Biomedical subjects
Publications and source records attributed to B Freedman.
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In contrast to attempts that have been made to measure the clarity of reporting of the methods of clinical trials in journal articles, we report here an attempt to measure the accuracy of methods reporting. We focus in this article on eligibility criteria as a test case for the reporting of clinical trial methods. We examined the reporting of eligibility criteria in the protocol, methods paper (if applicable), journal article, and Clinical Alert for articles appearing in print between January 1988 and September 1994 for which a Clinical Alert had been issued. Eligibility criteria were further classified into five categories in order to examine the content of information loss, if any. On average, 82% of protocol eligibility criteria were reported in methods papers. Journal articles and Clinical Alerts fared somewhat worse: 63% of criteria were reported in journal articles, 19% in Clinical Alerts. In all three categories of medical communication, the reporting of criteria that defined the study disease tended to be complete; reporting of criteria relating to trial precision, patient safety, legal and ethical concerns, and administrative considerations, was not complete. We found that criteria for clinical trial eligibility are frequently under-reported in medical communications. Moreover, some of the criteria omitted are of considerable clinical importance. We suggest that in the design phase of clinical trials, proposed eligibility criteria be scrutinized closely. Those criteria that survive this scrutiny and that have clinical import must be reported upon fully and accurately when communicating trial results.
Research review boards, established to protect the rights and welfare of human research subjects, have to ensure that conflicts of interest do not interfere with the ethical conduct of medical research. Private, commercial review boards, which increasingly review research protocols, are themselves affected by a structural conflict of interest. Within the regulatory setting, procedural conflict-of-interest rules are essential because of the absence of clear substantive rules in research review and the reliance on the fairness and good judgment of institutional review board members. Current guidelines and regulations lack adequate conflict-of-interest rules and provide insufficient details on the substantive rules. Because commercial review boards are similar to administrative courts and tribunals, rules of administrative law on bias are applied to determine when a conflict of interest jeopardizes the purposes of research review; administrative law has always judged financial conflicts of interest severely. The structure of private review tends to breach a core principle of administrative law and procedural justice. Reform of the research review system will reinforce public trust in the process.
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The firing reliability and precision of an isopotential membrane patch consisting of a realistically large number of ion channels is investigated using a stochastic Hodgkin-Huxley (HH) model. In sharp contrast to the deterministic HH model, the biophysically inspired stochastic model reproduces qualitatively the different reliability and precision characteristics of spike firing in response to DC and fluctuating current input in neocortical neurons, as reported by Mainen & Sejnowski (1995). For DC inputs, spike timing is highly unreliable; the reliability and precision are significantly increased for fluctuating current input. This behavior is critically determined by the relatively small number of excitable channels that are opened near threshold for spike firing rather than by the total number of channels that exist in the membrane patch. Channel fluctuations, together with the inherent bistability in the HH equations, give rise to three additional experimentally observed phenomena: subthreshold oscillations in the membrane voltage for DC input, "spontaneous" spikes for subthreshold inputs, and "missing" spikes for suprathreshold inputs. We suggest that the noise inherent in the operation of ion channels enables neurons to act as "smart" encoders. Slowly varying, uncorrelated inputs are coded with low reliability and accuracy and, hence, the information about such inputs is encoded almost exclusively by the spike rate. On the other hand, correlated presynaptic activity produces sharp fluctuations in the input to the postsynaptic cell, which are then encoded with high reliability and accuracy. In this case, information about the input exists in the exact timing of the spikes. We conclude that channel stochasticity should be considered in realistic models of neurons.
We studied changes in eligibility criteria--the largest impediment to patient accrual--in two samples of clinical trials. Trials from the NSABP (National Surgical Adjuvant Breast and Bowel Program) and POG (Pediatric Oncology Group) were analyzed. After eliminating duplications, the criteria in each protocol were enumerated and classified according to a novel schema. NSABP trials contained significantly more criteria than POG trials, and added precision criteria (making study populations homogeneous) at a faster rate than POG studies. The difference between NSABP studies (explanatory trials) and POG studies (pragmatic trials) suggest that large numbers of eligibility criteria are not necessary for quality studies. We recommend that: (1) the inclusion/exclusion criteria distinction be abandoned; (2) eligibility criteria be explicitly justified; (3) the need for each criterion be assessed when new trials are planned; (4) criteria in phase III trials restricting patient accrual be minimized; and (5) further research be done to assess the impact of criteria on generalizability.
