A critique of methodology in studies of anticoagulant therapy for acute myocardial infarction

Do stroke models model stroke?

Stroke is one of the leading causes of death worldwide and the biggest reason for long-term disability. Basic research has formed the modern understanding of stroke pathophysiology, and has revealed important molecular, cellular and systemic mechanisms. However, despite decades of research, most translational stroke trials that aim to introduce basic research findings into clinical treatment strategies - most notably in the field of neuroprotection - have failed. Among other obstacles, poor methodological and statistical standards, negative publication bias, and incomplete preclinical testing have been proposed as 'translational roadblocks'. In this article, we introduce the models commonly used in preclinical stroke research, discuss some of the causes of failed translational success and review potential remedies. We further introduce the concept of modeling 'care' of stroke patients, because current preclinical research models the disorder but does not model care or state-of-the-art clinical testing. Stringent statistical methods and controlled preclinical trials have been suggested to counteract weaknesses in preclinical research. We conclude that preclinical stroke research requires (1) appropriate modeling of the disorder, (2) appropriate modeling of the care of stroke patients and (3) an approach to preclinical testing that is similar to clinical testing, including Phase 3 randomized controlled preclinical trials as necessary additional steps before new therapies enter clinical testing.

Development and evaluation of an instrument for the critical appraisal of randomized controlled trials of natural products

BACKGROUND

The efficacy of natural products (NPs) is being evaluated using randomized controlled trials (RCTs) with increasing frequency, yet a search of the literature did not identify a widely accepted critical appraisal instrument developed specifically for use with NPs. The purpose of this project was to develop and evaluate a critical appraisal instrument that is sufficiently rigorous to be used in evaluating RCTs of conventional medicines, and also has a section specific for use with single entity NPs, including herbs and natural sourced chemicals.

METHODS

Three phases of the project included: 1) using experts and a Delphi process to reach consensus on a list of items essential in describing the identity of an NP; 2) compiling a list of non-NP items important for evaluating the quality of an RCT using systematic review methodology to identify published instruments and then compiling item categories that were part of a validated instrument and/or had empirical evidence to support their inclusion and 3) conducting a field test to compare the new instrument to a published instrument for usefulness in evaluating the quality of 3 RCTs of a NP and in applying results to practice.

RESULTS

Two Delphi rounds resulted in a list of 15 items essential in describing NPs. Seventeen item categories fitting inclusion criteria were identified from published instruments for conventional medicines. The new assessment instrument was assembled based on content of the two lists and the addition of a Reviewer's Conclusion section. The field test of the new instrument showed good criterion validity. Participants found it useful in translating evidence from RCTs to practice.

CONCLUSION

A new instrument for the critical appraisal of RCTs of NPs was developed and tested. The instrument is distinct from other available assessment instruments for RCTs of NPs in its systematic development and validation. The instrument is ready to be used by pharmacy students, health care practitioners and academics and will continue to be refined as required.

Effect of ethics consultations in the intensive care unit

Although evidence-based research is limited, results suggest that ethics consultations are associated with reductions in hospital days and intensive care unit days and in life-sustaining treatments in those patients who ultimately will not survive to discharge. Furthermore, the majority of healthcare providers and patients/surrogates agreed that ethics consultations in the intensive care unit were helpful in addressing treatment conflicts. Ethics consultations also reduce hospital costs without diminishing the quality of care. Hence, ethics consultations seem to be useful in resolving conflicts that may be inappropriately prolonging nonbeneficial or unwanted treatments at the end of life. Further research on whether ethics consultations are beneficial in other settings is needed to establish the optimal scope of this intervention. Also, the benefits described above were achieved by highly skilled and experienced consultants. It is not certain, therefore, how successful other hospitals will be when adopting this intervention.

The (alternative) medicalization of life

The writers in this symposium are drawn together under the topic of medicine — not to discuss any new discovery in the prevention or treatment of disease. Quite the contrary. We are drawn here to consider a phenomenon. We are here to consider whether a collective romantic fantasy called alternative medicine that has seized our society really deserves the acclaim it is receiving. This, for the most part, is what people like us do when we gather in symposia or meetings to discuss alternative medicine. We argue about beliefs and claims, not results. Are the beliefs and claims of this collective romantic fantasy justified by empirical data? Or rather, will the beliefs and claims of this collective romantic fantasy be justified by empirical data because the fantasy is already securely in place in our political and fiscal, medical and educational, structures?

