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Biomedical subjects

A R Feinstein

Publications and source records attributed to A R Feinstein.

At least 37 records · Page 2Linked to original sources
PubMed1999

Antecedent therapy versus detection bias as causes of neoplastic multimorbidity.

Neoplastic multimorbidity occurs when a patient is found to have a second primary cancer after the occurrence of a first. The phenomenon may be the result of aging, chance, or other specific causes, but in recent years, the radio- or chemotherapy administered for the first cancer has regularly been suspected as a possible cause of the second. A commonly disregarded alternative explanation, however, is that the second cancers were clinically "silent" discoveries found because of increased diagnostic detection procedures in patients known to have a first cancer. Such patients are more likely to receive intensive surveillance and technologic testing than the general population often used as a control group. In 43 recent reports of neoplastic multimorbidity, however, only five mentioned the problem of detection bias, and only one tried to eliminate it by using a suitable analytic comparison. Unless adequate analytic precautions are taken, antineoplastic therapy may be falsely accused of being carcinogenic.

Bias↗
PubMed1999

The impact of ethnicity, family income, and parental education on children's health and use of health services.

OBJECTIVES: This study characterized ethnic disparities for children in demographics, health status, and use of services; explored whether ethnic subgroups (Puerto Rican, Cuban, and Mexican) have additional distinctive differences; and determined whether disparities are explained by differences in family income and parental education. METHODS: Bivariate and multivariate analyses of data on 99,268 children from the 1989-91 National Health Interview Surveys were conducted. RESULTS: Native American, Black, and Hispanic children are poorest (35%, 41% below poverty level vs 10% of Whites), least healthy (66%-74% in excellent or very good health vs 85% of Whites), and have the least well educated parents. Compared with Whites, non-White children average fewer doctor visits and are more likely to have excessive intervals between visits. Hispanic subgroup differences in demographics, health, and use of services equal or surpass differences among major ethnic groups. In multivariate analyses, almost all ethnic group disparities persisted after adjustment for family income, parental education, and other relevant covariates. CONCLUSIONS: Major ethnic groups and subgroups of children differ strikingly in demographics, health, and use of services; subgroup differences are easily overlooked; and most disparities persist even after adjustment for family income and parental education.

Adolescent↗
PubMed1998

Prognostic staging system for recurrent, persistent, and second primary cancers of the oral cavity and oropharynx.

OBJECTIVE: To develop a practical staging system for predicting mortality of patients with recurrent squamous cell tumors of the oral cavity and oropharyngeal mucosa. DESIGN AND SETTING: An inception cohort at an academic medical center. PATIENTS: A total of 308 patients who had evidence of recurrent, persistent, or second primary tumors of the oral cavity and oropharynx between January 1, 1980, and December 31, 1991, of whom 162 (52.6%) met inclusion criteria. MAIN OUTCOME MEASURE: One-year mortality. RESULTS: The median survival time was 10 months. In bivariate analysis, the TNM stage of the recurrent tumor, invasion of pharyngeal constrictors and the floor-of-mouth muscles, weight loss, local and systemic symptoms, and eating function had significant effects on mortality. Multivariable analysis (done by conjunctive consolidation and Cox regression) identified constrictor invasion, the TNM stage of the recurrence, and weight loss as having a substantial effect on mortality. A composite 4-stage system using these 3 variables demarcated 1-year survival rates of 88.2% (30/34), 71.9% (23/32), 32.6% (16/49), and 4.2% (2/47). CONCLUSIONS: The TNM status of recurrent tumors predicts mortality, but constrictor muscle invasion and weight loss also have major prognostic importance. The consolidation of these variables into a composite staging system successfully stratifies patients with widely divergent mortality rates. Improved staging of recurrent head and neck tumors can lead to more effective decisions about the comparisons and merits of additional treatment.

Aged↗
PubMed1998

Academic calculations versus clinical judgments: practicing physicians' use of quantitative measures of test accuracy.

