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Biomedical subjects

Benjamin Djulbegovic

Publications and source records attributed to Benjamin Djulbegovic.

At least 19 recordsLinked to original sources
PubMed2003

Pharmaceutical industry sponsorship and research outcome and quality: systematic review.

OBJECTIVE: To investigate whether funding of drug studies by the pharmaceutical industry is associated with outcomes that are favourable to the funder and whether the methods of trials funded by pharmaceutical companies differ from the methods in trials with other sources of support. METHODS: Medline (January 1966 to December 2002) and Embase (January 1980 to December 2002) searches were supplemented with material identified in the references and in the authors' personal files. Data were independently abstracted by three of the authors and disagreements were resolved by consensus. RESULTS: 30 studies were included. Research funded by drug companies was less likely to be published than research funded by other sources. Studies sponsored by pharmaceutical companies were more likely to have outcomes favouring the sponsor than were studies with other sponsors (odds ratio 4.05; 95% confidence interval 2.98 to 5.51; 18 comparisons). None of the 13 studies that analysed methods reported that studies funded by industry was of poorer quality. CONCLUSION: Systematic bias favours products which are made by the company funding the research. Explanations include the selection of an inappropriate comparator to the product being investigated and publication bias.

Clinical Trials as Topic↗
PubMed2003

Choosing a control intervention for a randomised clinical trial.

BACKGROUND: Randomised controlled clinical trials are performed to resolve uncertainty concerning comparator interventions. Appropriate acknowledgment of uncertainty enables the concurrent achievement of two goals : the acquisition of valuable scientific knowledge and an optimum treatment choice for the patient-participant. The ethical recruitment of patients requires the presence of clinical equipoise. This involves the appropriate choice of a control intervention, particularly when unapproved drugs or innovative interventions are being evaluated. DISCUSSION: We argue that the choice of a control intervention should be supported by a systematic review of the relevant literature and, where necessary, solicitation of the informed beliefs of clinical experts through formal surveys and publication of the proposed trial's protocol. SUMMARY: When clinical equipoise is present, physicians may confidently propose trial enrollment to their eligible patients as an act of therapeutic beneficence.

Control Groups↗
PubMed2003

Management of multiple myeloma: a systematic review and critical appraisal of published studies.

We have done a systematic review of all randomised studies in myeloma, identified through a comprehensive search. Our aim was to investigate and critically examine the effects of various treatment modalities on outcome in patients with multiple myeloma and address 22 specific clinical questions in the management of this disease. As a result of our analysis we identified two therapeutic advances in the management of myeloma that, according to the evidence, are most important for improving outcome. These advances were: introduction of high dose chemotherapy, which appears to be superior to conventional chemotherapy, and the use of bisphosphonates, which decrease the probability of pathological vertebral fractures. However, the overall quality of the body of evidence for myeloma management was poor. Many trials were done with small sample sizes, and did not include reporting power analysis. The majority of studies had inadequate allocation concealment, and few were analysed according to intention to treat principle. We conclude that the quality of total evidence supporting treatment recommendations in myeloma is modest at best and has an ample scope for improvement.

Antineoplastic Agents, Alkylating↗
PubMed2002

Use of epoetin in patients with cancer: evidence-based clinical practice guidelines of the American Society of Clinical Oncology and the American Society of Hematology.

Anemia resulting from cancer or its treatment is an important clinical problem increasingly treated with the recombinant hematopoietic growth factor erythropoietin. To address uncertainties regarding indications and efficacy, the American Society of Clinical Oncology and the American Society of Hematology developed an evidence-based clinical practice guideline for the use of epoetin in patients with cancer. The guideline panel found good evidence to recommend use of epoetin as a treatment option for patients with chemotherapy-associated anemia with a hemoglobin (Hgb) concentration below 10 g/dL. Use of epoetin for patients with less severe anemia (Hgb level below 12 g/dL but never below 10 g/dL) should be determined by clinical circumstances. Good evidence from clinical trials supports the use of subcutaneous epoetin thrice weekly (150 U/kg) for a minimum of 4 weeks. Less strong evidence supports an alternative weekly (40 000 U/wk) dosing regimen, based on common clinical practice. With either administration schedule, dose escalation should be considered for those not responding to the initial dose. In the absence of response, continuing epoetin beyond 6-8 weeks does not appear to be beneficial. Epoetin should be titrated once the hemoglobin concentration reaches 12 g/dL. Evidence from one randomized controlled trial supports use of epoetin for patients with anemia associated with low-risk myelodysplasia not receiving chemotherapy; however, there are no published high-quality studies to support its use for anemia in other hematologic malignancies in the absence of chemotherapy. Therefore, for anemic patients with hematologic malignancies it is recommended that physicians initiate conventional therapy and observe hematologic response before considering use of epoetin.

