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A Antczak-Bouckoms

Publications and source records attributed to A Antczak-Bouckoms.

At least 19 recordsLinked to original sources
PubMed1998

Meta-analysis of multiple outcomes by regression with random effects.

Earlier work showed how to perform fixed-effects meta-analysis of studies or trials when each provides results on more than one outcome per patient and these multiple outcomes are correlated. That fixed-effects generalized-least-squares approach analyzes the multiple outcomes jointly within a single model, and it can include covariates, such as duration of therapy or quality of trial, that may explain observed heterogeneity of results among the trials. Sometimes the covariates explain all the heterogeneity, and the fixed-effects regression model is appropriate. However, unexplained heterogeneity may often remain, even after taking into account known or suspected covariates. Because fixed-effects models do not make allowance for this remaining unexplained heterogeneity, the potential exists for bias in estimated coefficients, standard errors and p-values. We propose two random-effects approaches for the regression meta-analysis of multiple correlated outcomes. We compare their use with fixed-effects models and with separate-outcomes models in a meta-analysis of periodontal clinical trials. A simulation study shows the advantages of the random-effects approach. These methods also facilitate meta-analysis of trials that compare more than two treatments.

Clinical Trials as Topic↗
PubMed1998

The anatomy of clinical research.

Until recently clinical decision-making relied on intuition, unsystematic experiences and pathophysiological rationale. Developments in the understanding of the nature of clinical trials, systematic reviews and techniques to evaluate diagnostic technology over the past 30 years made the evidence-based clinical practice possible. During this period of evolution it became apparent that not all evidence is equal. Studies that use weak designs tend to estimate a greater treatment effect, whereas strong designs yield a more conservative treatment effect. A good number of orthodontic problems lend themselves to investigations of controlled clinical trials. Reports of early treatment effectiveness of malocclusions contained in this issue demonstrate the point.

Decision Making↗
PubMed1995

Quality and effectiveness issues related to oral health.

In recent years, methods have been developed to evaluate effectiveness, cost-effectiveness, and quality of oral health services and delivery mechanisms. These evaluation techniques are important to the application of oral health services, because most oral health services have not been adequately evaluated. For many services, evaluation may not be necessary. However, there is wide variation in clinical practices and accumulating evidence that many health practices, although based on reasonable pathophysiologic grounds, are not resulting in their expected health benefits. This has led to the suggestion that all clinical precepts may be questioned. A number of measures are used by researchers to evaluate the quality and effectiveness of oral health services. These include: Effectiveness and appropriateness: Methods available to assess health practices range from clinical observation to strictly controlled randomized clinical trials. Cost-effectiveness: Benefit-cost and cost effectiveness analyses. Quality: No tool exists that will single-handedly measure quality. Current methodologies should be based on the following three-dimensional conceptual framework: Structure (evaluation of facilities, equipment, personnel, and organization to deliver care), process (observance of the patient-provider interaction), and outcome (measures of health status and patient outcomes). Little to no information on the quality and effectiveness of oral health delivery systems is available in the United States; the most common system in place is solo, private, fee-for-service practice. Specific questions, conditions, or practices that need evaluation include: Alternative frequencies of oral prophylaxis; Use of fluoride and other remineralization techniques for early decay; Alternative methods to replace missing teeth, including the appropriateness of dental implants; Methods to prevent and treat symptoms of dry mouth; Treatment of the medically compromised patient; Prevention of oral complications of cancer treatment; Appropriateness of new and existing diagnostic technologies; Diagnosis and treatment of oral cancer; and Alternative oral health delivery systems, financing, and expanded responsibilities for allied health professionals.

Cost-Benefit Analysis↗
PubMed1995

Multiple-outcomes meta-analysis of treatments for periodontal disease.

