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Biomedical subjects

A R Feinstein

Publications and source records attributed to A R Feinstein.

At least 145 records · Page 8Linked to original sources
PubMed1988

A box-graph method for illustrating relative-size relationships in a 2 x 2 table.

The proportional relationships of the four numbers in a 2 x 2 table can be displayed using two types of box graphs. In one approach, a 'unitary square' is first divided according to the denominator proportions of the two groups formed in a cohort or case-control study, and then re-divided according to the numerator proportions in each group. In the second method, the numbers are arranged as four squares, proportionately sized according to the square root of each number, and contiguously adjacent to a central reference point. The methods offer a pictorial format for showing contingency counts in a manner analogous to the graphs used for other forms of data.

Data Interpretation, Statistical↗
PubMed1988

A collection of 56 topics with contradictory results in case-control research.

This research was done to learn more about the frequency and characteristics of conflicting research in case-control studies. In a survey of the epidemiological and medical literature, we found 56 topics in which the results of a case-control study were in conflict with the results from other studies of the same relationship. Cancer was the associated disease for 30 of the controversial topics. We suggest that much of the disagreement may occur because a set of rigorous scientific principles has not yet been accepted to guide the design or interpretation of case-control research. Consequently, the investigator's 'judgement' is the main precaution against scientific hazards and distortions in the validity of evidence. To correct this deficiency, we propose using the principles of an experimental trial to develop the scientific standards for case-control research.

Cohort Studies↗
PubMed1988

Detection bias in the diagnostic pursuit of lung cancer.

Autopsy studies have shown that lung cancer is often not detected during life and that a correct antemortem diagnosis is made preferentially in patients with pulmonary symptoms, in smokers, and in men. The current research was done as a case-control study to determine whether the autopsy suggestions of detection bias in diagnostic pursuit of lung cancer were confirmed by the way that sputum Papanicolaou smears (Pap smears) were ordered in an inpatient setting. The cases were 385 hospitalized patients in whom sputum Pap tests had been newly performed from October 1977 to September 1980. Each case was matched by age, admission date, and admission diagnosis to a control patient who had not received a Pap test. Excluded from the study were patients in whom sputum Pap tests were obligatory (e.g., those with manifestations of hemoptysis) or unnecessary (e.g., those with a previous diagnosis of lung cancer or multiple previous sputum Pap tests). Demographic data, amount and duration of cigarette smoking, and details of clinical manifestations were extracted from the patients' medical records by research assistants blind to the study hypothesis. Compared with controls, the cases had distinctive elevations in odds ratios for chronic cough, recent cough, male sex, and cigarette smoking, which also showed a distinctive dose-response relation. In multivariate analyses, all four of these "risk factors" for selective ordering of a sputum Pap smear remained independently highly significant. In the extreme category, men who smoked and coughed were 22 times more likely to have a sputum Pap test ordered than were nonsmoking women who did not cough. Clinically, the results suggest that women and nonsmokers may be deprived of appropriate diagnosis and therapy unless a diagnostic workup for lung cancer is guided mainly by radiographic findings and presenting manifestations. Statistically, detection bias has probably led to an excessively elevated magnitude for the cigarette smoking-lung cancer association and to a falsely low estimate of incidence rates in women.

Adult↗
PubMed1988

A review of systems for the personal aspects of patient care.

Because patients are appropriate judges of the personal aspects of the care received from physicians, the authors conducted lengthy interviews with 50 randomly chosen medical inpatients. They were asked to describe, in an open-ended but semistructured fashion, their favorable and unfavorable impressions and reactions to the personal aspects of care rendered by their physicians. From the specific comments made by the patients in these interviews, we constructed a detailed taxonomy of desired physician attitudes and behaviors. The taxonomy can be used in a manner analogous to a Review of Systems for teaching students and practitioners the elements of personal care and also can be applied for research in patient-physician communication.

Adult↗
PubMed1987

The 'epidemiologic necropsy'. Unexpected detections, demographic selections, and changing rates of lung cancer.

