The Centre for Reviews and Dissemination (CRD)

CRD is part of the National Institute for Health Research (NIHR) and is a department of the University of York. CRD, which was established in 1994, is one of the largest groups in the world engaged exclusively in evidence synthesis in the health field. CRD undertakes systematic reviews evaluating the research evidence on health and public health questions of national and international importance.  They produce the DARE, NHS EED and HTA databases which are used extensively by health professionals, policy makers and researchers around the world.  They also undertake methods research and produce internationally accepted guidelines for undertaking systematic reviews.

CRD databases updated
In the weeks of 04/04/13 to 01/05/13, 152 new records were added to the DARE database.

Abstracts of the week - a selection

• Effect of increased potassium intake on cardiovascular risk factors and disease: systematic review and meta-analyses.  The authors concluded that increased potassium intake reduced blood pressure in people with hypertension with no adverse effect on blood lipid concentrations, catecholamine concentrations or renal function in adults. Higher potassium intake was associated with a 24% lower risk of stroke. Although some results relied upon non-randomised studies which were prone to bias, the review conclusions seem reliable.
• Effect of lower sodium intake on health: systematic review and meta-analyses.  This review found that reduced sodium intake lowered blood pressure and reduced the risk of stroke, without adversely affecting blood lipid levels or renal function. Although some of the results were based on non-randomised cohort studies which are prone to bias, the large size of this review means its results are likely to be reliable.
• Falls prevention interventions for community-dwelling older persons with cognitive impairment: a systematic review.  The authors concluded that the diversity of the interventions, study designs, populations, and quality of the included studies led to conflicting evidence and inconclusive results for fall prevention interventions in this complex population. These conclusions reflect the evidence presented and appear reliable.
• Screening for and treatment of suicide risk relevant to primary care: a systematic review for the US Preventive Services Task Force.  This generally well-conducted review concluded that screening tools, for use in primary care, might help to identify some adults at increased risk of suicide, but not adolescents. Psychotherapy could reduce suicide attempts, in some high-risk adults. Given the evidence presented, these conclusions seem appropriate.
• Use of medications to reduce risk for primary breast cancer: a systematic review for the US Preventive Services Task Force.  The authors concluded that tamoxifen and raloxifene reduced the incidence of invasive breast cancer and fractures, but increased the incidence of thromboembolic events. Tamoxifen was more effective than raloxifene, but it increased the incidence of endometrial cancer and cataracts. Overall, these conclusions are likely to be reliable.
• Accuracy of colposcopy-directed punch biopsies: a systematic review and meta-analysis.  This review concluded that the high sensitivity and low specificity of colposcopy-directed punch biopsy for high-grade cervical intraepithelial neoplasia might be due to verification bias, as most studies only conducted excision in women with a positive punch biopsy. This conclusion is likely to be reliable.
• Antihypertensive effects of olmesartan compared with other angiotensin receptor blockers: a meta-analysis.  This review found that olmesartan was associated with better antihypertensive efficacy than losartan and valsartan, for patients with hypertension. The adverse events with olmesartan were similar to those with the other angiotensin-receptor blockers. The review was generally well conducted, and the authors' conclusions are likely to be reliable.
• A systematic review and meta-analysis of diagnostic performance of imaging in acute cholecystitis.  This well-conducted review concluded that cholescintigraphy was the most accurate imaging modality for the diagnosis of acute cholecystitis, while ultrasound and magnetic resonance imaging were equally associated with substantial error, and computed tomography was under studied. These conclusions accurately reflect the data presented and are likely to be reliable.
• Cognitive behavioral therapy for depression in older people: a meta-analysis and meta-regression of randomized controlled trials.  The authors concluded cognitive-behavioural therapy was significantly more effective at reducing depressive symptoms (regardless of whether rated by clinicians or participants) than treatment as usual or being on a waiting list but not compared to active controls. The authors conclusions reflect the evidence presented and are likely to be reliable.
• Effectiveness and cost-effectiveness of computer and other electronic aids for smoking cessation: a systematic review and network meta-analysis.  This well-conducted review found that computer and other electronic aids increased the likelihood of smoking cessation compared with no intervention or generic self-help materials, but that the effect was small. The authors' conclusions reflect the evidence presented and are likely to be reliable.
