2001, using terms for hearing disorders, infants or newborns, screening, and relevant treatments. We contacted experts and reviewed reference lists to identify additional articles, including those published before 1994. STUDY SELECTION: We included controlled and observational studies of (1) the accuracy, yield, and harms of screening using otoacoustic emissions (OAEs), auditory brainstem response (ABR), or both in the general newborn population and (2) the effects of screening or early identification and treatment on language outcomes. Of an original 340 articles identified, 19 articles, including 1 controlled trial, met these inclusion criteria. DATA EXTRACTION: Data on population, test performance, outcomes, and methodological quality were extracted by 2 authors (D.C.T., H.M.) using prespecified criteria developed by the US Preventive Services Task Force. We queried authors when information needed to assess study quality was missing. DATA SYNTHESIS: Good-quality studies show that from 2041 to 2794 low-risk and 86 to 208 high-risk newborns were screened to find 1 case of moderate-to-profound PHL. The best estimate of positive predictive value was 6.7%. Six percent to 15% of infants who are missed by the screening tests are subsequently diagnosed with bilateral PHL. In a trial of UNHS vs clinical screening at age 8 months, UNHS increased the proportion of infants with moderate-to-severe hearing loss diagnosed by age 10 months (57% vs 14%) but did not reduce the rate of diagnosis after age 18 months. No good-quality controlled study has compared UNHS with selective screening of high-risk newborns. In fair- to poor-quality cohort studies, intervention before age 6 months was associated with improved language and communication skills by ages 2 to 5 years. These studies had unclear criteria for selecting subjects, and none compared an inception cohort of low-risk newborns identified by screening with those identified in usual care, making it impossible to exclude selection bias as an explanation for the results. In a mathematical model based on the literature review, we estimated that extending screening to low-risk infants would detect 1 additional case before age 10 months for every 1441 low-risk infants screened, and result in treatment before 10 months of 1 additional case for every 2401 low-risk infants screened. With UNHS, 254 newborns would be referred for audiological evaluation because of false-positive second-stage screening test results vs 48 for selective screening. CONCLUSIONS: Modern screening tests for hearing impairment can improve identification of newborns with PHL, but the efficacy of UNHS to improve long-term language outcomes remains uncertain.

Evidence-Based Medicine↗
PubMedDate not supplied

Oregon trauma system: change in initial admission site and post- admission transfer of injured patients.

OBJECTIVE: Associate statewide trauma system development with a change in the percentage of injured patients initially hospitalized at Levels I and II categorized trauma hospitals and a change in the length of stay (LOS) prior to arrival at a Level I or II hospital (PRE-LOS) and total LOS (T-LOS) for post-admission transfer patients. METHODS: A retrospective analysis was performed using a hospital discharge database of 235,395 discharges with codes for acute injury managed at 74 acute care hospitals in Oregon State from 1983 to 1991. Primary outcome measures were admission site and transfer patient PRE-LOS and T-LOS. Predicator variables included category of initial hospital admission site, injury severity scale (ISS) score, head injury, age, and status of trauma system (pre-system, 1983 to 1987; transitional, 1988 to 1989; and post-system, 1991 to 1992). RESULTS: There was a significant increase in the percentage of initial admissions to hospitals with Level I and II categorization (17.6%, 26.2%, and 27.6% for the three periods of development, respectively; p < 0.00001). The percentage of patients with ISS scores greater than 15 admitted initially to Level I or II hospitals increased from 33.4% to 52.6% and 57.3%; p < 0.00001). Only 1,059 0.57%) of 185,321 patients initially admitted to Level III, Level IV, or noncategorized hospitals were transferred to a Level I or II hospital. Mean PRE-LOS for 1.059 transferred patients showed a significant decrease with system development (2.3, 1.9, and 1.8 days, respectively; p < 0.02). When adjusted for age, ISS score, and head injury effects, mean T-LOS was significantly reduced for the transitional and post-system periods (p < 0.05). CONCLUSIONS: In Oregon, development of a statewide trauma system was associated with increased initial admissions to Level I and II trauma hospitals. For those patients transferred to higher levels of care post- admission, hospital LOSs were decreased with trauma system development.

Adolescent↗
PubMedDate not supplied

Information seeking in primary care: how physicians choose which clinical questions to pursue and which to leave unanswered.

Primary care physicians have many questions about optimal care while they are seeing patients, but they pursue only about 30% of their questions. The authors designed a study to determine the factors that motivate physicians to pursue answers to some of their questions, while leaving the majority of their questions unanswered. They interviewed 49 non-academic primary care physicians during office hours to record clinical questions as they arose in the course of patient care. The physicians then recorded their perceptions of each question with respect to 12 factors expected to motivate information seeking. Two to five days after the interview, each physician was telephoned to determine which questions had been pursued. In a multiple logistic-regression model only two factors were significant predictors of pursuit of new information: the physician's belief that a definitive answer existed, and the urgency of the patient's problem. Other factors, including the difficulty of finding the answer, potential malpractice liability, potential help or harm to the patient, and self-perceived knowledge of the problem, were not significant in the model. Primary care physicians are significantly more likely to pursue answers to their clinical questions when they believe that definitive answers to those questions exist, and when they perceive the patient's problem to be urgent. Medical information systems must be shown to have direct and immediate benefits to solving the problems of patient care if they are to be more widely used by practitioners.

Choice Behavior↗
PubMedDate not supplied

Community-based research--a framework for problem formulation: the case of upper endoscopy for gastroesophageal reflux disease.

OBJECTIVE: To identify clinical hypotheses and information gaps underlying disagreement about the use of upper gastrointestinal endoscopy (EGD) for the diagnosis of gastroesophageal reflux disease (GERD), and to design a registry study to test these hypotheses. DESIGN AND SETTING: Structured group discussions with community-based practicing gastroenterologists. RESULTS: Thirty-three gastroenterologists from 17 sites discussed a set of clinical scenarios concerning the use of EGD in GERD patients with different clinical histories. Clinicians identified patient characteristics and outcome variables missing from the original problem formulation. Using decision tables, the combinations of patient characteristics that provoked disagreement among clinicians were determined. The resulting decision tables specified which characteristics and outcome variables should be measured to test competing clinical theories of when to use EGD in patients with GERD. Subsequently, the clinicians conducted a practice-based study measuring uncertain variables associated with disagreement about the need for EGD in specific clinical situations. CONCLUSION: A structured, but flexible, approach to group discussion may help identify factors that are important in decision making and the hypotheses that should be addressed in resolving variations in practice styles. Technology assessors can use these methods to identify variables underlying clinicians' concerns about the clinical validity of recommendations about practice. This experience with eliciting patient characteristics and uncertain variables underscores the importance of involving practicing clinicians in the process and could be a useful model for problem formulation in guideline development and in community-based research.

Adult↗