OBJECTIVE: To investigate whether eligibility criteria that exclude the elderly, persons with psychiatric disease, and persons with substance abuse problems from participation in randomized controlled trials (RCTs) are subjective and hence a source of variability in enrolment decisions and investigator uncertainty. DESIGN: Survey questionnaire. PARTICIPANTS: Cancer investigators from the United States and Canada. INTERVENTIONS: Investigators were presented with clinical vignettes from 3 patient categories--eligible, ineligible and uncertain--for each of 5 eligibility criteria--3 subjective and 2 objective--and were asked whether they would enrol the patient in a trial and how sure they were of this decision. Demographic characteristics of the investigators were also collected. OUTCOME MEASURES: The difference in enrolment decisions between subjective and objective criteria, and the difference in the certainty associated with these decisions. RESULTS: Of 365 questionnaires sent out, 224 usable ones were returned. Compared with the objective criteria, the subjective criteria were associated with more variable enrolment decisions (p = 0.07 for the "eligible" scenario and p = 0.0001 for the "ineligible" and "uncertain" scenarios), and investigators were less sure about the decisions they made (p = 0.0001 for all scenarios). Demographic characteristics of the investigators failed to explain the observed differences. CONCLUSIONS: Subjective eligibility criteria may interfere with the conduct and interpretation of RCTs and, therefore, their use ought to be justified explicitly in the study protocol. RCT designers, funding agencies and research ethics boards have an important role in reviewing eligibility criteria for their necessity.
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OBJECTIVE: Pilot study to characterize treatment differences between patients treated in clinical trials and those treated in a clinical setting. Previous studies have shown higher survival rates for participants in trials of cancer therapy. This difference is observed even after rates are adjusted for important covariates such as age and stage of disease. DESIGN: Retrospective chart review. SETTING: Oncology outpatient department in a tertiary care hospital. PATIENTS: Ninety women 18 to 70 years of age with early-stage breast cancer who were diagnosed in 1990. Fifty-one of the women were treated through clinical trials and 39 were treated outside of clinical trials. OUTCOME MEASURES: Number of blood tests, telephone calls, clinic visits and imaging procedures as well as intensity of chemotherapy and use of radiation therapy. The age of the patient and the stage of disease were important covariates. RESULTS: After the analysis was controlled for patient age and stage of disease, patients treated through a clinical trial were more likely to receive standard-dose chemotherapy (p = 0.020, 95% confidence interval 1.20 to 200.73) and more frequent blood tests (p < 0.001, 95% confidence interval 1.02 to 1.13) than other patients treated in the clinic. CONCLUSIONS: Our results provide a plausible mechanism for the observed survival advantage for participants in clinical trials in oncology. Further study is called for. If these results are confirmed, they have important implications for informed consent to participate in clinical trials and for clinical practice.
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PURPOSE: To develop a curriculum in ethics in family practice by studying which ethical issues physicians believe to be important based on frequency of encounter, difficulty in managing the problem, and helpfulness of discussion; to examine whether there are any important differences between faculty and residents and between genders; and to determine the preferred format(s) for teaching these issues. METHOD: Between November 1991 and June 1992 a total of 475 questionnaires were mailed to all the family practice residents (first- and second-year), graduates in their first two years of practice, and the physician faculty of the Department of Family Medicine at the McGill University Faculty of Medicine. Overall, 319 usable questionnaires were returned, for a final response rate of 67%. The questionnaire asked respondents to evaluate 14 ethical dilemmas in order to determine the importance of teaching specific ethical issues as well as to determine the preferred format for teaching. Chi-square tests, analyses of variance, and Student's t-tests were used to test the significance of differences in responses. RESULTS: No consistent pattern of interrelationship was found among frequency of encounter and difficulty and helpfulness of discussion for most items. Overall, there was little difference in how faculty and residents, men and women, perceived the importance of these ethical issues. Women reported encountering ethical issues less frequently than men [F (14,285) = 1.82, p < .04], while at the same time finding them somewhat more difficult and more deserving of discussion. Small-group, case-oriented discussion appears to have been the favored teaching format regardless of the ethical dilemma. CONCLUSION: It is difficult to narrow down the content to be included in a curriculum in ethics in family practice. Frequency of encounter, difficulty in management, and helpfulness of discussion can all be argued to be important factors for consideration; they should all be considered separately or in combination for each teaching situation if time restrictions force a choice between topics.
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In summary, the usual elements of a typical health care ethics consultation note might reasonably accommodate the needs and expectations of relevant parties, and would therefore include: 1. identification of the relevant ethical issues, questions, or dilemmas; 2. reference to any relevant facts--medical, nursing, social, psychological, spiritual, legal, political, etc.; 3. a prioritized list of recommendations to improve coordinated care; 4. a clear and concise articulation of relevant arguments, wtih specific reference to the list of recommendations as well as to the institution's overall ethos; 5. a contextual statement, identifying the perceived degree of consensus or support for the recommendations and conclusions, as well as any inherent agendas.