When rising rates of occurrence are reported for a particular disease, clinicians often cannot determine whether the disease has increased in actual occurrence or in the improved detection provided by better diagnostic technology and expanded access to medical care. The epidemiologic use of necropsy data, which might help answer these questions, has been inhibited by fears of bias in demographic and clinical selection of patients for necropsy. The demographic problem can be managed by suitable adjustment and standardization of the disease rates found at necropsy, and the clinical problem can be reduced or avoided by studying the rates with which the disease is found unexpectedly in necropsies performed for other, unrelated clinical reasons. The results, obtained in population groups "screened" via necropsy, can suggest the magnitude of the "undetected reservoir" that coexists and supplements the rates of reported occurrence for a disease. In a study of necropsies at Yale-New Haven (Conn) Hospital from 1972 to 1981, the necropsy detection rates for lung cancer were slightly higher for women than for men, and were substantially higher for both genders than the customarily reported rates in the general population. The results suggest that the reported rates may continue to rise in both genders until they become essentially equal at a size approximating that of the currently undetected reservoir. The "epidemiologic necropsy" offers a potentially valuable method to help distinguish the true occurrence rates of disease from the changes attributable to improved diagnostic detection with modern technology.

Adult↗
PubMed1987

Incidence, prevalence, and evidence. Scientific problems in epidemiologic statistics for the occurrence of cancer.

Major changes in policy for health, nutrition, and industrial safety have been proposed because of the "epidemic of apprehension" produced by statistics for the occurrence rates of cancer. The statistical information, however, contains gross violations of epidemiologic principles and scientific standards for credible evidence. The calculations often depend on an improper linkage of numerators and denominators; and the calculated rates, assembled from reports of overtly detected cases of cancer, represent neither incidence nor prevalence. Many of the secular or regional changes in rates are due to corresponding changes in the availability and dissemination of diagnostic technology, but the technologic changes have not been adequately evaluated or investigated. Improvements will require drastically altered approaches to the use of death certificates, tumor registries, and clues from necropsy data.

Cross-Sectional Studies↗
PubMed1987

Quantitative ambiguities in matched versus unmatched analyses of the 2x2 table for a case-control study.

When controls are individually matched to the cases in a case-control study, the subsequent data can be analysed in a matched or unmatched format. If done with careful attention to clinical variables that can produce important bias or confounding, the matching would have a scientific basis that warrants preservation of a matched analysis. If done, however, in the more common manner, as an act of demographic convenience, the matching is not based on a cogent 'correlation'; and an unmatched analysis may be preferred because it uses all the data and it is easier to understand. Regardless of the merits of the arguments, investigators can choose (and can often justify) either a matched or unmatched analysis. If the matched table is structured in the customary format of (a b/c d), the results for the odds ratio and chi-square test in the matched and unmatched analyses will be relatively similar if ad congruent to bc, but be strikingly disparate if ad is substantially higher or lower than bc. The same distinction can be noted by comparing a (or any value observed in the four cells) with the corresponding value that would be expected for that cell as calculated from the marginal totals. If the observed and expected values sharply disagree, the values of the odds ratio and chi-square will sharply disagree in the matched and unmatched formats. To avoid invidious choices when disparate results emerge from the matched and unmatched methods, investigators can routinely apply and routinely report what is found with both methods. Readers can then see both sets of results and can take their choice.

Epidemiologic Methods↗
PubMed1987

Coding ordinal independent variables in multiple regression analyses.

The authors present a coding scheme for ordinal independent variables which may be used in various forms of regression analysis. The scheme is useful in dose-response analyses, when the objective is to identify contrasts in the dependent (or response) variable between successive levels of the independent variable, or to identify critical threshold values of the independent variables at which significant changes occur in the response. An example is given of evaluating the survival of lung cancer patients according to their stage of symptomatology. The authors discuss the interpretation of the regression coefficients when this coding scheme is used with linear regression, logistic regression, or in the proportional hazards regression model.

Humans↗
PubMed1987

A reappraisal of the United Kingdom epidemic of fatal asthma. Can general mortality data implicate a therapeutic agent?

The 1960s epidemic of asthma deaths that affected young persons in England and Wales, as well as in other countries, was attributed to the effect of newly available pressurized aerosols containing sympathomimetic bronchodilators. The subsequent decision to ban the nonprescription sale of these agents in the United Kingdom represented a unique use of national and international mortality data. The application of such data for decisions about therapeutic agents has implications for the current rise of asthma deaths in New Zealand, for the recent United States regulatory action regarding the nonprescription sale of aerosolized bronchodilators, and for the appraisal of adverse reactions to other pharmaceutical substances. This article is concerned with the quality of the scientific evidence used to implicate bronchodilators in the 1960s epidemic, and also with the strengths and weaknesses of the ecologic studies on which the implication depended. After concluding that the causal link between asthma deaths and bronchodilators was not supported by satisfactory scientific evidence, we present new data and an alternative diagnostic-exchange hypothesis that may, in part, help explain the original association.

Adolescent↗