Objective To evaluate the effects of intraocular lenses (IOL) of silicone and polymethylmethacrylate (PMMA) on posterior capsule opacification (PCO). Methods We searched MEDLINE (1966 to 2003), EMBASE (1980 to 2003), Cochrane Central Register of Controlled Trials (Issue 1, 2003) and CBMdisc (1979 to 2003). Only randomized controlled trials (RCTs) were identified. Two reviewers independently assessed the quality of the included trial and extracted data. The following outcomes were assessed: PCO index, percentage of neodymium: YAG (Nd: YAG) laser posterior capsulotomy and visual acuity after cataract surgery. RevMan 4.2 was used for meta-analysis.Results Nine RCTs including 672 eyes were included. In patients with senile cataract, the results of meta-analysis suggested that silicone lens were better than PMMA lens on PCO index (the pooled SMD=－0.92, 95%CI －1.19 to －0.64) and percentage of Nd: YAG (the pooled OR 0.35, 95%CI 0.22 to 0.57) with a statistically significant difference, but there was no significant difference on visual acuity (the pooled OR 1.22, 95%CI 0.43 to 3.50) after cataract surgery between silicone lens and PMMA lens. However, in patients with uveitic cataract, the results of meta-analysis showed that PMMA lens were better than silicone lens in visual acuity (the pooled OR 0.38, 95%CI 0.15 to 0.91) after cataract surgery with a statistically significant difference, but there was no significant difference on PCO index (SMD 0.23, 95%CI －0.59 to 1.05) and percentage of Nd: YAG (the pooled OR 1.82, 95%CI 0.47 to 6.95) between silicone lens and PMMA lens. Conclusions Current evidence indicates that silicone lens are superior to PMMA lens in reducing PCO. Further trials with high quality on methodology are required.
Scientific and rigorous study design could improve the reliability of results of the comparative diagnostic test accuracy studies. The design procedures of a comparative diagnostic test accuracy study included: constructing the clinical questions, identifying the appropriate gold standard, selecting the representative patient sample, calculating the sample size, blindly interpreting and comparing the results of diagnostic tests, and setting up the cut-off value. This paper introduced 5 categories of the designs of comparative diagnostic test accuracy studies: fully paired, partially paired with a random subset, partially paired with a nonrandom subset, unpaired randomized, and unpaired nonrandomized design.
Comparative diagnostic test accuracy study, a type of diagnostic accuracy test, aims to compare accuracy of two or more index tests in a study. The application of GRADE in comparative test accuracy differs from single test accuracy, mainly including the selection of appropriate comparative study designs, additional criteria for judging risk of bias, and the consequences of using comparative measures of test accuracy. The study focuses on basic principles and methods of GRADE approach in systematic reviews of comparative test accuracy to promote the understanding and application of the method by domestic scholars.
ObjectivesTo systematically review the methodological and reporting quality of the current global breast cancer screening guidelines so as to provide useful information for domestic study in the future.MethodsWe searched databases including PubMed, The Cochrane Library, Web of Science, EMbase, CNKI, CBM, WanFang Data and some cancer official websites to collect breast cancer screening guidelines from inception to February, 2018. Two reviewers independently screened literature, extracted data and assessed the quality of the guidelines by using AGREE II tool and RIGHT statement.ResultsA total of 11 guidelines were included, in which 5 guidelines (45%) were issued by the USA. The results of the quality assessment showed that: the average scores in the " scale and objective”, " participants”, " rigorism”, " clarity”, " application”, and " independence” of all guidelines were 83, 48, 60, 77, 53 and 79, respectively. 6 guidelines were evaluated as level A and 5 as level B. For the reporting quality, 3 guidelines were of high quality, including 2 in the USA and 1 in Canada.ConclusionsThe methodological and reporting quality of breast cancer screening guidelines are at present very satisfactory. The quantity of clinical guidelines shows an increasing trend. Multi-country contribution to one guideline is another trend. The evidence-based methodology has been accepted globally in the guideline development.
By comparing the diagnostic accuracy of two or more tests in the same study, the one with the higher diagnostic accuracy can be screened. Therefore, it is extremely important to conduct the comparative diagnostic test accuracy study. This paper introduced the concept of the comparative diagnostic test accuracy study, compared it with single diagnostic test accuracy study, and described its role, study design, statistical analysis, current status, and challenges.
The correct and reasonable statistical analysis method can make the results of comparative diagnosis test accuracy more convincing. In this paper, the accuracy of diagnostic tests is divided into 2 forms: binary-scale outcomes and ordinal-scale/continuous-scale outcomes. Taking diagnostic indicators such as sensitivity, specificity, receiver operating characteristic (ROC) curves and area under curve (AUC) values as entry points, combined with examples, this paper introduced how to compare the diagnostic results of tests by parameter estimation and hypothesis testing, with the aim of providing references for the comparative diagnosis test accuracy.