Through collecting and synthesizing the paper concerning the method of dealing with heterogeneity in the meta analysis, to introduce the multi-levels statistical models, such as meta regression and baseline risk effect model based on random effects, and random effects model based on hierarchical bayes, and to introduce their application of controlling the meta analysis heterogeneity. The multi-levels statistical model will decompose the single random error in the traditional model to data structure hierarchical. Its fitting effect can not only make the meta-analysis result more robust and reasonable, but also guide clinical issues through the interpretation of association variable.
Objective To assess the efficacy and safety of chewing gum in promoting bowel recovery after cesarean section. Methods Such databases as The Cochrane Library, MEDLINE, EMbase and CBM were searched from their establishment to 2010 to include the randomized controlled trials (RCTs) of comparing chewing gum with other procedures for promoting postoperative bowel function after cesarean section. The risks of bias in the included studies were evaluated at randomization, allocation concealment, blinding, completeness of outcomes, and selective reporting. Meta-analyses were performed by RevMan 5.0.22 software. Results Three RCTs involving 745 participants were included. The results of meta-analyses showed chewing gum after cesarean section significantly shortened the time before getting the first postoperative flatus (MD= –6.54, 95%CI –7.82 to –5.27, Plt;0.000 01), reduced the risks of postoperative ileus (RR=0.54, 95%CI 0.34 to 0.87, P=0.01) and possibly shortened the length of hospital stay (MD= –0.21, 95%CI –0.39 to –0.03, P=0.02) compared with blank control. Currently, no adequate data supported the safety of chewing gum after cesarean section. Conclusion Chewing gum after cesarean section can promote the postoperative bowel recovery, and reduce the odds of postoperative ileus. However, more high quality RCTs are required for lack of included studies and poor quality of methodology.
Objective To compare the ability of three propensity score weighting methods to balance the covariates and the advantages and disadvantages to estimate the treatment effects when dealing with multiple treatment data under different sample sizes. Methods Monte Carlo simulation was used to generate data sets and the advantages and disadvantages of balancing covariates and estimating the treatment effects of three propensity score weighting methods, Logistic-IPTW, Logistic-OW and GBM-OW were compared. The evaluation index of covariate equilibrium level was the absolute standard mean difference. The evaluation indexes of effect estimation included the point estimate of treatment effect, root mean square error and confidence interval coverage. Results Compared with Logistic-IPTW and Logistic-OW, GBM-OW was better in effect estimation and had a smaller root mean square error in five scenarios where covariates were related to treatment factors and outcome variables with different varying degrees of complexity. In terms of covariate equilibrium, all three methods had good effects. GBM-OW method performed better when the overlap of propensity score distribution of multiple treatment data was relatively low and covariables had increasingly complex nonlinear relationships with treatment factors and outcome variables. Conclusion When dealing with multiple treatment data, GBM-OW method has advantages over the other two methods when there is nonlinearity and/or interaction between covariates and treatment factors and outcome variables. Using this method, the effect estimation is closer to the real value, which is a better choice.
Objective To investigate the clinical effect of high intensity focused ultrasound (HIFU) and uterine artery embolization (UAE) in the treatment of cesarean scar pregnancy (CSP). Methods A total of 152 patients with CSP diagnosed by B-type ultrasonography were enrolled prospectively in this study from June 2014 to May 2016 in Chengdu Women and Children’s Central Hospital and Suining Central Hospital. Six patients from Chengdu Women and Children’s Central Hospital and 84 from Suining Central Hospital for Volunteered HIFU treatment were regarded as observation group. The other 62 patients from Chengdu Women and Children’s Central Hospital were selected to accept UAE treatment voluntarily were designated as control group. The clinical efficacy and therapeutic safety of the two groups were compared after the treatment. Results Eighty-two patients (91.1%) in the observation group and 32 (51.6%) in the control group had a bleeding volume equal to 100 mL or lower during complete curettage of uterine cavity (P<0.05). The hospitalization expenses of the above two groups were respectively (25 126.51±1 473.49) and (32 928.42 ±1 579.35) yuan (P<0.05). The hospitalization time was (11.03±1.52) and (10.65±1.87) days respectively, and the difference was not statistically significant (P>0.05). There was no significant difference in the normal rate of human chorionic gonadotropin recovery between the observation group and the control group at 14 days after treatment (P>0.05). Eighty-seven patients (96.7%) in the observation group and 51 (82.3%) in the control group had their menstrual recovery to normal level at 2 months after treatment, and the difference was statistically significant (P<0.05). The incidence of postoperative complications was 1.1% and 6.4% in the observation group and the control group, respectively, and the difference was not statistically significant (P>0.05). Conclusions HIFU in the treatment of CSP is safe and effective. Compared with UAE, HIFU requires less cost with fewer complications, which is worth promoting.