The results of periodontal therapy vary by disease severity, outcome measure, and method of data analysis. Several clinical trials and a subsequent meta-analysis have demonstrated that, for teeth with severe disease, surgery decreases probing depth (PD) and increases attachment level (AL) more than non-surgical treatment. For other disease levels, the choice of therapy depends on the outcome measure. When clinical trials use two or more outcome measures (such as PD and AL), investigators ordinarily analyze each outcome separately. When the correlations are incorporated among the outcomes, a meta-analysis can use generalized-least-squares (GLS) regression to analyze multiple outcomes jointly. We applied the GLS multiple-outcomes model in a meta-analysis of 5 trials comparing surgical and non-surgical periodontal treatments, each assessing the outcomes PD and AL one year after treatment. The clinical conclusions are similar to those reported earlier, but our estimates of the relative benefits of surgical and non-surgical treatment should be more accurate, because the GLS method takes into account correlation between AL and PD. When correlations between the two outcomes rise, as they do with increasing severity of disease, the GLS estimates depart from those derived from separate analyses of PD and AL.

Dental Scaling↗
PubMed1994

Natural history of periodontitis and a review of technologies to prevent and treat it.

The development of recommendations for what is acceptable clinical practice for patients with adult periodontitis is challenging. First, how much and what type of evidence is needed? This depends very much on the clinical problem, the nature of the evidence that is available, and the potential ill effects that may ensue if the effects of the treatment that is recommended are not what they are hoped to be. All treatments are applied with the implicit assumption that they do more good than harm. Treatments that are expensive, invasive, irreversible, or potentially risky, require more evidence than treatments that are not invasive, have reversible effects, and are without risk. Recall the hierarchy of types of evidence used in the AHCPR pain guidelines ranging from a meta-analysis of RCTs to uncontrolled observations in patients or expert opinion. A randomized controlled trial, or a meta-analysis of RCTs carries more weight than a much larger series of cases because of the great potential for bias when observations are made under uncontrolled conditions. One hundred poorly controlled studies do not provide evidence for optimal clinical decisions. Second, who bears the burden of proof? Certainly, any newly proposed therapy must be proven safe and effective by its proponents. But, what about treatments that have been the standard of practice, can they be grandfathered in, or must evidence be gathered for them? Given changes in understanding of mechanisms of disease pathogenesis, classification, rates of activity, and measurement of outcomes, it may be time to call all clinical dogma regarding treatment of adult periodontitis into question. Reliable evidence is not available for many of the treatments for adult periodontitis. Most of the evidence that is available was collected using methods and an underlying conceptual scheme regarding diagnosis and progression of disease that is very different from current beliefs. One could argue that even for the treatments that have been evaluated in RCTs, disease activity rates were so low by current assessment, that there was no disease to prevent or treat.

Disease Progression↗
PubMed1993

Assessing the effectiveness of ambulatory cardiac monitoring for specific clinical indications. Introduction.

This introduction and the three essays that follow examine ambulatory cardiac monitoring for specific clinical indications. They also examine the ways in which evidence from the literature may be synthesized through the framework of decision analysis to guide its appropriate use and identify areas in which more research is needed. The essays discuss ambulatory cardiac monitoring for evaluation of syncope in the elderly; detection of silent ischemia after a myocardial infarction; and selection of antiarrhythmic drugs for malignant ventricular arrhythmias.

Aged↗
PubMed1993

Ambulatory cardiac monitoring for the evaluation of antiarrhythmic agents.

This decision-analysis model assesses ambulatory cardiac monitoring (ACM), ACM followed by exercise testing, and electrophysiologic studies (EPS) in the evaluation and selection of antiarrhythmic agents in postinfarct patients with malignant arrhythmias. With existing data, we find no consistent advantage for one method of drug testing over another, although ACM appears to require fewer resources than does EPS. More patients qualify for EPS, but this fact does not increase the proportion of patients for whom a drug can be identified. These methods may test different aspects of arrhythmia activity and drug response, and sequential use may provide additional benefits. Such benefits must be determined empirically.

