Therapy of shock with naloxone: a meta-analysis.

OBJECTIVES: To evaluate the effectiveness of naloxone in human shock; and to estimate the methodologic quality of the clinical trials. DATA SOURCES: Computerized bibliographic search on MEDLINE covering the period from January 1979 to July 1996, review of references of all papers found on the subject, and contact with primary investigators of eligible studies. STUDY SELECTION: To be included in this study, a paper should be a randomized, clinical trial published in a peer-reviewed journal evaluating naloxone in human shock, regardless of the patient's age (adult, child, neonate). Three independent readers reviewed 61 human publications and selected five clinical trials. Overall agreement on study selection was perfect (concordance: 100%). We excluded a posteriori two studies whose authors were unable to provide us with the raw data to complete contingency tables. This meta-analysis deals with three studies including 61 patients with septic shock. DATA EXTRACTION: Three independent reviewers extracted data on study design, intervention, outcome, and methodologic quality. The intraclass correlation coefficient was 0.7. The quality score of each study was 48, 60, and 61, on a scale of 104. DATA SYNTHESIS: Naloxone therapy was associated with statistically significant hemodynamic improvement (typical odds ratio: 0.241; 95% confidence interval: 0.08 to 0.68). The overall effect size was 0.89. However, a publication bias was possible. The case fatality rate was not decreased by naloxone (typical odds ratio: 0.60; 95% confidence interval: 0.21 to 1.67); a chi-square analysis detected significant heterogeneity for the latter outcome (p < .05). CONCLUSIONS: Naloxone improves blood pressure. However, the clinical usefulness of naloxone to treat shock remains to be determined and additional randomized clinical trials are needed to assess its usefulness.

A meta-analytic review of the effect of exercise on smoking cessation.

OBJECTIVE: To assess the effect of group exercise programs on smoking cessation. DATA SOURCES: A MEDLINE search, a manual review of journal articles, and a search of previous reviews were used. STUDY SELECTION: Published studies which 1) employed an exercise program for an intervention group and, 2) reported numbers of smokers of both exercise and control groups at baseline and at 6 to 24 months later were selected. DATA EXTRACTION: Five randomized trials were selected. In three of these, smoking cessation was the main aim and exercise was employed for relapse prevention concurrently with or after a group smoking cessation program. The studies produced a moderate qualitative score of 7 to 9 out of a 13 total score of modified DerSimonian's quality checklist. DATA SYNTHESIS: The summary odds ratio of the three studies which primarily aimed at smoking cessation was 2.35 (95% C.I. 0.75-7.31). When the two other studies were added, it dropped to 1.85 (95% C.I. 0.65-5.24). CONCLUSIONS: Due to the small number of studies and the small sample size for each study, the effect remains unclear. Further analysis, both qualitative and quantitative, is necessary to clarify these issues.

Impact of receiving blood cholesterol test results on dietary change.

INTRODUCTION: The study objective was to determine the impact of receiving results of a blood cholesterol test on changes in dietary behaviors among individuals participating in a Health Risk Appraisal Program. METHODS: This randomized trial of maintenance employees at six hospitals included two groups: Group 1 received their blood cholesterol test results at the pretest; Group 2 received results only at the posttest (16-20 weeks later). The pretest interview included (1) a 24-hour dietary recall; (2) an evaluation of dietary behaviors and suggestions on how to change; (3) height, weight, and blood cholesterol measurement. Five hundred employees participated, and 429 eligible employees completed both pretest and posttest interviews. RESULTS: Blood cholesterol levels decreased by 4.8% (P < .001) and saturated fat intake decreased by 7.4% (P < .05). Regression analyses indicated that individuals more likely to have lowered saturated fat intake had higher pretest saturated fat intakes, had a family history of high blood cholesterol, and were light-maintenance employees (P < .05); no other variables were associated (receiving blood cholesterol test results, previous blood cholesterol test, pretest blood cholesterol levels, personal history of heart disease, BMI, age, gender, tobacco/alcohol use). Among subjects with normal cholesterol levels, those not receiving blood test results reduced saturated fat intake more than those receiving test results; both groups had similar saturated fat intakes (> 12%) greater than recommended intake (< 10%). CONCLUSIONS: Screening programs should include an assessment of saturated fat intake as screening for blood cholesterol may provide normocholesterolemic subjects with a false sense of security.

Impact of a false positive blood culture result on the management of febrile children.