Anticoagulation and the heart

Cardiovascular disease is associated with a heightened risk of thrombosis that can manifest as acute myocardial infarction, cardiac death, and stroke. Similarly, valvular heart disease (which alters blood-flow dynamics) and the insertion of prosthetic materials (which stimulates localized thrombosis on foreign surfaces) are associated with platelet aggregation and thrombin-mediated bioamplification of the coagulation cascade. Physiologic principles and pathobiologic mechanisms determine the preferred means either to prevent or attenuate both thrombosis and subsequent cardiovascular events. Anticoagulant therapy in hospital- and outpatient-based settings has appropriately assumed a central role in the prevention and treatment of thrombotic disorders of the cardiovascular system. Carefully-designed clinical trials will establish safe and effective antithrombotic therapies for wide-scale implementation.

Antiplatelet medications and their indications in preventing and treating coronary thrombosis

Platelets play a pivotal role in the pathophysiology of unstable angina, acute myocardial infarction, and complications following percutaneous coronary intervention. Three classes of platelet-inhibiting drugs, aspirin, thienopyridines and platelet glycoprotein IIb/ IIIa inhibitors, are now commonly used for the prevention and treatment of disorders of coronary artery thrombosis. For the last several decades aspirin has been the sole option for antiplatelet therapy in the treatment and prevention of the manifestations of cardiovascular disease. However, a wider selection of antiplatelet agents, including the thienopyridines (ticlopidine and clopidogrel) and the platelet glycoprotein (GP)IIb/IIIa receptor antagonists, are now available and provide clinicians with the opportunity to potentially improve upon the previous gold standard of aspirin. This review summarizes these drugs and the scientific data that have led to their use in primary and secondary prevention, unstable angina, myocardial infarction, and percutaneous coronary intervention.

Are clinical practice guidelines valid for primary care?

Development of evidence-based clinical practice guidelines has emphasized treatment efficacy under methodologically rigorous conditions; internal validity (i.e., efficacy) has been assessed well. Despite their experimental foundations, guidelines originally were considered physician education tools relevant to singular, idealized encounters. Now, in rushing to generalize, quantify, and regulate quality, guidelines are being applied to whole populations as quality review criteria. Clinical guidelines do not make operational how, or even make clear whether they should be so used. We studied the external validity, the generalizability and measurability for primary care, of a guideline for treatment of systolic heart failure. Patient and clinical factors reducing generalizability were examined. Imprecise definition and reliance on single measures of recommendations were studied as limits to measurability. Patient, physician, organizational, and system factors influenced guideline validity. Attention to myriad invalidity sources undermining implementation and evaluation of efforts to improve quality and outcomes of primary care is critical.

Rating the quality of evidence for clinical practice guidelines

This article describes the system for rating the quality of medical evidence developed and used during creation of the Agency for Health Care Policy and Research-sponsored heart failure guideline. Previous approaches to rating evidence were not designed for use in the setting of clinical practice guidelines. The present system is based on the tenet that flaws in research design are serious to the extent they threaten the validity of the results of studies. A taxonomy of major and minor flaws based on that tenet was developed for randomized controlled trials and for cohort and medical registry studies. The use of the system is described in the context of two difficult clinical issues considered by the Panel: the role of coronary artery revascularization and the use of metoprolol.

