Assessing the evidence on case management.
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BACKGROUND: Evidence on the impact of case management is contradictory. AIMS: To discuss two different systematic reviews (one conducted by the authors and one conducted through the Cochrane collaboration) that came to contradictory conclusions about the impact of case management in mental health services. METHOD: We summarised the findings of the two reviews with respect to case management effectiveness, examined key methodological differences between the two approaches and discuss the impact of these on the validity of the results. RESULTS: The differences in conclusions between the two reviews result from the differences in inclusion criteria, namely non-randomised trials, data from unpublished scales and data from variables with skewed distributions. The theoretical and empirical effects of these are discussed. CONCLUSIONS: Systematic reviewers may face a trade-off between the application of strict criteria for the inclusion of studies and the amount of data available for analysis and hence statistical power. The available research suggests that case management is generally effective. (+info)
Drought-inhibition of photosynthesis in C3 plants: stomatal and non-stomatal limitations revisited.
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There is a long-standing controversy as to whether drought limits photosynthetic CO2 assimilation through stomatal closure or by metabolic impairment in C3 plants. Comparing results from different studies is difficult due to interspecific differences in the response of photosynthesis to leaf water potential and/or relative water content (RWC), the most commonly used parameters to assess the severity of drought. Therefore, we have used stomatal conductance (g) as a basis for comparison of metabolic processes in different studies. The logic is that, as there is a strong link between g and photosynthesis (perhaps co-regulation between them), so different relationships between RWC or water potential and photosynthetic rate and changes in metabolism in different species and studies may be 'normalized' by relating them to g. Re-analysing data from the literature using light-saturated g as a parameter indicative of water deficits in plants shows that there is good correspondence between the onset of drought-induced inhibition of different photosynthetic sub-processes and g. Contents of ribulose bisphosphate (RuBP) and adenosine triphosphate (ATP) decrease early in drought development, at still relatively high g (higher than 150 mmol H20 m(-2) s(-1)). This suggests that RuBP regeneration and ATP synthesis are impaired. Decreased photochemistry and Rubisco activity typically occur at lower g (<100 mmol H20 m(-2) s(-1)), whereas permanent photoinhibition is only occasional, occurring at very low g (<50 mmol H20 m(-2) s(-1)). Sub-stomatal CO2 concentration decreases as g becomes smaller, but increases again at small g. The analysis suggests that stomatal closure is the earliest response to drought and the dominant limitation to photosynthesis at mild to moderate drought. However, in parallel, progressive down-regulation or inhibition of metabolic processes leads to decreased RuBP content, which becomes the dominant limitation at severe drought, and thereby inhibits photosynthetic CO2 assimilation. (+info)
A new health technology: where is the consensus on a clinically worthwhile benefit?
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AIM: New therapies are often introduced into the NHS prior to full evaluation, leading to inequities in provision. Uncertainty exists regarding the value of photodynamic therapy in the treatment of neovascular age-related macular degeneration. We ascertained the availability of this treatment and the information used to inform clinical policy. METHODS: A postal survey of all clinical directors/lead consultants in the UK sought data on which (if any) patients were referred or treated with PDT by their unit, the sources of evidence informing clinical policy and the threshold of clinical benefit at which respondents would support the use of PDT. RESULTS: 123/152 questionnaires were returned. 42% of units make some provision for PDT on the NHS, including routine provision by 9%. 14.5% of units offer the option of care in the private sector, whilst 26.5% treated or referred no patients. The threshold at which respondents considered introduction of PDT would be justifiable varied widely. Respondents cited local literature review, advice from clinicians, guidance from the Royal College and information from the pharmaceutical industry as most influential in determining current policy. However, the National Institute for Clinical Excellence (NICE) and the Cochrane Library were anticipated as playing a greater role in shaping future practice. CONCLUSIONS: Substantial variation exists in the availability of PDT. Advocates of PDT may interpret our data as an indication of the NHS failing to provide an effective therapy equitably, whilst others may deduce that patients are receiving an under-evaluated treatment in routine clinical practice. The differing thresholds at which clinicians believe treatment would be justified may further exacerbate variations and the priority given to PDT. (+info)
Statistical presentation and analysis of ordered categorical outcome data in rheumatology journals.
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OBJECTIVE: To assess the appropriateness of presentation of summary measures and analysis of ordered categorical (ordinal) data in three rheumatology journals in 1999, and to consider differences between basic and clinical science articles. METHODS: Six hundred forty-four full-length articles from the 1999 editions of 3 rheumatology journals were evaluated for inclusion of an ordinal outcome. Articles were classified as basic or clinical science, and the appropriateness of presentation and analysis of the ordinal outcome were assessed. Chi-square tests were used to evaluate difference in percentages. RESULTS: Ordinal outcomes were identified in 175 (27.2%) of 644 articles. Only 69 (39.4%) had appropriate data presentation, and 111 (63.4%) had appropriate data analysis. Appropriate presentation was seen less commonly in the basic science rather than the clinical science articles, but differences in the occurrence of appropriate analysis were not seen. CONCLUSION: Ordinal data are common in rheumatology articles, but presentation usually does not conform to recommended guidelines. (+info)
Evidence based educational outreach visits: effects on prescriptions of non-steroidal anti-inflammatory drugs.