OBJECTIVE: To evaluate the impact of a preliminary positive blood culture result, subsequently confirmed to be a false positive blood culture result on rate of hospitalization, antibiotic therapy and use of microbiologic tests. DESIGN: Retrospective chart review. PATIENTS AND METHODS: Children between 1 month and 18 years old on whom a blood culture was performed were eligible, excluding those with an underlying condition for whom a false positive blood culture may be difficult to assess. During the 1-year study period 9959 blood cultures were performed of which 778 (7.8%) produced growth. Charts of 81 patients with a false positive blood culture were reviewed and compared with those of 162 patients with a true negative blood culture. Patients already hospitalized when blood culture was drawn (n = 24) were analyzed separately from those who were not (n = 219). Among these, patients were divided into those who were followed as outpatients (n = 104) and hospitalized (n = 115). RESULTS: Both groups (false positive vs. true negative) were comparable for age, sex, temperature at consultation, white blood cell count and illness severity. Twenty-six percent of patients followed as outpatients who had a false positive blood culture were hospitalized because of a preliminary positive blood culture result. Among patients hospitalized at the initial assessment, the frequency of antibiotic therapy (91% vs. 71%, P < 0.01), the frequency of use of intravenous antibiotics (80% vs. 58%, P < 0.01) and the percentage of unwarranted antibiotic prescription (13% vs. 0%, P < 0.01) were significantly greater in the false positive group than in the true negative group. The same results were found for each of these outcomes among the group of patients followed as outpatients (61% vs. 28%, P < 0.01, 17% vs. 0%, P < 0.01 and 39% vs. 0%, P < 0.01) for false positive vs. true negative, respectively. Patients with false positive blood cultures had more blood cultures drawn subsequently (P < 0.01). Children already hospitalized when the blood culture was obtained did not show significant differences in main outcomes. CONCLUSIONS: False positive blood culture results generate unnecessary hospitalizations, antibiotic therapy and use of microbiologic tests.

Adjuvant chemotherapy in colorectal carcinoma: results of a meta-analysis.

UNLABELLED: Despite the National Institutes of Health consensus regarding use of adjuvant chemotherapy in colorectal carcinoma, many general surgeons question the efficacy of this approach when considering costs involved for both the individual patient and society at large. PURPOSE: This study was designed to determine the real impact of adjuvant chemotherapy on five-year survival rates of patients. METHOD: A qualitative and quantitative meta-analysis of results from 39 randomized clinical trials published from 1959 to 1993 is described. RESULTS: Design quality of clinical trials had a mean score of 48.6 percent (+/-6.2 standard deviation). A small benefit of therapy in terms of overall survival was noted, with a mortality odds ratio (OR) of 0.91 (confidence interval (CI) 95 percent, 0.83-0.99). For the group of colon carcinomas, the OR was 0.81 (CI 95 percent, 0.69-0.94) with an OR of 0.64 (CI 95 percent, 0.48-0.85) for the group of rectal carcinomas. The effect size was 0.09 for the colon group and 0.20 for the rectal group. For those patients who receive chemotherapy, this effect size implies that we can expect an increase of 5 percent in the survival rate in the group with colon carcinoma and a 9 percent increase in the survival rate in the group with rectal carcinoma. CONCLUSION: Given the high incidence of colorectal carcinoma, the small benefit observed for those patients receiving chemotherapy is far from negligible. However, indications for adjuvant chemotherapy warrant further discussion.

Epidemiology, evidenced-based medicine, and evidence-based public health.

Evidence-Based Medicine (EBM) is heralded as a new paradigm of medicine. Is it? What is its link to epidemiology? Does an evidence-based (EB) approach apply also to other health sciences and to public health in particular? What has epidemiology already achieved in these domains, and what remains to be done? What should our priorities be in the coming years? The EB approach is essential in all health sciences at two levels: for problem solving, and for decision making. It applies to all health sciences, be it medicine, nursing, public health, or others. Many epidemiological principles, methods and techniques are put into good use in EBM. The EB "movement" is attractive in it's use of clearly defined procedures, generalizing (not always explicitly) the application of good epidemiologic principles, methods, and techniques. Epidemiology must now contribute to the evaluation of the practice of an EB approach. If one does not have access to a good medical library nor information technology does the EBM paradigm still hold? Hence, clinical and public health guidelines will benefit first from the EBM approach, then daily practice of EBM will follow, conditions permitting. In public health, the challenges of the EB practice are not equally spread across health protection, different levels of disease prevention, and health promotion. The latter represents the most challenging task for epidemiology at any step of EB approach. Epidemiology, if successful in this domain, may help to build an EB health promotion. An Evidence-Based Public Health paradigm may be considered.

[Meta-analysis as a synthesis of clinical and epidemiologic information. Its application to treatments in gynecology and obstetrics]. / La méta-analyse en tant que synthèse de l'information clinique et épidémiologique. Ses applications aux traitements en gynécologie et obstétrique.

Multiple clinical studies require a structured synthesis of their results, especially where heterogeneous results are reported. Meta-analysis is a method that does just that. Such an epidemiological study of results across studies replaces the traditional narrative review of literature, and its study completes, but does not replace medical record linkage. Diuretics in pre-eclampsia, progestational agents in the control of major failures of pregnancy and fetal monitoring as a possible trigger for more frequent caesarean sections are given as examples of interest in gynaecology and obstetrics.