Objective To access and identify risk factors related to death and injuries in earthquakes. Method We searched The Cochrane Library, SCI, PubMed, CBM and CNKI from establishment to June 2008 to identify cohort, case-control and cross-sectional studies involving risk factors related to death and injuries in earthquakes. The methodological quality of included cohort and case-controlled studies were assessed, and the potential risk factors of earthquake related death and injuries were systematically enumerated. Results Two cohort, 2 case-control and 4 cross-sectional studies were included. Some included studies might be associated with selection bias. Risk factors for earthquake death and injuries included age, gender, mental disease, physical disabled, socioeconomics status, type/ age/ height/ collapse of building, motor vehicle driver and geographical location when the earthquake occurred. Conclusions Death and injuries in earthquakes may be attributed to 3 categories: demographic characteristics, building features, and seismic/ geographical/ location factors. However, the conclusion of this review and its implications may be limited by the potential selection bias of included studies and the regional characteristics of the included populations. Original studies from Chinese seismic areas are especially needed.
目的 比較5種新一代抗癲癇藥物對成人全面強直陣攣發作單藥治療的保留率。 方法 選擇2010年7月－2011年6月354例確診為癲癇全面強直陣攣發作患者，分別采用拉莫三嗪、左乙拉西坦、奧卡西平、托吡酯、加巴噴丁5種藥物進行單藥治療，對其5種藥物的6、12個月保留率進行比較。 結果 5種藥物的6、12個月保留率分別為：拉莫三嗪90.8%、79.8%，左乙拉西坦88.0%、66.7%，奧卡西平82.1%、58.2%，托吡酯81.2%、58.0%，加巴噴丁26.5%、20.6%。6個月保留率加巴噴丁與其他4種藥物比較差異有統計學意義（P＜0.001），其他藥物之間差異無統計學意義。12個月保留率拉莫三嗪與其他4種藥物比較差異有統計學意義（P＜0.005），其他藥物之間差異無統計學意義。 結論 拉莫三嗪對成人全面強直陣攣發作單藥治療12個月保留率最高。通過對5種新一代抗癲癇藥物12個月保留率比較研究，可以對臨床單藥治療癲癇藥物選擇提供一定參考。
Randomized controlled trials (RCTs) are often limited because of ethical or operational reasons. Quasi-experimental studies could be an alternative to RCTs to make causal inferences without randomization by controlling the confounding effects of the study. This paper introduced the general statistical analysis methods of quasi-experimental design through basic ideas, characteristics, limitations and applications in medicine, including difference-in-difference models, instrumental variables, regression discontinuity design, interrupted time series, and so on, and to provide references for future research.