PURPOSE: To determine how often practicing physicians use the customarily recommended quantitative methods that include sensitivity, specificity, and likelihood ratio indexes; receiver operator characteristic (ROC) curves; and Bayesian diagnostic calculations. PARTICIPANTS AND METHODS: A random sample of 300 practicing physicians (stratified by specialty to include family physicians, general internists, general surgeons, pediatricians, obstetrician/gynecologists, and internal medicine subspecialists) were briefly interviewed in a telephone survey. They were asked about the frequency with which they used the formal methods, the reasons for non-use, and if they employed alternative strategies when appraising tests' diagnostic accuracy. RESULTS: Of the 300 surveyed physicians, 8 (3%) used the recommended formal Bayesian calculations, 3 used ROC curves, and 2 used likelihood ratios. The main reasons cited for non-use included impracticality of the Bayesian method (74%), and nonfamiliarity with ROC curves and likelihood ratios (97%). Of the 174 physicians who said they used sensitivity and specificity indexes, 165 (95%) did not do so in the recommended formal manner. Instead, the physicians directly estimated tests' diagnostic accuracy by determining how often the test results were correct in groups of patients later found to have, or to be free of, the selected disease. CONCLUSIONS: The results indicate that most practicing physicians do not use the formal recommended quantitative methods to appraise tests' diagnostic accuracy, and instead report using an alternative direct approach. Although additional training might make physicians use the formal methods more often, the physicians' direct method merits further evaluation as a potentially pragmatic tool for the determination of tests' diagnostic accuracy in clinical practice.

Adult↗
PubMed1998

P-values and confidence intervals: two sides of the same unsatisfactory coin.

For both P-values and confidence intervals, an alpha level is chosen to set limits of acceptable probability for the role of chance in the observed distinctions. The level of alpha is used either for direct comparison with a single P-value, or for determining the extent of a confidence interval. "Statistical significance" is proclaimed if the calculations yield a P-value that is below alpha, or a 1-alpha confidence interval whose range excludes the null result of "no difference." Both the P-value and confidence-interval methods are essentially reciprocal, since they use the same principles of probabilistic calculation; and both can yield distorted or misleading results if the data do not adequately conform to the underlying mathematical requirements. The major scientific disadvantage of both methods is that their "significance" is merely an inference derived from principles of mathematical probability, not an evaluation of substantive importance for the "big" or "small" magnitude of the observed distinction. The latter evaluation has not received adequate attention during the emphasis on probabilistic decisions; and careful principles have not been developed either for the substantive reasoning or for setting appropriate boundaries for "big" or "small." After a century of "significance" inferred exclusively from probabilities, a basic scientific challenge is to develop methods for deciding what is substantively impressive or trivial.

Confidence Intervals↗
PubMed1998

The quest for "power": contradictory hypotheses and inflated sample sizes.

To have the "power" of avoiding undersized clinical trials, the customary statistical strategy used in the past few decades is aimed at rejecting both a null stochastic hypothesis and a contradictory alternative hypothesis. This approach gives a trial the "power" to confirm the "insignificance" of differences much smaller than the large value of delta desired in trials done to show efficacy. In many instances, however, a prime problem is that the current "double-significance" approach produces sample sizes 2-3 times larger than needed for stochastic confirmation of large differences (> or =delta). The inflated sample sizes and consequent problems can be avoided if a realistic value for delta is chosen and maintained thereafter, and if an adequate "capacity" is calculated for "single significance."

Bias↗
PubMed1997

A clinimetric approach to the components of the patient-physician relationship.

Although patient-physician relationships have been expressed with diverse concepts and models, we have formulated a clinimetric classification derived from several years of observation and discussions at weekly house-staff conferences devoted to "difficult" patients. The observed phenomena are classified into the following components: (1) background factors intrinsic to patient and physician before they meet, (2) individual anticipations and hopes for what may happen, (3) extrinsic features of the setting, (4) individual reactions during the encounter, and (5) the consequences thereafter. These interacting components are usually too complex for characterizations based on single models for the relationship or single titles (such as "hateful" or "noncompliant") for the patient. The components can serve as a "review of systems" for identifying manifestations, sources, and solutions to such common problems as discordant hopes, the physician's unawareness of the patient's pertinent extramedical status, psychiatric and mental-status challenges, and cogent factors in chronic illness.

Attitude to Death↗
PubMed1997

The impact of clinical history on mammographic interpretations.

OBJECTIVE: To determine whether mammographic interpretations are biased by the patient's clinical history. DESIGN: On 2 occasions, separated by a 5-month wash-out period, 10 radiologists read mammograms for the same 100 women, randomly divided into 2 groups of 50. For 1 group, the clinical history was supplied for the first reading and omitted (except for age) for the second reading. This sequence was reversed in the other group. In addition, 5 cases were shown a third time with a deliberately leading sham history. PATIENTS: Selected with stratified random sampling from 3 categories of diagnostic findings (64 had mammographic abnormalities) and from the definitive designation of breast cancer or no breast cancer (18 had breast cancer). MAIN OUTCOME MEASURES: Radiologists' diagnostic accuracy and directional changes in interpretations and recommendations between the 2 readings. RESULTS: The direction suggested by the history led to small but consistent changes in the interpretations. Overall diagnostic accuracy was not altered, but recommendations were affected for appropriate further diagnostic workup: an alerting history (eg, breast symptoms or family history of breast cancer) increased the number of workups recommended in patients without cancer (P=.01); and a nonalerting history led to fewer recommended workups in the cancer patients (P=.02). The direction of the sham histories led an average of 4 of the 10 radiologists to change previous diagnoses and an average of 1 radiologist to change a previous biopsy recommendation. CONCLUSIONS: Knowledge of the clinical history may alter a radiologist's level of diagnostic suspicion without improving performance in either diagnosis or management recommendations.

