Objective To investigate the phenotyping of COPD by cluster analysis and evaluate the value of this method.Methods 168 COPD patients were enrolled from Beijing Tongren Hospital. Demographic and clinical data, such as, sex, age, body mass index ( BMI) , smoking index, course of disease,exacerbation rate, and comorbidities were collected. Pulmonary function test, emphysema scoring by HRCT,dyspnea by MMRC score, COPD assessment test ( CAT) score, six-minute walk test were performed for each patient during the stable stage. Cluster analysis was conducted using SPSS 13. 0. Results According to the GOLD criteria,5, 75, 75, and 13 patients were classified into GOLD stage 1, 2, 3, and 4, respectively. There was no difference among different stages in sex distribution, BMI, smoking index, hypertension, and cerebral infarction incidence( P gt; 0. 05) , but the differences in age, disease course, dyspnea score, six-minute walk distance, BODE score, CAT score, coronary heart disease, exacerbation rate, and HRCT emphysema visual score were significant( P lt;0. 05) . By cluster analysis,168 patients were finally classified into three groups:younger/mild, older/ severe, and older/moderate. The patients with the same GOLD stage appeared indifferent clusters and the patients belonging to different GOLD stages could be in the same cluster. There were significant differences among three groups in age, BMI, exacerbation rate, dyspnea score, CAT score, and comorbidities. The result showed that HRCT emphysema visual score was also an important index todifferentiate clusters, suggesting that emphysema was an important phenotype of COPD. Conclusions Cluster analysis can classify homogeneous subjects into the same cluster, and heterogeneous subjects into different clusters. The results suggest that COPD phenotyping by cluster analysis is clinically useful and significant.
Epilepsy is a neurological disease with disordered brain network connectivity. It is important to analyze the brain network mechanism of epileptic seizure from the perspective of directed functional connectivity. In this paper, causal brain networks were constructed for different sub-bands of epileptic electroencephalogram (EEG) signals in interictal, preictal and ictal phases by directional transfer function method, and the information transmission pathway and dynamic change process of brain network under different conditions were analyzed. Finally, the dynamic changes of characteristic attributes of brain networks with different rhythms were analyzed. The results show that the topology of brain network changes from stochastic network to rule network during the three stage and the node connections of the whole brain network show a trend of gradual decline. The number of pathway connections between internal nodes of frontal, temporal and occipital regions increase. There are a lot of hub nodes with information outflow in the lesion region. The global efficiency in ictal stage of α, β and γ waves are significantly higher than in the interictal and the preictal stage. The clustering coefficients in preictal stage are higher than in the ictal stage and the clustering coefficients in ictal stage are higher than in the interictal stage. The clustering coefficients of frontal, temporal and parietal lobes are significantly increased. The results of this study indicate that the topological structure and characteristic properties of epileptic causal brain network can reflect the dynamic process of epileptic seizures. In the future, this study has important research value in the localization of epileptic focus and prediction of epileptic seizure.
Objective To learn the distribution pattern and worldwide research tendency of vitrectomy literatures. Methods Articles were searched from American Institute of Scientific Information (ISI) online database of web of science (WOS) database as a data source, to analyze the age distribution, national and regional, funding agency and citation of the vitrectomy literatures included during the year of 1971 -2011. The analysis software BibExcel and SPSS 19.0 were used to cluster highfrequency of them. Results Totally 8540 literatures were included, the numbers of them were gradually increased since 1971, significantly after 1991. The literatures were mainly in English, the literatures of our country capacity ranked 6th; funded institutions in all article, the National Natural Science Foundation of China ranked No. 5. Citation gradually increased since 1991, increased significantly after 2004. There were 50 highfrequency subjects, and hot topics were clustered into 6 categories which including vitrectomy for diseases of macula lutea, new techniques and complication of vitrectomy, medical treatment and surgical therapy of diabetic retinopathy, cataract, vitrectomy for endophthalmitis caused by intraocular injection and eye injury. Conclusions There is a growing trend on the research of vitrectomy. The hot topics include vitrectomy for diseases of macula lutea, new techniques and complication of vitrectomy. It may provide references for the scholars in scientific research and clinical studies.
Objective To investigate the hot topics of research on evidence-based medicine in 2002. Method To search MEDLINE for papers on evidence-based medicine published in 2002, identify high-frequency subject headings related to research on evidence-based medicine, and cluster the high-frequency subject headings according to rates they appeared in common papers. Results 545 papers, 1 554 subject headings, 30 high-frequency subject headings on evidence-based medicine, and nine clustering categories of high-frequency subject headings were identified through search. Conclusions Both high-frequency subject headings and their clustering categories suggested that “evidence-based practice guidelines and their innovation”, “evidence-based health research and health policy”, “methodology on systematic reviews and randomized clinical trials”, “method of evidence-based decision making and its application in various subjects”, were the hot topics of evidence-based medicine. They provided useful references for Chinese medical professionals to practice evidence-based medicine.