Anemia↗
PubMed2002

Use of epoetin in patients with cancer: evidence-based clinical practice guidelines of the American Society of Clinical Oncology and the American Society of Hematology.

Anemia resulting from cancer, or its treatment, is an important clinical problem increasingly treated with the recombinant hematopoietic growth factor erythropoietin. To address uncertainties regarding indications and efficacy, the American Society of Clinical Oncology and the American Society of Hematology developed an evidence-based clinical practice guideline for the use of epoetin in patients with cancer. The guideline panel found good evidence to recommend use of epoetin as a treatment option for patients with chemotherapy-associated anemia with a hemoglobin level less than 10 g/dL. Use of epoetin for patients with less severe anemia (hemoglobin < 12 g/dL but never below 10 g/dL) should be determined by clinical circumstances. Good evidence from clinical trials supports the use of subcutaneous epoetin thrice weekly (150 U/kg tiw) for a minimum of 4 weeks. Less strong evidence supports an alternative weekly (40,000 U/wk) dosing regimen, based on common clinical practice. With either administration schedule, dose escalation should be considered for those not responding to the initial dose. In the absence of response, continuing epoetin beyond 6 to 8 weeks does not appear to be beneficial. Epoetin should be titrated once the hemoglobin concentration reaches 12 g/dL. Evidence from one randomized controlled trial supports use of epoetin for patients with anemia associated with low-risk myelodysplasia not receiving chemotherapy; however, there are no published high-quality studies to support its use for anemia in other hematologic malignancies in the absence of chemotherapy. Therefore, for anemic patients with hematologic malignancies, it is recommended that physicians initiate conventional therapy and observe hematologic response before considering use of epoetin.

Anemia↗
PubMed2002

Erythropoietin, uncertainty principle and cancer related anaemia.

BACKGROUND: This study was designed to evaluate if erythropoietin (EPO) is effective in the treatment of cancer related anemia, and if its effect remains unchanged when data are analyzed according to various clinical and methodological characteristics of the studies. We also wanted to demonstrate that cumulative meta-analysis (CMA) can be used to resolve uncertainty regarding clinical questions. METHODS: Systematic Review (SR) of the published literature on the role of EPO in cancer-related anemia. A cumulative meta-analysis (CMA) using a conservative approach was performed to determine the point in time when uncertainty about the effect of EPO on transfusion-related outcomes could be considered resolved. PARTICIPANTS: Patients included in randomized studies that compared EPO versus no therapy or placebo. MAIN OUTCOME MEASURES: Number of patients requiring transfusions. RESULTS: Nineteen trials were included. The pooled results indicated a significant effect of EPO in reducing the number of patients requiring transfusions [odds ratio (OR) = 0.41; 95%CI: 0.33 to 0.5; p < 0.00001;relative risk (RR) = 0.61; 95% CI: 0.54 to 0.68]. The results remain unchanged after the sensitivity analyses were performed according to the various clinical and methodological characteristics of the studies. The heterogeneity was less pronounced when OR was used instead of RR as the measure of the summary point estimate. Analysis according to OR was not heterogeneous, but the pooled RR was highly heterogeneous. A stepwise metaregression analysis did point to the possibility that treatment effect could have been exaggerated by inadequacy in allocation concealment and that larger treatment effects are seen at hb level > 11.5 g/dl. We identified 1995 as the point in time when a statistically significant effect of EPO was demonstrated and after which we considered that uncertainty about EPO efficacy was resolved. CONCLUSION: EPO is effective in the treatment of anemia in cancer patients. This could have already been known in 1995 if a CMA had been performed at that time.

Anemia↗
PubMed2002

Prophylactic granulocyte colony-stimulating factor in patients receiving dose-intensive cancer chemotherapy: a meta-analysis.