Objective To assess the efficacy and safety of laparoscopic staging and surgery for patients with cervical cancer. Methods We searched The Cochrane Library, MEDLINE, EMbase, CBM (from inception to 2009). Randomized controlled trials (RCTs) were identified according to the inclusion and exclusion criteria, and then the quality of included trials was accessed, and the data were extracted. Meta-analysis was performed by RevMan 5.0.2 software. Results Two RCTs involving 120 participants were included. The results of meta-analyses showed laparoscopic surgery, compared with open surgery, shortened postoperative ileus time (MD= –18.20, 95%CI –22.20 to –14.20, Plt;0.001), reduced the postoperative pain (MD= –1.30, 95%CI –1.86, to –0.74, Plt;0.001) and shortened the overall hospital stay (MD= –1.30, 95%CI –1.59 to –1.01, Plt;0.001). Currently, no evidence supported the superiority of laparoscopic surgery on duration of surgery, number of harvested lymph node and intraoperative blood loss over open surgery. Moreover, the laparoscopic surgery neither increased nor decreased the risk of postoperative complications. Conclusion The laparoscopic staging and surgery could shorten the recovery time of gastrointestinal function, shorten hospital stay, reduce pain in patients, but have no advantages in postoperative complications, operative time, number of lymph node biopsy, and intraoperative blood loss, compared with open surgery. However, the evidence is not b enough because of the low quality of the included studies. Thus, more high-quality RCTs are required in future.
Objective To learn the current situation of traditional Chinese medicine (TCM) systematic reviews/meta-analyses published in Chinese journals. Methods All TCM systematic reviews/meta-analyses published from 1978 to July 31, 2009 were searched in the Chinese Biomedical Database (CBM). According to the inclusion and exclusion criteria, relevant information was extracted on the basis of research purpose. Meanwhile, publication year, journal name, author’s district, number of authors and their articles, types of diseases and interventions were took as the indexes, and then descriptive analysis was performed using SPSS 15.0 software. Results A total of 245 articles including 238 in Chinese and 7 in English were included. All of them were published in 117 different journals from 1998 to 2008, showing an accelerating growth trend of article number. In addition to only one article with first author from Germany, the first author of other 244 were from 24 domestic provinces (autonomous regions and municipalities); the number of authors ranged from 1 to 11; a total of 186 people had published articles as first author, and the number of their published articles ranged from 1 to 29. There were 16 types of diseases according to the International Classification of Diseases 10th Edition (ICD-10). Totally, 218 articles took drugs as interventions (including 106 listed drugs, 25 self-made prescriptions, 70 related to both listed drugs and self-made prescriptions, and 17 without reporting detailed interventions), accounting for 89%; and 27 articles were about non-drug interventions (including 26 about acupuncture and 1 about massage), accounting for 11%. Most (95.8%) of the articles about self-made prescriptions and listed drugs/self-made prescriptions adopted inappropriate pooled analyses. Conclusion Evidence-based medicine has been spread into the field of TCM, the number of TCM systematic reviews/meta-analyses shows an accelerated growth trend. The types of diseases discussed in the literature were almost the same as the diseases those could be effectively treated by TCM, but there existed imbalance in districts. In the future, systematic review/meta-analysis on drug intervention should aim at Chinese patent medicines and single medicines rather than self-made prescriptions, and should pay more attention to advantageous drugs and advantageous treatments of diseases. Moreover, importance should be also attached to clinical heterogeneity controlling when using acupuncture as a non-drug intervention.
Objective To elaborate on the statistical analysis methods for evaluating the accuracy of imaging diagnostic tests in a multiple-reader multiple-case (MRMC) design through formula derivation and real cases. Methods This study consisted of two parts: theoretical derivation and a real case study. The theoretical part discussed in detail the principles and procedures of MRMC statistical analysis methods, particularly the Obuchowski-Rockette (OR) and Dorfman-Berbaum-Metz (DBM) methods. The real case included 100 subjects, of whom 67 had disease. Four readers interpreted all the cases based on both traditional film imaging methods and digital imaging methods. OR and DBM methods were employed for data analysis. Results The real case showed that the OR and DBM methods had a high degree of consistency, with only slight differences in the confidence intervals. Conclusion It is recommended to use the OR and DBM methods for the statistical analysis of imaging diagnostic test accuracy, ensuring that the impact of reader factors on the evaluation results is fully considered. The results from the OR and DBM methods are relatively similar; when applying these methods in practice, one should consider the specific characteristics of the data and the research design to choose the appropriate analysis method. Besides, there are still challenges when applying the OR and DBM methods, such as software implementation and missing data handling, which require further exploration.