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Biomedical subjects

H C Sox

Publications and source records attributed to H C Sox.

At least 19 recordsLinked to original sources
PubMed1991

Costs and health consequences of cholesterol screening for asymptomatic older Americans.

To predict the consequences of cholesterol screening among elderly Americans who do not have symptoms of heart disease, we explore the cost implications of a cholesterol screening program, evaluate evidence linking hypercholesterolemia to coronary heart disease and mortality in the elderly, and describe the likely effects of therapy of hypercholesterolemia. According to our calculations, if all Americans 65 years of age and older adhered to a cholesterol screening program similar to the one proposed by the National Cholesterol Education Program, minimum annual expenditures for screening and treatment would be between $1.6 billion and $16.8 billion, depending on the effectiveness of diet and the cost of the medications used to treat hypercholesterolemia. There is no direct evidence that this program would lessen overall morbidity or extend the lives of elderly Americans.

Aged↗
PubMed1991

Setting the optimal erythrocyte protoporphyrin screening decision threshold for lead poisoning: a decision analytic approach.

Erythrocyte protoporphyrin (EP) was introduced in the 1970s as an inexpensive screening test for lead poisoning. As greater knowledge of lead poisoning has accumulated, the recommended EP level at which further evaluation for lead poisoning should be initiated has been lowered from greater than or equal to 50 micrograms/dL to greater than or equal to 35 micrograms/dL. The purpose of this study was to evaluate the utility of this EP threshold. A receiver operator characteristic curve was constructed to assess the relationship between the true-positive rate and false-positive rate of EP at various decision thresholds. The receiver operator characteristic curve was constructed with data from the second National Health and Nutrition Examination Survey from 1976 to 1980, which included 2673 children 6 years of age or younger who had both blood lead and EP level determinations. Decision analysis was then used to determine the optimal EP decision threshold for detecting a blood lead level greater than or equal to 25 micrograms/dL. The receiver operator characteristic curve demonstrated that EP is a poor predictor of a blood lead level greater than or equal to 25 micrograms/dL. At the currently recommended EP decision threshold of 35 micrograms/dL, the true-positive rates and false-positive rates of EP are 0.23 and 0.04, respectively. As a result of the inadequate performance of EP screening for lead poisoning, when the prevalence of lead poisoning is greater than 8%, there is no EP decision threshold that optimizes the relationship between the cost of screening normal children and the benefit of detecting lead-poisoned children. Erythrocyte protoporphyrin measurement is not sufficiently sensitive to be recommended uniformly as a screening test for lead poisoning.

Child↗
PubMed1990

Screening for hypertension.

PURPOSE: To review the evidence on four questions about screening asymptomatic adults for arterial hypertension: Is hypertension a significant health problem? Is it detectable at an early, presymptomatic stage? Is treatment available and effective? Do the benefits of screening outweigh the costs and risks? DATA IDENTIFICATION AND SELECTION: We did a computerized search of the MEDLARS data base to identify community-based trials of drug therapy for mild hypertension; other relevant citations are included when appropriate. DATA SYNTHESIS: We approached the preliminary questions in our analysis by narrative review and argument. The estimates of therapeutic efficacy are based on previously published meta-analyses. The cost-effectiveness of screening was addressed by formal mathematical modeling of the effect of screening on various U.S. populations. RESULTS OF ANALYSIS: Hypertension is clearly a significant health problem. It can be detected early, and effective treatment is available. Screening asymptomatic adults for hypertension has benefits that compare favorably to the risks and costs involved. According to our estimates, screening is most cost-effective for older adults compared with younger adults and for men compared with women and is highly sensitive to the cost of therapy for mild hypertension. CONCLUSIONS: We recommend hypertension screening for all adults. We also discuss the frequency and setting of screening activities. When a low-cost therapy is used, the cost-effectiveness of screening for hypertension compares favorably with other cardiovascular interventions.

Adult↗
PubMed1990

Using the patient's history to estimate the probability of coronary artery disease: a comparison of primary care and referral practices.

PURPOSE: According to probability theory, the interpretation of new information should depend on the prior probability of disease. We asked if this principle applies to interpreting the history in patients with chest pain. We compared the prevalence of coronary artery disease (CAD) in patients who had similar histories but who came from populations with different disease prevalence. PATIENTS AND METHODS: We studied two high-disease-prevalence populations (patients referred for coronary arteriography) and two low-disease-prevalence populations (patients from primary care practices). We used clinical characteristics of one arteriography population to develop a logistic rule for estimating the probability of coronary artery narrowing. The number of clinical findings determined the logistic score, which was proportional to the prevalence of CAD. RESULTS: The prevalence of CAD was much lower in the primary care population than in the arteriography population, even when patients with similar logistic scores, and thus similar clinical histories, were compared. CONCLUSION: A clinician must take account of the overall prevalence of disease in the clinical setting when using the patient's history to estimate the probability of disease. Failure to observe this caution may lead to errors in test selection and interpretation.

Adult↗
PubMed1990

The role of skin testing for penicillin allergy.

Skin testing for penicillin allergy is an imperfect predictor of severe allergic reactions. We used decision analysis to identify the types of allergy history for which skin testing should alter management. The treatment threshold, the probability of a serious allergic reaction at which point one should switch from penicillin to another antibiotic, depends on the quality of life associated with the clinical outcomes. We measured 12 physicians' attitudes toward the outcomes of treatment with penicillin or vancomycin for Streptococcus viridans endocarditis in patients with a history of penicillin allergy. The clinicians' threshold probabilities ranged from .00010 to .00210 (median, .00013). Given the sensitivity (89% to 96%) and specificity (89% to 96%) of skin testing and our clinicians' median threshold, test results could alter the choice of antibiotic when the probability of a severe allergic reaction is between .00001 and .001. This range corresponds to a weak history of penicillin allergy. Although the decision should be individualized, our study suggests that skin testing is unnecessary when the patient has a convincing history of a severe allergic reaction to penicillin.