PURPOSE: Several studies have evaluated the efficacy of the recombinant colony-stimulating factors in reducing the severity and duration of neutropenia and the risk of infection associated with dose-intensive cancer chemotherapy. We performed a meta-analysis to define better the magnitude of this effect and to assess the generalizability of the results among different diseases and types of treatment. MATERIALS AND METHODS: We used electronic databases and citation lists to identify controlled clinical trials of the prophylactic efficacy of the colony-stimulating factors on neutropenic complications. We selected randomized trials of the use of recombinant colony-stimulating factors before the onset of fever or neutropenia following systemic chemotherapy for solid tumors or malignant lymphomas. RESULTS: We identified eight controlled trials (n = 1144 patients) of prophylactic colony-stimulating factors, including five trials of filgrastim (recombinant granulocyte colony-stimulating factors) and three studies of lenograstim (glycosylated granulocyte recombinant colony-stimulating factors). Five trials were double-blind and placebo-controlled; three included untreated controls. Use of recombinant colony-stimulating factors was associated with a reduced risk of febrile neutropenia (odds ratio [OR] = 0.38; 95% confidence interval [CI]: 0.29 to 0.49), documented infection (OR = 0.51; 95% CI: 0.36 to 0.73), and infection-related mortality (OR = 0.60; 95% CI: 0.30 to 1.22), but a greater risk of bone pain (OR = 2.9; 95% CI: 1.6 to 4.8). CONCLUSION: In this meta-analysis, recombinant colony-stimulating factors were effective in reducing the risk of febrile neutropenia and documented infection associated with several malignancies and dose-intensive treatment regimens.

Antineoplastic Agents↗
PubMed2002

Quality and methods of developing practice guidelines.

BACKGROUND: It is not known whether there are differences in the quality and recommendations between evidence-based (EB) and consensus-based (CB) guidelines. We used breast cancer guidelines as a case study to assess for these differences. METHODS: Five different instruments to evaluate the quality of guidelines were identified by a literature search. We also searched MEDLINE and the Internet to locate 8 breast cancer guidelines. These guidelines were classified in three categories: evidence based, consensus based and consensus based with no explicit consideration of evidence (CB-EB). Each guideline was evaluated by three of the authors using each of the instruments. For each guideline we assessed the agreement among 14 decision points which were selected from the NCCN (National Cancer Comprehensive Network) guidelines algorithm. For each decision point we recorded the level of the quality of the information used to support it. A regression analysis was performed to assess if the percentage of high quality evidence used in the guidelines development was related to the overall quality of the guidelines. RESULTS: Three guidelines were classified as EB, three as CB-EB and two as CB. The EB guidelines scored better than CB, with the CB-EB scoring in the middle among all instruments for guidelines quality assessment. No major disagreement in recommendations was detected among the guidelines regardless of the method used for development, but the EB guidelines had a better agreement with the benchmark guideline for any decision point. When the source of evidence used to support decision were of high quality, we found a higher level of full agreement among the guidelines' recommendations. Up to 94% of variation in the quality score among guidelines could be explained by the quality of evidence used for guidelines development. CONCLUSION: EB guidelines have a better quality than CB guidelines and CB-EB guidelines. Explicit use of high quality evidence can lead to a better agreement among recommendations. However, no major disagreement among guidelines was noted regardless of the method for their development.

Algorithms↗
PubMed2002

Human recombinant erythropoietin and quality of life: a wonder drug or something to wonder about?

Over the past decade an increasing number of studies have supported the use of recombinant human erythropoietin (epoetin) in cancer patients, suggesting that it improves haemoglobin concentrations for some. There is also evidence that this treatment may lead to improvement in quality of life for cancer patients. This systematic review examines the issue. We identified and critically reviewed 13 trials. Although some of the results indicate that epoetin has positive effects on quality of life, methodological limitations inherent in most of the studies hamper interpretation of data. Evidence from this review suggests that more robust designs are required to show any significant quality-of-life benefits for cancer patients undergoing epoetin treatment.

Anemia↗
PubMed2002

At what degree of belief in a research hypothesis is a trial in humans justified?

RATIONALE, AIMS AND OBJECTIVES: Randomized controlled trials (RCTs) have emerged as the most reliable method of assessing the effects of health care interventions in clinical medicine. However, RCTs should be undertaken only if there is substantial uncertainty about which of the trial treatments would benefit a patient most. The purpose of this study is to determine the degree of uncertainty in a research hypothesis before it can empirically be tested in an RCT. METHODS: We integrated arguments from three independent lines of research - on ethics, principles of the design and conduct of clinical trials, and medical decision making - to develop a decision model to help solve the dilemma of under which circumstances innovative treatments should be tested in an RCT. RESULTS: We showed that RCTs are the preferable option to resolve uncertainties about competing treatment alternatives whenever we desire reliable, undisputed, high-quality evidence with a low likelihood of false-positive or false-negative results. CONCLUSIONS: When the expected benefit:risk ratio of a new treatment is small, an RCT is justified to resolve uncertainties over a wide range of prior belief (e.g. 10-90) in the accuracy of the research hypothesis. Randomized controlled trials represent the best means for resolving uncertainties about health care interventions.

Decision Support Techniques↗