Acute myocardial infarction. Then and now

Dramatic changes in the management of acute myocardial infarction (AMI) have occurred in the past decade. While previous management strategies were primarily supportive, current strategies focus on achieving and maintaining patency of the infarct-related artery restoring blood flow to jeopardized myocytes, preserving left ventricular function, and preventing recurrences and complications in addition to promoting healing. Restoration of blood flow can be achieved pharmacologically with thrombolytic agents or mechanically with percutaneous transluminal coronary angioplasty (PTCA). Early use of antiplatelet agents and anticoagulants helps maintain patency of the infarct-related arteries and prevents thromboembolic complications. Administration of beta-blockers and angiotensin enzyme inhibitors are more specific means of conserving myocardium and preserving ventricular function. Additionally, several strategies for preventing arrhythmias such as prophylactic lidocaine use and routine long-term suppression of premature ventricular contractions with antiarrhythmic drugs are no longer routinely advocated. Basically, in the era prior to the eighth decade of this century, the primary direction of the therapeutic strategy for AMI was to reduce the oxygen demands in the infarcted myocardium; whereas in the subsequent years, the emphasis shifts to improvement in oxygen delivery, via thrombolysis, PTCA, and coronary artery bypass graft surgery. These interventional changes, when added to greater sophistication in the use of drugs to reduce oxygen demands, resulted in significant lowering of myocardial mortality.

Long-term anticoagulant treatment after acute myocardial infarction. The Warfarin Re-Infarction Study

High levels of fibrinogen and clotting factor VII are associated with an increased risk for subsequent death and cardiovascular disease in apparently healthy individuals. Furthermore, pathoanatomic studies and coronary angiography have confirmed a relationship between coronary thrombus formation and acute Q-wave infarction. Effective antithrombotic agents may prevent or limit thrombus formation and events related to thrombosis. The Warfarin Re-Infarction Study (WARIS) studied the effect of warfarin in survivors of acute myocardial infarction. Patients aged 75 years or less were randomized in a double-blind, placebo-controlled study to test whether long-term treatment with warfarin reduces the risk of death, reinfarction, and thromboembolic morbidity. A total of 1918 patients were screened for participation; 1214 were recruited. The mean follow-up was 37 months. Analyzed on an intention-to-treat basis, 123 (20%) in the placebo group died, versus 94 (15%) in the warfarin group, a risk reduction of 24% (P = 0.026). Considering patients on treatment or within 28 days after discontinuing the test medication, 92 in the placebo group died, as compared with 60 of the warfarin-treated patients, a risk reduction of 35% (P = 0.005). Relapsing myocardial infarction (fatal and nonfatal) was reduced by 43% (P = 0.0001). The incidence of cerebrovascular attacks was lower in the warfarin group (16 patients) than the placebo group (41 patients), a highly significant reduction of 61% (P = 0.0003). Serious bleeding occurred in 11 patients taking warfarin, an incidence of 0.6% per year. In conclusion, long-term anticoagulant therapy may be recommended after acute myocardial infarction.

Meta-analysis

Meta-analysis corresponds to all systematic methods which use statistical techniques for combining results from several independent studies. The aim is to get a consistent estimation of the global effect of a procedure on a specified outcome. The technique allows us to increase the power of statistical testing, and to get information which cannot be drawn from one individual study. Two approaches are possible, and often combined: the qualitative approach consists of weighing various studies according to their methodological quality; the quantitative approach consists of pooling the results of different studies, in order to generate results with a higher statistical power. A meta-analysis is a long and rigorous process, which follows several steps: statement of objectives; definition of articles inclusion and exclusion criteria; literature search; collection of data and evaluation of the quality of each study; tests for homogeneity; pooling; sensitivity analyses; presentation of results; and conclusions. Meta-analysis has several advantages: it estimates the size of an effect; it improves the generalizability; it compels to rigor; it lessens the part of subjectivity. When meta-analysis is cautiously and properly done, it brings new useful information, and helps physicians and health policy makers in answering to a specific question.

Antithrombotic therapy in historical perspective

The history of antithrombotic therapy is traced over the past 5 decades, with a focus on the treatment of 2 major disorders: venous thromboembolism and acute myocardial infarction. Five subjects pertinent to clinical management decisions are discussed: (1) theories of thrombosis and coagulation, (2) tests of coagulation, (3) the availability of therapeutic interventions, (4) techniques for the diagnosis of vascular obstruction, and (5) the use and misuse of clinical trials.

Do corticosteroids prevent postherpetic neuralgia? A review of the evidence

A short course of corticosteroids is frequently used in herpes zoster to prevent postherpetic neuralgia. To clarify the evidence behind this routine practice, we reviewed the three randomized controlled trials on this subject. Although in all three similar dosages of corticosteroids (40 mg to 60 mg prednisone daily for 2 to 4 weeks) were used, deficiencies in reported clinical characteristics of study subjects, the potential for bias in the ascertainment of pain duration, and the inability to exclude type II error make it impossible to determine whether or not this practice is effective. More research on this subject is needed, with greater attention to good study methodology.