• Efficacy of folic acid supplementation in stroke prevention: new insight from a meta-analysis.  This review found that folic acid supplementation was effective for stroke prevention in populations with partial or no folic acid fortification. In addition, larger effects were observed in trials with lower percentage use of statins. The review was well conducted and the authors' conclusions are likely to be reliable.
• Increased treatment-related mortality with additional cisplatin-based chemotherapy in patients with nasopharyngeal carcinoma treated with standard radiotherapy.  The review concluded that compared with radiotherapy alone, cisplatin-based chemotherapy plus radiotherapy increased the risk of treatment-related death and severe acute toxicity in patients with nasopharyngeal carcinoma. The review would have benefited from clearer reporting of methodology, quality assessment and results but the authors’ conclusions were based on the evidence and appear reasonable.
• Is statin use associated with reduced mortality after pneumonia? A systematic review and meta-analysis.  The authors concluded that current statin use was related to decreased mortality following pneumonia. This effect weakened among important subgroups and studies with methodological rigour and required further study via a large randomised controlled trial. This was a well-conducted review. The authors' conclusion appears reliable and justified.
• Is there any difference between blood and crystalloid cardioplegia for myocardial protection during cardiac surgery? A meta-analysis of 5576 patients from 36 randomized trials.  The authors concluded that there was evidence to suggest no superiority between blood and crystalloid cardioplegia in terms of risk of death, myocardial infarction or low cardiac output syndrome in patients undergoing cardiac surgery. This conclusion seems reliable based on the evidence presented.
• Long-term efficacy and safety of varenicline for smoking cessation: a systematic review and meta-analysis of randomized controlled trials.  The authors concluded that compared with placebo, varenicline was associated with a favourable effect on smoking cessation at 52 weeks but adverse psychiatric events required further study. This appeared to be a well-conducted review and the authors' conclusions and recommendations seem reliable.
• Paclitaxel-coated versus uncoated balloon angioplasty reduces target lesion revascularization in patients with femoropopliteal arterial disease: a meta-analysis of randomized trials.  This generally well-conducted review concluded that paclitaxel-coated balloon angioplasty was associated with better efficacy compared with uncoated balloon angioplasty for treating femoropopliteal arterial (thigh artery) disease, with no evidence of differences in safety. Although there were some shortcomings in the review process and a limited evidence base, the authors' conclusions are likely to be reliable.
• Renin-angiotensin system modulators modestly reduce vascular risk in persons with prior stroke.  This review found that treatment with renin-angiotensin system modulators had significant but modest effects on the risk of future stroke events in patients with prior strokes. The review was well conducted and the authors' conclusions are likely to be reliable.
• Selective serotonin reuptake inhibitors and tricyclic antidepressants in the acute treatment of chronic depression and dysthymia: a systematic review and meta-analysis.  The authors concluded that the review provided evidence of the efficacy of selective serotonin reuptake inhibitors and tricyclic antidepressants in the treatment of chronic depression. Selective serotonin reuptake inhibitors demonstrated better acceptability than tricyclic antidepressants. This was a well conducted review. The conclusions reflect the evidence presented and are likely to be reliable.
• The effectiveness of interventions using electronic reminders to improve adherence to chronic medication: a systematic review of the literature.  This generally well-conducted review concluded that electronic reminders improved medication adherence in the short term but long-term effects remained unclear. Although a degree of inconsistency in the results suggested that the findings may not be equally applicable to all types of reminder systems and patient groups, the authors' conclusions reflected the evidence presented and appear to be reliable.
• Effectiveness and safety of antiepileptic medications in patients with epilepsy.  The authors concluded that some older antiepileptic medications had some efficacy advantages over newer antiepileptic medications and others had similar efficacy. All older medications had more adverse events. Innovator and generic versions of an antiepileptic medication showed similar efficacy and safety. This was a well-conducted review. The authors’ conclusions reflect the evidence presented and are likely to be reliable.

Website: University of York Centre for Reviews and Dissemination