Cochrane Collaboration

About: Cochrane Collaboration is a nonprofit organization based out in Oxford, United Kingdom. It is known for research contribution in the topics: Systematic review & Randomized controlled trial. The organization has 1995 authors who have published 3928 publications receiving 382695 citations.

Duloxetine for treating painful neuropathy or chronic pain.

Abstract: Background Duloxetine is a balanced serotonin and noradrenaline reuptake inhibitor licensed for the treatment of major depressive disorders, urinary stress incontinence and the management of neuropathic pain associated with diabetic peripheral neuropathy. A number of trials have been conducted to investigate the use of duloxetine in neuropathic and nociceptive painful conditions. Objectives To assess the benefits and harms of duloxetine for treating painful neuropathy and different types of chronic pain. Search strategy We searched The Cochrane Neuromuscular Group Specialized Register (10 March 2009), The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2009), MEDLINE (January 1966 to March 2009), EMBASE (January 1980 to March 2009), and www.clinicaltrials.gov to March 2009 and the reference lists of identified publications for trials of duloxetine used for the treatment of painful peripheral neuropathy or chronic pain. Selection criteria We selected all randomised or quasi-randomised trials of any formulation of duloxetine, used for the treatment of painful peripheral neuropathy or chronic pain in adult participants. Data collection and analysis Two authors extracted data independently onto a specially designed proforma and cross checked them. Main results Six trials were identified including 2220 participants. Three studies included participants with painful diabetic neuropathy and three treated participants with fibromyalgia. Duloxetine at 60 mg daily is effective in treating painful diabetic peripheral neuropathy in the short-term to 12 weeks with a risk ratio (RR) for 50% pain reduction at 12 weeks of 1.65 (95% confidence interval (CI) 1.34 to 2.03), number needed to treat (NNT) 6 (95% CI 5 to 10). Duloxetine at 60 mg daily is also effective in fibromyalgia over 12 weeks (RR 50% reduction in pain 1.57, 95% CI 1.20 to 2.06; NNT 8, 95% CI 5 to 17) and 28 weeks (RR 1.58, 95% CI 1.10 to 2.27). Adverse events were common in both treatment and placebo arms but more common in the treatment arm with a dose dependent effect. Most side effects were minor, but 16% of participants stopped the drug due to side effects. Serious adverse events were rare. Authors' conclusions There is moderately strong evidence that duloxetine 60 mg and 120 mg daily are efficacious for treating pain in diabetic peripheral neuropathy and fibromyalgia but 20 mg daily is not. Minor side effects are common at therapeutic doses but serious side effects are rare. Direct comparisons of duloxetine with other antidepressants and with other drugs already shown to be efficacious in neuropathic pain would be appropriate and should include unbiased economic analyses.

Changes in landscape composition influence the decline of a threatened woodland caribou population.

Abstract: Summary 1 Large-scale habitat loss is frequently identified with loss of biodiversity, but examples of the direct effect of habitat alterations on changes in vital rates remain rare. Quantifying and understanding the relationship between habitat composition and changes in vital rates, however, is essential for the development of effective conservation strategies. 2 It has been suggested that the decline of woodland caribou Rangifer tarandus caribou populations in North America is precipitated by timber harvesting that creates landscapes of early seral forests. Such habitat changes have altered the predator–prey system resulting in asymmetric predation, where predators are maintained by alternative prey (i.e. apparent competition). However, a direct link between habitat condition and caribou population declines has not been documented. 3 We estimated survival probabilities for the threatened arboreal lichen-feeding ecotype of woodland caribou in British Columbia, Canada, at two different spatial scales. At the broader scale, observed variation in adult female survival rates among 10 distinct populations (range = 0·67–0·93) was best explained by variation in the amount of early seral stands within population ranges and population density. At the finer scale, home ranges of caribou killed by predators had lower proportions of old forest and more mid-aged forest as compared with multi-annual home ranges where caribou were alive. 4 These results are consistent with predictions from the apparent competition hypothesis and quantify direct fitness consequences for caribou following habitat alterations. We conclude that apparent competition can cause rapid population declines and even extinction where changes in species composition occur following large scale habitat change.

Data extraction errors in meta-analyses that use standardized mean differences.

Abstract: ContextMeta-analysis of trials that have used different continuous or rating scales to record outcomes of a similar nature requires sophisticated data handling and data transformation to a uniform scale, the standardized mean difference (SMD). It is not known how reliable such meta-analyses are.ObjectiveTo study whether SMDs in meta-analyses are accurate.Data SourcesSystematic review of meta-analyses published in 2004 that reported a result as an SMD, with no language restrictions. Two trials were randomly selected from each meta-analysis. We attempted to replicate the results in each meta-analysis by independently calculating SMD using Hedges adjusted g.Data ExtractionOur primary outcome was the proportion of meta-analyses for which our result differed from that of the authors by 0.1 or more, either for the point estimate or for its confidence interval, for at least 1 of the 2 selected trials. We chose 0.1 as cut point because many commonly used treatments have an effect of 0.1 to 0.5, compared with placebo.ResultsOf the 27 meta-analyses included in this study, we could not replicate the result for at least 1 of the 2 trials within 0.1 in 10 of the meta-analyses (37%), and in 4 cases, the discrepancy was 0.6 or more for the point estimate. Common problems were erroneous number of patients, means, standard deviations, and sign for the effect estimate. In total, 17 meta-analyses (63%) had errors for at least 1 of the 2 trials examined. For the 10 meta-analyses with errors of at least 0.1, we checked the data from all the trials and conducted our own meta-analysis, using the authors' methods. Seven of these 10 meta-analyses were erroneous (70%); 1 was subsequently retracted, and in 2 a significant difference disappeared or appeared.ConclusionsThe high proportion of meta-analyses based on SMDs that show errors indicates that although the statistical process is ostensibly simple, data extraction is particularly liable to errors that can negate or even reverse the findings of the study. This has implications for researchers and implies that all readers, including journal reviewers and policy makers, should approach such meta-analyses with caution.

Population-based study on incidence, risk factors, clinical complications and drug utilisation associated with influenza in the United Kingdom

Abstract: This large population-based study using the UK-based General Practice Research Database was conducted to quantify influenza-related physician visits, clinical complications of and risk factors for influenza, and related drug use in all age groups from 1991 to 1996. A total of 141,293 subjects who had one or more diagnoses of influenza or influenza-like illness during the study period as well as the same number of age-, sex-, practice and calendar time-matched controls were identified. Adults aged 15–64 years had the highest influenza incidence rate. The risk of getting influenza was particularly increased for subjects with chronic respiratory conditions (asthma or chronic obstructive pulmonary disease, odds ratio 1.65, 95% confidence interval 1.60–1.70). Subjects with influenza were more likely to have a diagnosis of clinical complications than control subjects (relative risk 3.4, 95% confidence interval 3.3–3.6). The risk of developing clinical complications was highest for children and was elevated for subjects with certain underlying chronic conditions. In absolute terms, otherwise healthy adults (15–64 years) accounted for the greatest proportion of all influenza-related physician visits as well as clinical complications in this study population. Of the 141,293 subjects with influenza, 83,911 (59.4%) received drugs on prescription. The most frequently prescribed drugs were antibiotics (45.2%), followed by antipyretics/analgesics (22.5%). Influenza patients were approximately six times more likely to use drugs on prescription than controls. This analysis may lead to further analyses on the economic impact of influenza and the contribution of different population groups to that burden.