Resolving conflicting clinical trials: guidelines for meta-analysis

Contradictory results among randomized clinical trials addressing similar questions are common and occur when the conclusions of different groups of investigators disagree, or when the results of several trials are statistically inconclusive. Meta-analysis, a term used to describe the process of evaluating and combining the results of conflicting studies, has been proposed as a method for reconciling the contradictory results. In this review of meta-analyses, we distinguish between the pooled and methodologic techniques, described the highly variable strategies used, and propose guidelines for improving the conduct of meta-analyses. In pooled analyses the results of multiple clinical trials are combined and the outcome is compared for patients receiving the principal and comparative therapy. In methodologic analyses the clinical trials are judged according to a set of standards used to assess scientific validity and clinical applicability. Since neither technique alone appeared satisfactory for resolving the conflicting results, we propose an approach to meta-analysis that requires methodologic criteria to identify scientifically valid studies, and pooling criteria to combine data from each of the studies. We believe this new strategy of meta-analysis will have enhanced scientific validity and clinical applicability.

Medical versus early surgical therapy in patients with triple-vessel disease and mild angina pectoris: a CASS registry study of survival

Results of coronary artery bypass grafting were evaluated in 856 nonrandomized patients in the Coronary Artery Surgery Study (CASS) registry with mild angina (Canadian Cardiovascular Society Classes I and II) and three-vessel disease, defined as 70% or more stenosis in the proximal or middle segment of the three major coronary arteries. There were 413 patients with medical therapy and 443 with early operation. Patients with delayed operation were kept in the medical group for analysis. Six-year survival adjusted for left ventricular (LV) function and number of proximal stenoses was 67% for medical and 84% for surgical patients (p less than 0.0001). Patients with normal LV function had equal survival with medicine or surgical intervention. Those with mild or moderate LV dysfunction (CASS LV wall motion score 6 to 9 and 10 to 15, respectively) and at least one proximal stenosis (the dominant right coronary artery) had increased probability of being alive at six years with surgical treatment. In patients with severe LV impairment (LV score higher than 15) and in those whose only proximal stenosis of 70% or more (in three-vessel disease) was located in the left anterior descending coronary artery, increased survival with surgical treatment could not be demonstrated. This is a nonrandomized observational study with the limitations of such studies: the need to adjust for differences in baseline traits between medical and surgical groups and the possibility of an unrecognized imbalance in baseline characteristics. In a Cox analysis of variables influencing outcome, early surgical treatment was an independent predictor of survival with 43% the risk of medical treatment (95% confidence range: 29 to 62%). Adjustment by propensity analysis to reduce selection bias from known differences in baseline variables did not alter results.

Development and evaluation of a one-month research track in emergency medicine for medical students

We present our experience with the development and evaluation of a one-month research track in emergency medicine for medical students. The curriculum includes reading and problem-solving in research methods, biostatistics, and design (80 hours); data collection in one or more of the ongoing studies in the department (usually chart review--40 to 60 hours); one major literature search using Index Medicus and Science Citation Index (20 to 40 hours); and participation in all research-related meetings in the Division, as well as the hospital's Institutional Review Board. Evaluation of the student is done by a pretest and final exam covering the topics of the readings. Pre- and post-testing demonstrated increased understanding of basic research concepts and the use of statistics.

Corticosteroids in stable chronic obstructive pulmonary disease: reappraisal of efficacy

Although systemic corticosteroids are widely used in treating stable chronic obstructive pulmonary disease (COPD), the evidence for their efficacy is still disputed. To reappraise this evidence, the authors used a new analytic strategy in which the 14 available randomized clinical trials were evaluated according to a methodologic "review of systems" and an examination of the statistical precision of the outcome results. Although none of the trials satisfied all of the methodologic criteria for both validity and clinical pertinence, the trials finding steroids efficacious were generally better designed and more statistically precise than trials failing to show efficacy. The authors propose a set of five main methodologic guidelines that require a stable baseline state, a crossover design with suitable washout, adequate doses of corticosteroids, pragmatic designs, and comprehensive choices of outcome events. Attention to these guidelines can help improve both design and evaluation for future trials of systemic steroids for stable COPD.

