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.
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 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.
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.
目的 比较5种新一代抗癫痫药物对成人全面强直阵挛发作单药治疗的保留率。 方法 选择2010年7月－2011年6月354例确诊为癫痫全面强直阵挛发作患者，分别采用拉莫三嗪、左乙拉西坦、奥卡西平、托吡酯、加巴喷丁5种药物进行单药治疗，对其5种药物的6、12个月保留率进行比较。 结果 5种药物的6、12个月保留率分别为：拉莫三嗪90.8%、79.8%，左乙拉西坦88.0%、66.7%，奥卡西平82.1%、58.2%，托吡酯81.2%、58.0%，加巴喷丁26.5%、20.6%。6个月保留率加巴喷丁与其他4种药物比较差异有统计学意义（P＜0.001），其他药物之间差异无统计学意义。12个月保留率拉莫三嗪与其他4种药物比较差异有统计学意义（P＜0.005），其他药物之间差异无统计学意义。 结论 拉莫三嗪对成人全面强直阵挛发作单药治疗12个月保留率最高。通过对5种新一代抗癫痫药物12个月保留率比较研究，可以对临床单药治疗癫痫药物选择提供一定参考。
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.
ObjectiveTo explore two methods of sample size estimation in multi-reader multi-case study of radiological diagnostic test and realize them by software. MethodsDemonstration programs were conducted in R software using the Van Dyke dataset, calculating combinations of readers and cases using the OR and DBM methods. These serve as pilot test results for multi-reader multi-case studies, providing a reference for parameter settings in subsequent formal experiments. ResultsWhen the effect size was 0.044, 6 readers and 247 cases could yield 0.80 power, while with an effect size of 0.088, only 6 readers and 44 cases were needed to reach 80.5% power. The sample sizes calculated using the OR method and the DBM method were consistent, and the same sample size calculation results could be obtained through conversion between the two methods. ConclusionFor the estimation of sample size in multi-reader multi-case studies, R software provides a convenient and mature software package for sample size estimation using multi-reader multi-case designs in radiological diagnostic tests, thereby offering a reference for selecting appropriate sample size estimation and statistical analysis methods in radiological diagnostic tests.
The article aims to explore the optimal concentration of arsenic trioxide (As2O3) on HepG2 of liver cancer cells, and the effect of As2O3 on the migration, invasion and apoptosis of HepG2 cells. In this study, the activity of HepG2 cells treated with 0, 1, 2, 4, 8, 16, 32 μmol/L As2O3 was tested by CCK-8 method, the semi-inhibitory concentration (IC50) was calculated, and the morphological changes of HepG2 cells were observed after the action of As2O3 at IC50 concentration for 12, 24, 48 h. The effect of As2O3 on cell migration and invasion ability was verified by wound healing experiment and Transwell invasion experiment. Western blot and qRT-PCR were used to detect the effects of As2O3 on the gene and protein expression levels related to cell migration, invasion and apoptosis. The results showed that, compared with the control group, the activity of HepG2 cells decreased with the increase of the concentration of As2O3 treatment, showing a dose-dependent effect, and its IC50 was 7.3 μmol/L. After 24 hours’ treatment with 8 μmol/L As2O3, HepG2 cells underwent significant apoptosis, and its migration and invasion abilities were significantly reduced. In addition, the protein expression levels of RhoA, Cdc42, Rac1 and matrix metalloproteinase-9 (MMP-9) were down-regulated, the protein and mRNA expression levels of anti-apoptotic gene Bcl-2 were significantly down-regulated, and the protein and mRNA expression levels of pro-apoptotic genes Bax and Caspase-3 were significantly up-regulated. The above results indicate that certain concentration of As2O3 can inhibit the migration and invasion of hepatocellular carcinoma cells and promote the apoptosis of hepatocellular carcinoma cells.