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.
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.
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.
Some statistical measures in evidence-based medicine, such as RRR, ARR and NNTwere introduced.
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.
In this paper, we introduce meaning and purpose of confidence interval (CI) in evidence-based medicine, For example, RRR ,ARR ,NNT. It s referance for user and doer of EBM in China.
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.
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.
Liver fibrosis in chronic liver disease refers to the body’s repair response to sustained repeated necrosis or inflammation of liver cells, which results in fibrosis accompanied by relative or absolute lack of fiber degradation and deposition of extracellular matrix in the liver. Early and timely diagnosis and treatment of hepatic fibrosis are of great importance to patients with liver disease. A rational and complete diagnostic model of liver fibrosis should involve clinical pathology and histology, imaging, and serum biochemical markers. Liver biopsy has been regarded as the "gold standard" for the diagnosis of liver fibrosis and as a reference standard for other non-invasive diagnostic tests of liver fibrosis. Since it is invasive, liver biopsy is difficult to implement in clinical practice and a second liver biopsy is even more difficult. As for the non-invasive diagnosis of liver fibrosis, clinical symptoms and signs are not specific. The sensitivity and specificity of individual serum biochemical markers are still very weak, and imaging studies also lack specificity. The mathematical model “FibroTest” of serum biochemical markers has better diagnostic accuracy, but the calculation is complicated, making it difficult to achieve widespread use. There is insufficient evidence to suggest that the "gold standard" of liver biopsy can be replaced. Therefore, further research is needed to investigate how best to balance the benefits and harms of different tests, to identify the best combination, to simplify any calculation steps, to reduce costs, to avoid liver biopsy, and to find new, more specific and sensitive markers.
To assess the rel iabil ity of diabetic cutaneous ulcer surface area (DCUSA) measurement usingdigital planimetry method (A) and transparency tracing method (B). Methods Images of diabetic cutaneous ulcers from35 inpatients with diabetic skin ulcers from September 2005 to April 2007 were taken by a digital camera once a week or twice a week over a period of 12 weeks, resulting in 305 photographs; the ulcers were traced on a grid with acetate wound tracings, simultaneously. A total of 305 pairs of DCUSA which were calculated respectively throughout digital camera combined with Image J medical imaging software and transparency tracing with grid sheet by two independent observers sequentially were obtained. The intraclass correlation coefficients (ICCs, one-way random effect model) was used as an indicator of chancecorrected agreement to estimate the relative rel iabil ity for the interobserver data. Multiple l inear regression analysis was also used to measure the relationship of these two methods. Results DCUSA obtained from method A and obtained from method B was (4.84 ± 7.73) cm2 and (5.03 ± 7.89) cm2, respectively; no significant difference was found (P gt; 0.05). ICCs was high (ICCs=0.949 for method B and 0.965 for method A), indicating that the relative rel iabil ity for the interobserver was excellent. The method A were highly correlated with measurements obtained from method B (r = 0.957, P lt; 0.05). Conclusion The digital planimetry method described in this study represents a simple, practical, without any wound damage and contamination, and inexpensive technique to accurately evaluate the areas of diabetic cutaneous ulcers. The photographic technique combined with Image J medical imaging software should be considered for wound measurement.