The application of clinical toxicology

The objective of this review is to assess the role of clinical toxicology as it is practiced today and its possible future development. This includes the legal and ethical aspects of the subject and their application to man. The following issues are considered: extrapolation from animal to man; the logical sequence of the implementation of the stages that constitute good clinical practice; examples of the main invasive and noninvasive techniques employed in the clinical studies; the monitoring of the health of the employee in his working environment; chemically induced chronic disease states; and a retrospective consideration of specific examples of chemical hazards.

Assessing illness severity: does clinical judgment work?

Accurate classification of clinical severity is important for interpreting casemix in clinical studies and for stratifying patients for clinical trials. To evaluate whether clinical judgment might be an effective method of estimating severity, all 604 patients admitted to the medical service in a one month period were rated at the time of admission by the responsible resident as to how sick they were. Within the 13 comorbid disease groups, and within the 15 basic categories of reason for admission, the physicians' severity ratings were the most significant predictor of in-hospital mortality. Death rates rose from 0% in those rated as not ill, to 2% in the mildly ill, to 6% in the moderately ill, to 23% in the severely ill, and to 58% in those rated as moribund (p less than 0.001). Sickness ratings also predicted time to death: mildly ill patients died after prolonged hospitalizations, while the moribund died shortly after admission. The patients' age, sex, race, the number of comorbid diseases or problems did not predict mortality. Patients with serious comorbidity (metastases, AIDS, or cirrhosis) had a higher mortality rate than other patients (p less than 0.001); however, the severity ratings predicted outcomes within this group (p less than 0.001) as well as among those without such serious comorbidity (p less than 0.001). Patients who were admitted with acute neurologic (p less than 0.05) or acute cardiovascular (p less than 0.01) events did have an independently worse prognosis. In conclusion, physicians' estimates or sickness provided an accurate estimate of illness severity, with mortality rates that essentially tripled from one stratum to the next. Clinical judgment may suffice to classify the clinical severity of patients at the time of enrollment in prospective trials and can provide a useful method of controlling for casemix.

Clinical prediction rules. Applications and methodological standards

The objective of clinical prediction rules is to reduce the uncertainty inherent in medical practice by defining how to use clinical findings to make predictions. Clinical prediction rules are derived from systematic clinical observations. They can help physicians identify patients who require diagnostic tests, treatment, or hospitalization. Before adopting a prediction rule, clinicians must evaluate its applicability to their patients. We describe methodological standards that can be used to decide whether a prediction rule is suitable for adoption in a clinician's practice. We applied these standards to 33 reports of prediction rules; 42 per cent of the reports contained an adequate description of the prediction rules, the patients, and the clinical setting. The misclassification rate of the rule was measured in only 34 per cent of reports, and the effects of the rule on patient care were described in only 6 per cent of reports. If the objectives of clinical prediction rules are to be fully achieved, authors and readers need to pay close attention to basic principles of study design.

Is the clinical trial evidence about new drugs statistically adequate?

The statistical adequacy of all papers published in the period 1976-80 describing clinical trials of five non-steroidal anti-inflammatory and two analgesic drugs introduced into the UK market in 1978 and 1979 has been assessed using a checklist of simple criteria. Most trials were reported to be randomised and double-blind. Trial designs were less satisfactory in other important respects; the sample size of most trials was inadequate to demonstrate superiority of the new drug compared with an active control therapy. The period of treatment assessment was short in view of the likelihood of prolonged prescription of drugs in these classes. It is suggested that licensing authorities should demand higher standards of clinical trial evidence offered in support of new drugs.