ObjectiveTo explore the current status and tendency of the application of CT or MRI in the pancreatic pseudocyst using bibiometric analysis for relative documents, and provide reference information for the future research of radiology. MethodsBibliographies from research literatures of CT or MRI application in the pancreatic pseudocyst from January 1, 2003 to September 20, 2014 in PubMed database were downloaded.The publication years, journals, the first authors, and the frequency of subject headings and subheadings were extracted from them by Bicomb 2.0 software.The subject headings and subheadings appeared more than five times were intercepted as high frequency ones, then created the high frequency subject headings and subheadings co-occurrence matrix.SPSS 22.0 statistical software was applied for clustering analysis with this matrix, then got the major hotspots. ResultsA total of 342 literatures were screened out.The research of CT or MRI application in the pancreatic pseudocyst increased slowly year by year in recent 10 years, then slowly decreased after 2008 year.The related literatures were published in the 164 journals, in which 16 journals (115 literatures were published) were core area distribution according to the Bradford law.There were 10 authors at least 2 published literatures, in who Bhasin DK in USA published 7 literatures, was the most active researcher in this field.The number of high frequency subject headings and subheadings was 33 and among which 5 research hotspots were clustered. ConclusionResearch hotspots about CT or MRI application in pancreatic pseudocyst mainly focuses on five aspects below:pathology, diagnosis, therapy, complications, and etiology.
ObjectiveTo systematically review the efficacy of exercise therapy for patients with chronic low back pain (CLBP) by network meta-analysis (NMA).MethodsThe PubMed, EBSCO, EMbase, The Cochrane Library, Web of Science, CNKI, WanFang Data, VIP and CBM databases were electronically searched to collect randomized controlled trials (RCT) on exercise for patients with CLBP from inception to May, 2020. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies. Then, NMA was performed by Stata 15.1 software.ResultsA total of 79 RCTs involving 5 782 CLBP patients were included. The effect of exercise therapy on pain in patients with CLBP were in the following rankings: yoga (SMD=−1.25, 95%CI −1.87 to −0.64, P<0.000 1), health Qigong/Taichi (SMD=−1.12, 95%CI −1.87 to −0.64, P=0.002), sling exercise (SMD=−1.07, 95%CI −1.64 to −0.50, P<0.000 1), Mackenzie therapy (SMD=−1.05, 95%CI −1.68 to −0.42, P=0.001), pilates (SMD=−0.96, 95%CI −1.74 to −1.78, P=0.016), multimodal training (SMD=−0.80, 95%CI −1.33 to −0.27, P=0.003) and stabilisation/motor control (SMD=−0.62, 95%CI −1.03 to −0.21, P=0.003). The effect of exercise therapy on function in patients with CLBP were in the following rankings: Mackenzie therapy (SMD=−0.62, 95%CI −1.03 to −0.21, P=0.003), and yoga (SMD=−0.88, 95%CI −1.51 to −0.25, P=0.007). Clusterank results showed that Mackenzie therapy, yoga, pilates, sling exercise and multimodal training were similar in improving pain and physical function in patients with CLBP.ConclusionsThe current study shows that yoga, Mackenzie therapy, pilates, sling exercise and multimodal training constitute the optimal group for improving CLBP symptoms. Health Qigong/Taichi is second only to yoga in improving pain in patients with CLBP, which has great promotional value.
ObjectiveTo analyze the current situation and international research focuses on the study of medical device risk management. MethodsTo retrieve medical device risk management literature information cited from 2002 to 2011 in PubMed such as high-frequency MeSH; analyze current situation and research focuses of medical device risk management by using bibliometrics, bibliographic item co-occurrence matrix builder (BICOMB), and graphical clustering toolkit (gCluto) for quantitative analysis, high-frequency MeSH term papers cluster visualization analysis. ResultsA total of 7 073 published studies were retrieved, basically suggesting a gradually increasing trend of the number of published papers. The top 3 numbers of first authors' papers referred to three countries: the United States, Britain and Germany, while China ranked twelfth. The top 3 numbers of journal articles referred to the United States, Britain and Holland, while China ranked twenty-second. Twenty journals published more than 50 papers, and all these journals were clinical journals. Thirty-three authors published no less than 5 papers, with the maximum of 18 articles. Totally, there were 124 highfrequency MeSHs. The high-frequency MeSHs were classified into 6 categories by using double cluster analysis: kinds 0 to 4 included risk report, risk analysis, risk assessment and methodology of heart valve prosthesis, coronary stents, peripheral vascular stents, implantable defibrillators and other life support device, surgical repair surgical flaps and minimal invasion surgical device such as laparoscopy; kind 5 focused on safety management, risk control, organization and implementation and other related research based on prevention and control of medical device adverse reaction, medical errors, occupation exposure, and equipment failure. ConclusionThe analysis on international literature on medical device risk management basically shows a gradually increasing trend; most studies published in the clinical medicine journals; research focus on risk assessment, safety management and quality improvement in the application such as angioplasty, artificial prosthesis replacement, plastic surgery, minimally invasive surgery and critical care medicine, and radiology diagnosis and treatment; implantable, life-supported invasive and radiological devices as the main research subject; and characteristics include closely combination between medical device risk management and the application of safe and effective, quality improvement systems for clinical diagnosis and treatment.