Content and methods of studies on the prevention and treatment of mental disorders in selected psychiatric journals.

Studies on psychiatric treatments published in 1986 were reviewed in five major psychiatric journals (Am. J. Psychiatry, Can. J. Psychiatry, Arch. Gen. Psychiatry, Am. J. Orthopsychiatry and Am. Acad. Child Psychiatry). Articles on prevention and treatment represent only 27% of the total of titles (194 out of 731 articles). The studies reviewed focus mostly on the treatment of adults, on psychoses, on the short term effect of treatment and on the effect of treatment rather than its process. Almost no information is published on the evaluation of the process or on the cost of treatment. Studies are for the most part original, but they tend to be studies without controls rather than randomized or non-randomized controlled trials. Interpretation of results rely essentially on statistical significance and almost no attention is paid to the evaluation of impact, in epidemiological terms, of the cause-effect relationship and to the clinical relevance of observed differences. Psychiatrists who read only a few major journals of psychiatry should get more information on therapeutic and preventive interventions in comparison to other components of clinical work and to clinical course of disease.

Conceptual differences between prevention and health promotion: research implications for community health programs.

We review recent publications on the concepts of health promotion and prevention. These concepts are based on various paradigms which are defined here. A brief history of the evolution in the meaning of health is presented. Attention is turned to the research implications of the new trend of public health programs which focus on health promotion. In Canada, Achieving Health for All: a framework for health promotion is under examination in order to establish objectives and strategies for the development of health promotion programs. However, a well-articulated research strategy is urgently needed to enhance health promotion activities in this country. Disease prevention and health promotion could continue as distinct entities only if clear operational criteria, characteristics and definitions exist for each of them.

Prophylaxis of upper gastrointestinal bleeding in intensive care units: a meta-analysis.

A meta-analysis was performed of 15 randomized studies on the prophylaxis with cimetidine and/or ant-acids of upper GI bleeding acquired in the ICU. There were eight comparisons of a group receiving cimetidine with a control group, nine comparisons of a group receiving antacids with a control group, and ten comparisons of a group receiving cimetidine with a group receiving antacids. The incidence of upper GI bleeding ranged from 3.4% to 52.7% among 866 control patients who received either a placebo or no prophylaxis. In five of eight comparisons, cimetidine was significantly more effective than no treatment or a placebo to prevent occult and overt upper GI bleeding; the typical odds ratio was 0.32 (95% confidence interval 0.21 to 0.49). In six of nine comparisons, antacids were significantly more effective than no treatment or a placebo; the typical odds ratio was 0.12 (0.08 to 0.19). Finally, antacids were significantly more effective than cimetidine in two of ten comparisons; the typical odds ratio was 1.61 (0.97 to 2.65). However, weaknesses in the study designs, heterogeneity of treatment effects, the lack of strength of the accumulated evidence, and the fact that no utility has been shown in terms of reducing morbidity (shock, need for transfusion) or mortality, prevent any definitive conclusion in regard to compulsory use of upper GI bleeding prophylaxis for ICU patients.

Meta-analysis in medicine. Where we are and where we want to go.

An epidemiologically impeccable study does not bring answers to all the important questions. A structured and systematic integration of information from different studies of a given problem with a view to answering the original question or bringing additional information is the essence and objective of the meta-analytic approach to health problem solving. Original studies in medicine, being very heterogeneous in nature and structure require not only a quantitative approach (as in classical meta-analysis) but also an additional "qualitative meta-analysis" as well. The latter represents not only a systematic accumulation of both information and the characteristics of different studies, but also an assessment of quality, uncertainty, missing data, random error and bias across studies of interest. The greatest challenge of meta-analysis in medicine lies in the integration of the qualitative and quantitative assessment of given information (scoring of quality, weighing of the effect size by quality score, etc.). Meta-analysis in medicine must go beyond a simple pooling of data. It should become the "epidemiology of results of independent studies of a common topic of interest". Further development of meta-analysis in such an expanded way may have an important impact on decision-making in clinical medicine, and in health policies.

[More fetal monitoring, more cesarean sections? An attempt at meta-analysis of the problem]. / Plus de monitoring foetal, plus de césariennes? Essai de la méta-analyse du problème.

Has the introduction of continuous intrapartum fetal heart rate (F.H.R.) registration resulted in an increase of cesarean section (CS) rates? Our meta-analysis of literature published since 1970 reveals the weak intrinsic value of retrospective studies and the heterogeneity of randomised trials concerning this question. The impact of routine intrapartum FHR monitoring on CS rates is low--and even null--in selected groups; the relationship diminishes over time.