[Low-dose acetylsalicylic acid (100 mg/day) following aortocoronary bypass operation]

A prospective, randomized, double-blind, placebo-controlled trial was conducted to evaluate the efficacy of Acetylsalicylic Acid (ASS) (100 mg/d, starting 24 h after operation) on vein graft patency. Sixty of 88 patients having undergone surgery entered the study; in 24 of 31 patients in the placebo group and 22 of 29 patients in the ASS-group angiography was performed 4 months postoperatively. There were no significant differences between the groups with respect to age, number of diseased vessels or previous myocardial infarctions. Mean number of grafts per patient was 2,2 (placebo) and 1,8 (ASS) for proximal anastomoses (p less than 0.10) and 3.4 (placebo) and 2.6 (ASS) for distal anastomoses (p less than 0.05). Graft occlusion rate for proximal anastomoses was less in the ASS-group, 10% (4/40), as compared with placebo 32% (17/53) (p less than 0.05). Graft occlusion rate for distal anastomoses was also less in the ASS group, 19% (11/57) as compared to 35% (28/81) in the placebo group (p less than 0.10). All grafts were patent in 16/22 patients in the ASS group but only in 9/24 in the placebo group (p less than 0.05). On designation of patients without postoperative angiograms but cardiovascular events as well as those with at least one graft occluded as "failures", the incidence of the latter was 9/29 in the ASS group and 20/31 in the placebo group (p less than 0.05). Early postoperative bleeding was similar in both groups, no side effects of ASS were observed. In this trial with initiation of low - dose ASS therapy 24 h after operation, antiplatelet therapy reduced the graft occlusion rate significantly.

BCG prophylaxis against cancer: methodological evaluation of a continuing controversy

A possible protective effect of tuberculosis against cancer, together with the known immune-stimulating properties of BCG, have motivated 14 investigations of BCG prophylaxis against cancer. The results have been conflicting: 3 studies found high levels of protection, 8 found no effect, and 3 suggested that BCG may actually raise the risk of cancer. To assess whether the inconsistent results could have a methodological basis, we analyzed each study according to several basic criteria necessary for scientific validity in cause-effect research. The analyses showed two major problems: (1) None of the studies used safeguards against detection bias by ensuring that the diagnosis of cancer in vaccinees and non-vaccinees was made with equal follow-up and surveillance procedures, and in an accurate and unbiased fashion; (2) Studies alleging that BCG is carcinogenic were weakened by the inappropriate use of cancer mortality data, by the analysis of multiple BCG-cancer associations without appropriate statistical adjustment, and by post hoc creation of new cancer risk categories after inspection of the data. Since these methodologic inadequacies preclude any firm conclusions about the role of BCG in preventing cancer, a resolution of the controversy will require new research, designed and conducted with greater attention to methodologic principles necessary to ensure scientific validity.

A review of research methodology in an emergency medicine journal

All original articles published in JACEP and Annals of Emergency Medicine in 1972, 1975, 1978, and 1981 were reviewed and classified according to type of article, research design, specific methods utilized, and statistical analyses employed. The number of articles published annually increased during the 10-year period, from 34 in 1972 to 131 in 1981. The percentage of articles devoted to clinical research, basic science, animal studies, and health services research also increased: 1972, 8.8%; 1975, 39.6%; 1978, 41.2%; and 1981, 51.1%. In 1972, only two studies had defined research designs. In 1981, 47 studies had the following research designs: case control, 9; cohort, 9; cross-sectional, 13; uncontrolled clinical trial, 3; non-random clinical trial, 7; and randomized clinical trial, 6. Research methodologies were defined in only two studies published in 1972, but increased in each of the years reviewed to 41 in 1978. The most common methodology was the use of diagnostic categories. In 1972, statistical analysis was limited to descriptive enumeration and was included in only three articles. In 1981, 62 articles contained statistical analyses, including chi square in 11; t test in 6; Fischer's exact test in 2; ANOVA in 4; and P value (method not stated) in 10. This study reveals a major increase in both the quality and quantity of emergency medicine research published during the 10-year period reviewed.

Does drug therapy slow radiographic deterioration in rheumatoid arthritis?

Many clinicians believe that slow-acting therapeutic agents, such as fold, penicillamine, the antimalarials, and cytotoxic drugs, can retard joint destruction in rheumatoid arthritis. We reviewed 60 published studies employing these drugs to evaluate critically the evidence that drug therapy can slow the radiographic progression of disease. Seventeen studies were found that included radiographic assessment of both treated and control groups; they were analyzed using methodologic criteria known to be important in affecting the results of drug trials. In addition to numerous qualitative methodologic deficiencies, many studies showed inadequacies in sample size and duration of treatment, and the drug dosage used varied from one study to another. We found evidence suggesting that both gold and cyclophosphamide can retard radiographic progression of joint destruction. At present, there are too few technically adequate studies to permit even provisional conclusions concerning other agents.