Decision Support Techniques↗
PubMed1989

The resting electrocardiogram as a screening test. A clinical analysis.

PURPOSE: To review the evidence that a resting electrocardiogram (ECG) predicts cardiac disease in healthy persons and to discuss the role of this test in screening for coronary artery disease. DATA IDENTIFICATION: A manual search of the English-language literature using Index Medicus (1970-1988) and a bibliographic review of identified articles. STUDY SELECTION: We found 40 articles that described long-term survival of healthy individuals who either had had an abnormal finding on a resting ECG or had not had an abnormal finding. DATA EXTRACTION: We pooled the pertinent studies and calculated the relative risk for coronary artery disease if an ECG finding was present and the 95% confidence limits (CI) on the relative risk. RESULTS OF ANALYSIS: One reason for doing a screening SCG is to detect disease whose effects can be prevented by early treatment. In population studies of healthy middle-aged men, frequent ventricular premature beats, left axis deviation, left ventricular hypertrophy (ECG-LVH), and changes indicative of myocardial ischemia are all associated with a small but statistically significant increase in the risk of dying from coronary artery disease. There is no evidence that early detection of these findings leads to a clinical intervention that improves health outcomes. A screening ECG can also serve as a "baseline" tracing. Two studies have shown that the baseline tracing has little effect on decision making in the emergency room. CONCLUSION: The evidence does not support doing a screening ECG in men without evidence of cardiac disease or cardiovascular risk factors.

Arrhythmias, Cardiac↗
PubMed1989

Screening asymptomatic adults for cardiac risk factors: the serum cholesterol level.

From our review of the epidemiologic and clinical literature, we have developed recommendations for using the serum cholesterol test as a component of strategies to prevent coronary heart disease in asymptomatic adults. Total cholesterol, high-density lipoprotein, and low-density lipoprotein levels are risk factors for coronary disease and early mortality in middle-aged men. Weaker evidence suggests that hypercholesterolemia increases the risk for coronary disease in women or elderly men, or that hypertriglyceridemia increases the risk in men or women. A reduction in cholesterol levels lowers the incidence of and the mortality from coronary disease in asymptomatic, hypercholesterolemic, middle-aged men, but has not been shown to reduce overall mortality. The efficacy of treatment in women and elderly persons has not been studied. Screening and treatment plans should be individualized; a 5-year period between tests is adequate for asymptomatic, low-risk men, whereas more frequent testing is appropriate for high-risk men. Screening is optional for women and elderly persons.

Adult↗
PubMed1989

The role of exercise testing in screening for coronary artery disease.

PURPOSE: To predict the effects of using exercise testing to screen healthy persons for coronary artery disease. DATA IDENTIFICATION: The publications of the Coronary Artery Surgery Study were the principal sources of data for the cost-effectiveness analysis; we also used data from the Veterans Administration Cooperative Study of stable angina and the publications of the European Coronary Surgery Study Group. STUDY SELECTION: We used studies that provided the data that our decision model required--life expectancy and probabilities of outcomes in persons who have or do not have coronary artery disease. DATA EXTRACTION: We did not use a structured method for abstracting data. We tested the susceptibility of our conclusions to poor quality of data by substituting a wide range of values for a variable in the decision model, and by calculating life expectancy and costs if screening was used routinely or not used. RESULTS OF DATA SYNTHESIS: We assumed that persons with an abnormal exercise test would have arteriography and that persons with severe coronary artery disease would have bypass surgery. When there were no suitable published data for the model, we made assumptions that favored screening. The model predicts that screening would increase the life expectancy of 60-year-old men at average risk by at most 12 days. Sixty-year-old men with no risk factors for coronary artery disease would derive less benefit, as would women and younger men. CONCLUSIONS: The effect of exercise testing is too small to justify doing this procedure routinely in healthy persons. If coronary bypass surgery is found to prolong life in asymptomatic persons as much as it does in angina pectoris, screening older men with risk factors for coronary artery disease may prove to be worthwhile.

Coronary Disease↗
PubMed1989

Medical evaluation of psychiatric patients. I. Results in a state mental health system.

Thorough medical evaluation of 529 patients drawn from eight program categories in California's public mental health system revealed active, important physical disease in 200 patients who had 291 diseases. Fourteen percent of the patients had diseases known to themselves but not to the mental health system, and 12% of the patients had diseases newly detected by the study team. We estimate that of the more than 300,000 patients treated in the California public mental health system in fiscal year 1983 to 1984, 45% had an active, important physical disease. The mental health system had recognized only 47% of study patients' physical diseases, including 32 of 38 diseases causing a mental disorder and 23 of 51 diseases exacerbating a mental disorder. Patients treated in public sector mental health facilities should receive careful medical evaluations.

Adult↗
PubMed1989

A medical algorithm for detecting physical disease in psychiatric patients.

An algorithm for screening psychiatric patients for physical disease was empirically derived from a comprehensive assessment of 509 patients in California's mental health system. The first 343 patients were used to develop the algorithm, and the remaining 166 were used as a test group. Calculations were made for several versions of the algorithm, and the data were compared with the diagnoses listed in the patients' admission mental health record. The algorithmic procedure was more accurate and more cost-effective than the medical evaluation procedures used by the state mental health system. When applied to the test group, the algorithm detected up to 90 percent of patients who had an active, important physical disease at a cost of $156 per patient. The mental health system had detected 58 percent of test-group patients with a disease at a cost of $230 per patient.

Algorithms↗