Anti-Arrhythmia Agents↗
PubMed1993

Meta-analysis of surgical versus non-surgical methods of treatment for periodontal disease.

A meta-analysis was performed on 5 randomized controlled trials comparing surgical with non-surgical treatment for periodontal disease. The specific procedures considered were the modified Widman flap compared with scaling and root planning or curettage with anesthesia. We chose the most consistently reported outcomes, pocket depth and attachment level, for analysis. At 1 year of follow-up, surgical treatment reduced pocket depth more than non-surgical for all initial levels of disease, but by 5 years, only the deepest initial pockets (> 7 mm) showed significant improvement over non-surgically treated teeth (0.51 mm reduction, p < 0.01). Attachment level showed significantly better early results for non-surgical treatment for less diseased teeth, but by 5 years, all significant differences had disappeared. We computed quality scores following a method described by Chalmers. The mean quality score for study data analysis and presentation was 0.37 +/- 0.009 and for the study protocol, the mean quality score was 0.19 +/- 0.002. We find that this meta-analysis supports findings relating response to therapy with initial level of disease severity. We also find that the choice of outcome measure influences the choice of therapy, with surgical therapy providing greater benefit for probing depth and non-surgical therapy providing greater benefit for attachment level. These results must be viewed, however, in light of the low quality scores of the evaluated studies and the potential for bias due to lack of binding, the small mean treatment differences, and the observer measurement variability.

Analysis of Variance↗
PubMed1992

Quality assessment and meta-analysis of systemic tetracycline use in chronic adult periodontitis.

The use of systemic tetracycline in the treatment of periodontal disease has been controversial. To investigate this controversy, we performed a quality assessment and attempted to perform a meta-analysis of 13 published studies. We evaluated the quality of the study protocol and data analysis and presentation for each study. We were unable to combine data from the majority of studies due to heterogeneity of the outcomes evaluated and limitations in data reported in the individual studies. Therefore, only 2 studies were included in the quantitative meta-analysis. On a scale of 0-1, the mean score for this group of studies was 0.27 (+/- 0.19) for study protocol and 0.31 (+/- 0.11) for data analysis and presentation. Mean reduction in probing depth for the group treated with tetracycline plus scaling was 2.45 mm; for the group which received only scaling, 2.02 mm; for the group that received only tetracycline, 1.98 mm; and for the control group, 0.65 mm. We conclude that analysis of data from the published literature does not demonstrate that the use of systemic tetracycline is more beneficial than conventional treatment in the management of adult periodontal disease. More information is needed in order to perform an extensive meta-analysis of this subject.

Adult↗
PubMed1992

Update on technology assessment in dentistry.

This review focuses on evaluations of particular clinical problems or technologies in dentistry that have used the recently developed technology assessment techniques of decision analysis, meta-analysis, and cost-effectiveness analysis. It also discusses general methodologic and implementation issues in the assessment of health-care technologies.

Cost-Benefit Analysis↗
PubMed1991

Technology assessment in the Normative Aging Study.

This review of publications based on data from the Veterans Affairs Normative Aging Study identified four articles that were considered assessments of health care technologies. Three evaluated methods for research on body composition, the fourth studied ventricular size in patient with presenile dementia. Several additional articles are discussed that provided data on baseline values or risk factors for disease that might be useful in generating hypotheses to be tested in later assessments of technologies.

Aging↗
PubMed1991

Technology assessment in the Veterans Administration Dental Longitudinal Study.

Of the 52 studies emanating from the Veterans Affairs Dental Longitudinal Study, 6 were identified as technology assessments. Three of these studies evaluated dental radiographs used for the diagnosis of oral lesions. Two studies compared alternative technologies for the replacement of missing teeth, and one reported the effects of NSAIDs on alveolar bone loss. Four additional articles are discussed that provide data that will be useful in future assessments of dental technologies.

Aged↗