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AIMS: To evaluate the effectiveness of an evidence based group educational outreach visit on prescription patterns of non-steroidal anti-inflammatory drugs (NSAIDs) in primary care. DESIGN: Randomised controlled simple blind trial, with randomisation into three groups: experimental (evidence based educational outreach visit), placebo (conventional education session), and control (without intervention). SETTING: The 24 primary care centres of the National Institute of Healthcare Network in a rural province of Aragon, Spain. PARTICIPANTS: The 24 primary health care teams of the network, with 158 general practitioners (GPs). The teams were randomised into the groups, experimental (8 teams, 48 GPs), placebo (8 teams, 54 GPs), and control (8 teams, 56 GPs). INTERVENTION: Experimental group: one group educational outreach visit, conveying data based on a systematic review of the literature that was reinforced with printed material; placebo group: one non-structured educational session; control group: no intervention. Both educational sessions emphasised that there are no differences in the effectiveness of the NSAIDs reviewed (diclofenac, piroxicam, and tenoxicam); a recommendation was made to prescribe diclofenac over tenoxicam because of price differences. MAIN OUTCOME MEASURES: Changes in the number of packages prescribed for each of the drugs and changes in the cost per package of NSAIDs prescribed during the six months before, and after the intervention. RESULTS: There were no differences in the basal characteristics of the three groups, except for the number of prescriptions during the six months before the intervention. Prescriptions for NSAIDs decreased homogeneously in the three groups. For tenoxicam, the experimental group reduced prescriptions by 22.5% (95%CI: 34.42 to -10.76), compared with a reduction of 9.78% (95%CI: -17.70 to -1.86) in the placebo group and an increase of 14.44% (95%CI: 5.22 to 23.66) in the control group. The average cost per prescription decreased by 1.91% (95%CI: -0.33% to -3.49%) in the experimental group, 0.16% (95%CI: -0.27% to -2.93%) in the placebo group, and rose by 1.76% (95%CI: 0.35% to 3.17%) in the control group. CONCLUSIONS: Evidence based educational outreach visits are more effective than no intervention at all. Results suggest that evidence based educational outreach visits are incrementally more effective than conventional educational sessions, which in turn are more effective than no intervention at all. (+info)
State-of-the-art treatment of metastatic hormone-refractory prostate cancer.
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Initial therapy for advanced prostate cancer includes androgen ablation by surgical or medical castration. Still, nearly all men with metastases will progress to hormone-refractory prostate cancer (HRPC). Current U.S. Food and Drug Administration-approved agents for the treatment of HRPC include mitoxantrone and estramustine, although the vinca alkaloids and the taxanes have shown promising activity in single-agent phase II trials. Combinations of these agents induce a biochemical response in greater than 50% of patients, but the median duration of response is approximately 6 months. Overall survival of patients treated with these combinations is approximately 18-24 months. Studies are ongoing to develop novel therapies that target specific molecular pathways or mechanisms of chemotherapy resistance. Novel agents under development include growth factor receptor inhibitors, antisense oligonucleotides, bisphosphonates, and cell differentiating agents. Evaluation and incorporation of these agents into existing treatment regimens will guide us in the development of more active regimens in the treatment of HRPC. (+info)
Development and use of a taxonomy to carry out a systematic review of the literature on methods described to effect distal movement of maxillary molars.
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OBJECTIVE: To devise a taxonomy for the assessment of the orthodontic literature on methods described to effect distal movement of maxillary molars, to test the taxonomy for inter-assessor reliability, and to use it to classify studies in a systematic review of the literature. DATA SOURCES: Articles appearing in the American Journal of Orthodontics and Dentofacial Orthopedics, Angle Orthodontist, (British) Journal of Orthodontics, European Journal of Orthodontics, and the Journal of Clinical Orthodontics between 1988 and 1998. Data selection Articles describing or evaluating the effect of appliances known or thought to have a distalizing effect on maxillary molars. DATA EXTRACTION: A taxonomy was designed, tested by two reviewers independently to assess levels of agreement, and then used to record the features of the articles in a systematic review of the literature. DATA SYNTHESIS: Kappa scores were used to assess the level of agreement between reviewers and found to be satisfactory. Studies were grouped according to study design and features of their methodology quantified. CONCLUSIONS: Having devised and tested the taxonomy, we found that the quality of evidence for any method of moving maxillary molars distally was not high. (+info)
Integrating quality into the cycle of therapeutic development.
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The quality of healthcare, particularly as reflected in current practice versus the available evidence, has become a major focus of national health policy discussions. Key components needed to provide quality care include: 1) development of quality indicators and performance measures from specific practice guidelines, 2) better ways to disseminate such guidelines and measures, and 3) development of support tools to promote standardized practice. Although rational decision-making and development of practice guidelines have relied upon results of randomized trials and outcomes studies, not all questions can be answered by randomized trials, and many treatment decisions necessarily reflect physiology, intuition, and experience when treating individuals. Debate about the role of "evidence-based medicine" also has raised questions about the value of applying trial results in practice, and some skepticism has arisen about whether advocated measures of clinical effectiveness, the basic definition of quality, truly reflect a worthwhile approach to improving medical practice. We provide a perspective on this issue by describing a model that integrates quantitative measurements of quality and performance into the development cycle of existing and future therapeutics. Such a model would serve as a basic approach to cardiovascular medicine that is necessary, but not sufficient, to those wishing to provide the best care for their patients. (+info)