Acute myocardial infarction: survey of urban and rural hospital mortality

Mortality rates for acute myocardial infarction (AMI) in the province of Manitoba were studied by a retrospective, randomized survey of urban and rural hospital records. Urban hospitals had formal coronary care unit (CCU). Selected rural hospitals lacked CCUs but usually possessed portable monitoring and defibrillation equipment. Twenty-seven percent of 852 cases in the study population died. The mortality rate for unequivocal AMI was 14% to 15% to both urban and rural hospitals. Patients with possible AMI had high mortality rates in both facilities (41% to 45%). Subgroup analysis of the definite AMI population failed to reveal statistically significant differences in urban vs rural mortality, although a consistent trend toward superior performance in urban centers was found. The magnitude of the potential of a rural hospital intervention program to reduce the AMI mortality nevertheless appeared to be small.

Prophylactic lidocaine: uncertain benefits in emergency settings

The need to determine whether prophylactic lidocaine has any therapeutic value is generally recognized, and further investigations have been urged: A carefully designed clinical trial of routine lidocaine administration should be carried out to provide definitive information for the physician treating patients who have had myocardial infarction. Such trials should begin immediately, in view of the magnitude of the problem and the fact that routine prophylaxis of arrhythmias after myocardial infarction is not common policy. Such a study, if well designed, can answer the question... Carefully designed trials must be conducted with patients included in the study as soon as possible after the onset of symptoms, preferably during the prehospital phase, and the medication must be administered in a random-controlled fashion. Although these requirements pose no extraordinary problems of research design and method, they lead to prohibiting ethical conflicts. Without resolving these conflicts, through the elaboration of acceptable standards which bypass traditional informed consent, the value of lidocaine prophylaxis will remain uncertain, as will the many other emergency therapeutic maneuvers of unproven effectiveness.

[Controversial viewpoints on the use of historical controls: Is there an all-or-nothing law?]

In the field of clinical trials the choice of appropriate controls has often given rise to controversy. Historical controls rely too often on biased, incomplete, and inappropriate information. Historical controls may be suitable if the natural history of the illness is known and stable or for planning prospective studies. The minimal requirement for use of historical controls is to explain the methods by which the data were collected. When the goal of clinical investigation is to test for a true difference, a randomized clinical study should be performed.

Deciding whether the conclusions of studies are justified: a review

Critical review of original studies is a major source of medical information for the physician; it necessitates a clear understanding of the research objective of the study. The design of the study, whether experimental or observational, should be appropriate to answer the research question and, further, the study should employ accurate and precise measurements on a suitable group of subjects. The critical reader, aware of the principle of study design and analysis, can assess the validity of the author's conclusions through careful review of the article. A guide to the analysis of an original article is presented here. The reader is asked to formulate questions about a study from the abstract. The answers to these questions, which form the basis for acceptance or rejection of the author's conclusions, are in general available in the body of an article. This technique is demonstrated with two fictional studies about patients with angina.

Quality of reports of clinical trials submitted by the drug industry to the Finnish and Swedish control authorities

The purpose of the present study was to investigate the quality of trials used in support of applications for licensing drugs. All applications for psychotropic drugs received by the Finnish and Swedish drug control authorities in the years 1965, 1970, 1974, and 1975 were studied. In addition, a random sample of applications for "other drugs" was selected in Finland. All reports of clinical trials on the therapeutic efficacy of the drugs were included. Many trials were uncontrolled, and in controlled trials major drawbacks in the quality of the trial design and in the accuracy of reporting were often found. The number of patients in each controlled trial was small, and the majority of trials concerned selected groups of patients. Measures of effectiveness were often such that it was impossible to establish the overall benefit of the drug. Treatment times were short. Adverse effects were handled separately and were not adequately combined with efficacy. When a decision about licensure of a drug is made, it is not enough to know that the drug affects body systems, but its therapeutic value should also be established. The trials attached to the applications for licensing did not usually do that.