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 week of 24/01/13 to 30/01/13, 29 new records were added to the DARE database.

Abstracts of the week - a selection

Early interventions to prevent psychosis: systematic review and meta-analysis. This review assessed interventions to prevent or delay transition to psychosis in high-risk individuals, and concluded that psychological interventions might be effective, but the evidence for specific interventions was not conclusive. This conclusion was based on the quantity and quality of the available evidence and, with their recommendation for further research, is likely to be reliable.
Efficacy of vitamin and antioxidant supplements in prevention of cardiovascular disease: systematic review and meta-analysis of randomised controlled trials. The authors of this review concluded that there was no evidence to support the use of vitamin and antioxidant supplements for the prevention of cardiovascular disease. This review appears to be reliable.
A systematic review of the effectiveness of occupational health and safety training. The review concluded that occupational health and safety training positively affected worker behaviours, but there was insufficient evidence of the effect on health, attitudes and beliefs, and knowledge. The review was generally well conducted, and the authors’ conclusions appropriately acknowledge the limitations in the evidence base and seem reliable.
Comparative effectiveness for survival and renal function of partial and radical nephrectomy for localized renal tumors: a systematic review and meta-analysis. This study suggested that partial nephrectomy produced a survival advantage and a lower risk of severe chronic kidney disease after surgery, compared with radical nephrectomy, for localised renal tumours, but the evidence was of low quality and there was significant heterogeneity across studies. The authors' cautious conclusions reflect the evidence presented and are likely to be reliable.
Comparative effectiveness of antihypertensive medication for primary prevention of cardiovascular disease: systematic review and multiple treatments meta-analysis. This review found that, in general, there was little or no difference between blood pressure lowering medications for primary prevention of cardiovascular disease. The review was well conducted and included a very large number of participants. The authors’ conclusions are appropriate and the results are likely to be reliable.
Effectiveness and safety of pemetrexed-based doublet versus pemetrexed alone as second-line treatment for advanced non-small-cell lung cancer: a systematic review and meta-analysis. The authors concluded that pemetrexed-based doublet therapy did not benefit overall survival, but progression-free survival and overall response rate were improved compared with single-agent pemetrexed for non-small-cell lung cancer. Doublet therapy produced more adverse events. Despite potential weaknesses in the review process, and reliance on limited evidence, the authors' conclusion and research recommendations seem justified.
The effect of telemedicine in critically ill patients: systematic review and meta-analysis. Telemedicine was associated with lower intensive care unit and hospital mortality among critically ill patients. Effects varied among studies and may have been overestimated in non-randomised designs. Optimal telemedicine technology configuration and dose tailored to intensive care unit organisation and case remained unclear. The authors' cautious conclusions reflect the evidence presented and are likely to be reliable.
The impact of prosthesis-patient mismatch on long-term survival after aortic valve replacement: a systematic review and meta-analysis of 34 observational studies comprising 27 186 patients with 133 141 patient-years. This review concluded that prosthesis-patient mismatch (of artificial heart valves) was associated with an increase in all-cause and cardiac-related mortality over long-term follow-up after aortic valve replacement in adult patients. Although there were potential limitations because of the observational nature of the included evidence, the authors' conclusions are likely to be reliable.
Which is the best alternative for displaced femoral neck fractures in the elderly? A meta-analysis. Arthroplasty can reduce the risk of major complications and the incidence of reoperation compared to internal fixation. It provides better pain relief and function, but does not reduce mortality. Despite concerns about study quality and heterogeneity the conclusions generally reflected the evidence presented and are likely to be reliable.
Effects and patient compliance of sustained-release versus immediate-release glipizides in patients with type 2 diabetes mellitus: a systematic review and meta-analysis. This review concluded that sustained-release glipizide appeared to achieve similar glucose control with decreased insulin secretion, fewer hypoglycaemic episodes and higher patient compliance than immediate-release glipizide but the findings were inconclusive due to low study quality, short follow-up and lack of patient important outcomes. These conclusions reflect the evidence presented and are likely to be reliable.
Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: a systematic review and meta-analysis. The review concluded that ultrasonography of optic nerve sheath diameter showed a good level of diagnostic accuracy for detecting intracranial hypertension in adult patients with traumatic brain injury and intracranial haemorrhage. The review was generally well conducted and the authors’ conclusions are based on the evidence and seem reasonable but the evidence base was small and lacked statistical power.