Adult↗
PubMed1997

Asking patients what they like: overlooked attributes of patient satisfaction with primary care.

PURPOSE: Ask patients to describe important attributes of their primary health care; and use the responses to develop a taxonomy for classifying patient satisfaction. DESIGN: Open-ended questions were administered to patients immediately after a clinic visit. SETTING: Primary care clinics at an academically affiliated Veterans Affairs Medical Center in New England. PATIENTS: Two hundred two of 204 randomly selected English-speaking patients who agreed (and were able) to participate. INTERVENTIONS: Clinimetric methods were used to obtain responses to three open-ended questions about what patients liked, disliked, and would like to see changed about their care. These "raw" descriptions were then combined into pertinent groups and arranged as a taxonomy of patient satisfaction. RESULTS: The taxonomy was divided into five main axes referring to physician staff, nonphysician staff, attributes of the clinic, related services, and the institution. The axes contained a total of 34 items related to patient satisfaction. The items have demonstrable face validity, and are likely to be "transparently" sensible to clinicians and policy makers, but many of the items-such as problems with parking-were not included in either of two existing psychometric instruments used to measure patient satisfaction in the same clinics. CONCLUSIONS: The clinimetric strategy leads to a simple, clinically relevant, and easily understood assessment of patient satisfaction with health care services. The assessment can be done with three simple questions; and the responses can be catalogued, when desired, in a suitable taxonomy.

Adult↗
PubMed1997

Problems in the "evidence" of "evidence-based medicine".

The proposed practice of "evidence-based medicine," which calls for careful clinical judgment in evaluating the "best available evidence," should be differentiated from the special collection of data regarded as suitable evidence. Although the proposed practice does not seem new, the new collection of "best available" information has major constraints for the care of individual patients. Derived almost exclusively from randomized trials and meta-analyses, the data do not include many types of treatments or patients seen in clinical practice; and the results show comparative efficacy of treatment for an "average" randomized patient, not for pertinent subgroups formed by such cogent clinical features as severity of symptoms, illness, co-morbidity, and other clinical nuances. The intention-to-treat analyses do not reflect important post-randomization events leading to altered treatment; and the results seldom provide suitable background data when therapy is given prophylactically rather than remedially, or when therapeutic advantages are equivocal. Randomized trial information is also seldom available for issues in etiology, diagnosis, and prognosis, and for clinical decisions that depend on pathophysiologic changes, psychosocial factors and support, personal preferences of patients, and strategies for giving comfort and reassurance. The laudable goal of making clinical decisions based on evidence can be impaired by the restricted quality and scope of what is collected as "best available evidence." The authoritative aura given to the collection, however, may lead to major abuses that produce inappropriate guidelines or doctrinaire dogmas for clinical practice.

Decision Making↗
PubMed1997

Clinical utility of endoscopic retrograde cholangiopancreatography.

BACKGROUND: ERCP is a frequently performed procedure, but its necessity for diagnosis and ability to change management plans are unclear in many cases. METHODS: We prospectively evaluated diagnosis, certainty of diagnosis, and management recommendations, both before and after ERCP, as well as therapeutic maneuvers performed during ERCP, in unselected patients undergoing this procedure. RESULTS: ERCP procedures (1341) were studied at a university hospital, an ERCP referral center, and two community hospitals. Among patients undergoing first-time ERCP, the preceding clinical diagnosis was correct for 64% of those predicted to have bile duct stones, 86% to 89% of those given other biliary diagnoses, and 88% predicted to be normal. In 35% of cases, diagnostic confidence improved substantially after ERCP. Endoscopic therapy was successfully completed in 51%. After ERCP, plans for other invasive procedures changed in 82%: percutaneous biliary studies and open surgical procedures were recommended less often and laparoscopic cholecystectomy more often. Endoscopic therapy and overall clinical utility were most common in patients with cholangitis, jaundice, or bile leaks. CONCLUSIONS: ERCP is particularly helpful for diagnosis of bile duct stones but is less likely to change other diagnoses. The endoscopic therapy commonly carried out during ERCP often changes the treatment plan, leading to fewer surgical and percutaneous interventions in general, but more laparoscopic cholecystectomies.

Bile Duct Diseases↗