In this paper, we introduce theory and practice method about combining independent studies of Diagnostic test into a summary ROC curve. This is a useful and easily applied by clinicians to analyse the data of diagnostic test. It’s referance for user and doer of EBM in China.
A mean of systematic review of diagnostic tests based on The Bayes Library of Diagnostic Studies and Reviews (2nd edition 2002) and Bayes Library are introduced to Chinese readers who are interesting on diagnostic test and screening systematic review.
Objective To evaluate the effectiveness and safety of intraluminal brachytherapy (ILBT) in prolonging survival and the period free of symptoms for patients with unresectable bile duct cancer. Methods We searched MEDLINE (1977 to May 2007), CNKI (1979 to May 2007) and CBM Disk (1979 to May 2007). The qual ity of included studies was assessed according to the guidance in the Cochrane Handbook for Systematic Reviews of Interventions. Results One randomized controlled trial involving 42 patients with unresectable bile duct cancer fulfilled the inclusion criteria. This found that the median survival time was longer for patients treated with endoprostheses and ILBT compared to those treated with endoprostheses alone (387.9 days versus 298.0 days, Plt;0.05). The stent patency time in patients who were treated with endoprostheses and ILBT was longer than for those treated with endoprostheses alone (378.4 days versus 245.5 days, Plt;0.01). The reductions in bil irubin (mol/l) and alkal ine phosphatase (kat/l) before and after drainage in patients who were treated with endoprostheses and ILBT were similar to those treated with endoprostheses alone (Mean ±SD of bil irubin: before: 219.3 ± 40.5, after: 23.1 ± 37.1 versus before: 227.3 ± 39.8, after: 22.5 ± 44.2; Mean ± SD of alkal ine phosphatase: before: 10.3 ± 5.1. after: 3.6 ± 2.9 versus before: 11.7 ± 5.8, after: 3.7 ± 2.9). No severe adverse effects were observed in the trial. Conclusion Current evidence suggests that ILBT for unresectable bile duct cancer may improve the survival time of patients, prolong the time they spend symptom free, improve their quality of l ife and reduce the burden of treatment. However, it may increase toxicity in normal tissues, which can be managed by adjusting radiation dosage. No serious adverse effects were observed in the 42 patients in the trial in this review. More randomized controlled trials with large sample size are needed to provide rel iable results.
The original meaning of “allocation concealment” is that the statistician and the trial designer who generated the random sequence and allocation sequence should not recruit and allocate the participants for the purpose of avoiding selection bias. In the process of generating allocation sequence, combined blinding measures are so called “setting blinding”, for instance, by using “double simulation”. We use a example to describe how to perform an adequate allocation and conceal the sequence, and setting blinding. Another example is used to describe how to report the methods of randomization, allocation concealment and the effect of blinding, etc.
In 1993 the Cochrane Collaboration, an international non-profit organization aiming at producing, updating and disseminating systematic reviews, was founded. Several years later, in 1999, the Chinese Cochrane centre opened in Chengdu, to provide support to (1) Chinese researchers willing to produce reviews and (2) politicians and practitioners willing to start using the results in daily practice. We searched PubMed and the database of the Chinese Cochrane Centre to retrieve data on the overall number of articles and reviews produced in the Chinese language for the period 1990 to 2006. Although the number of reviews increased substantially since the year 2000, the percentage of reviews in the overall number of articles indexed in PubMed remains modest.
NNT defines the number of patients who need to be treated in order to achieve one additional favorable outcome, and NNH is defined as the number of patients who must be treated with a therapy in order to have one additional patient suffer an adverse effect compared with the control treatment. This is the most important thing that should beconsidered before administering a treatment. NNT can also be used to assess the relative benefit or harm in the comparison of intervention versus positive control. If the effect is smaller in the intervention group than that in the control group, NNT should be used; if the effect is bigger in the intervention group than that in the control group, NNH should be used. When comparison is made between an intervention versus placebo, NNT and NNH are absolute outcomes; when an intervention is compared to a positive control, NNT and NNH are relative outcomes. RR or OR or RD may help to judge which comparator has bigger or smaller effect, and whether NNT or NNH should be used.
Objective To evaluate the accuracy and quality of diagnostic test of Electrochemiluminescence immunoassay (ECLIA) in detecting A-fetal protein (AFP) for the diagnosis of liver cancer in Chinese patients. Methods We searched Chinese Biological Medicine Database (CBM, 1978 to 2005) and China National Knowledge Infrastructure (CNKI, 1994 to 2005). Diagnostic tests of ECLIA in detecting AFP for the diagnosis of liver cancer were included. Data were extracted, and the quality of included studies was evaluated according to the six criteria of diagnostic tests. Results Forty-eight studies were identified, but only 6 were included and none mentioned the indices about the accuracy. Conclusion The number of studies of ECLIA in detecting AFP for the diagnosis of liver caner is few and the quality is poor. We cannot draw the conclusion that ECLIA is better for sensitivity and specificity.
We described our understanding of EBM, the ‘three principles＇ and ‘five steps＇ to practice it. EBM is an embodiment of human moral rule and axiom in clinical medicine; it is an advanced clinical model and medical practical methodology; it results from a basis of developed and perfected clinical research methodology, best evidence database, information technology. We also discussed the relationship between EBM and traditional Chinese medicine （TCM） modernization. The definition of modernization of TCM was suggested as scientifical standardization and internationalization. TCM theory in fact is not a basic but a clinical practice theory. EBM model should become the standard model of TCM practice to accelarate the standardization of TCM diagnostic technique and therapy. The key is not try to explain TCM theories with modern medical theroies, but work out common effectiveness evaluation criteria. Only when the effectiveness is intemationally acknowledged, can TCM be internationalized.
In this paper , the statistic significance and clinical application of forest plots in a meta-analysis have been fully discussed. If the horizontal line represents the 95% confidence interval of the indexes including odds ratio, relative risk, weighted mean difference, and standard mean difference crosses the vertical line, the effect of test group is not signficant with that of control group; if the horizontal line lies to the right of the vertical line, it indicates that the test group is significantly effctive. If the horizontal line lies to the left of the vertical line, it indicates that the control group is more effective. In addition, it doesn’t mean that clinical application is more beneficial, if the treatment study has more effect, because experimental factor can be positive or negative.
While proposing evidence-based medical decision, we analyzed the existing problems in laboratory medicine, discussed the necessity and probability and explored the practicing way of evidence-based laboratory medicine, in order to follow the latest developing of clinical medicine and provide the best clinical laboratory technique and clinical laboratory service for good patient care.