Objective To set up healthcare device-technology deployment assessment model and procedures through establishing the assessment parameter system between the functions of the clinical technical requirements and devices. Methods The bidirectional assessment parameter system developed by the literature review and Delphi, then combination weighting calculated by the combination weighting method, and the proposals for function deployment performed on the cluster analysis. Results The positive coefficients of twice Delphi were 75.56% and 87.50%, respectively. The effective recovery rates of the questionnaire were higher. The structure of the bidirectional assessment parameter system acquired according to the data mining and review, Delphi and integrated analysis. We calculated the weighting for the required functions and the deployed functions of the ventilator in the ICU, ER and RR. We listed the absolute importance and rank. The proposals for the function deployment of the ventilator which met different needs in fields of the critical care medicine were produced by the cluster analysis, ranking absolute importance and the calibration of weighting based on the investigation for actual function utilized rate. Conclusion It studies healthcare device-technology deployment assessment model by sequential integrated methods and sets up bidirectional assessment parameter system based on clinical technical function requirement, and the result is effective.
ObjectiveWhen using multi-center data to construct clinical prediction models, the independence assumption of data will be violated, and there is an obvious clustering effect among research objects. In order to fully consider the clustering effect, this study intends to compare the model performance of the random intercept logistic regression model (RI) and the fixed effects model (FEM) considering the clustering effect with the standard logistic regression model (SLR) and the random forest algorithm (RF) without considering the clustering effect under different scenarios. MethodsIn the process of forecasting model establishment, the prediction performance of different models at the center level was simulated when there were different degrees of clustering effects, including the difference of discrimination and calibration in different scenarios, and the change trend of this difference at different event rates was compared. ResultsAt the center level, different models, except RF, showed little difference in the discrimination of different scenarios under the clustering effect, and the mean of their C-index changed very little. When using multi-center highly clustered data for forecasting, the marginal forecasts (M.RI, SLR and RF) had calibrated intercepts slightly less than 0 compared with the conditional forecasts, which overestimated the average probability of prediction. RF performed well in intercept calibration under the condition of multi-center and large samples, which also reflected the advantage of machine learning algorithm for processing large sample data. When there were few multiple patients in the center, the FEM made conditional predictions, the calibrated intercept was greater than 0, and the predicted mean probability was underestimated. In addition, when the multi-center large sample data were used to develop the prediction model, the slopes of the three conditional forecasts (FEM, A.RI, C.RI) were well calibrated, while the calibrated slopes of the marginal forecasts (M.RI and SLR) were greater than 1, which led to the problem of underfitting, and the underfitting problem became more prominent with the increase in the central aggregation effect. In particular, when there were few centers and few patients, overfitting of the data could mask the difference in calibration performance between marginal and conditional forecasts. Finally, the lower the event rate the central clustering effect at the central level had a more pronounced impact on the forecasting performance of the different models. ConclusionThe highly clustered multi-center data are used to construct the model and apply it to the prediction in a specific environment. RI and FEM can be selected for conditional prediction when the number of centers is small or the difference between centers is large due to different incidence rates. When the number of hearts is large and the sample size is large, RI can be selected for conditional prediction or RF for edge prediction.
Objective To analyze and reveal the domestic and abroad studies on polypoidal choroidal vasculopathy (PCV) by bibliometric. Methods Foreign articles were searched from American Institute of Scientific Information online database of web of science (WOS) database, Chinese articles were searched from China National Knowledge Infrastructure (CNKI) database. The age distribution, national and regional, funding agency and citation of the PCV literatures published before December 31 2012 were analyzed by software Bibexcel and SPSS 17.0. Results Totally 696 literatures were analyzed, including 440 foreign literatures and 256 Chinese literatures. The numbers of foreign literatures were gradually increased since 2000, significantly after 2007, reached the maximum at 2011. The literatures were mainly in English, the number of the literatures of China ranked 4th of all countries. The National Natural Science Foundation of China ranked No.5 of funding agency. Citations gradually increased since 2000, increased significantly after 2008; there were 30 highfrequency subjects, and hot topics were clustered into 5 categories: treatment of PCV, genetics studies of PCV, detection, diagnosis and epidemiology of PCV, relationships between PCV and macular degeneration, related cytokine of PCV. Chinese literatures increased since 2000, significantly after 2006, and reached the maximum at 2010; there were 15 literatures supported by National Natural Science Foundation of China; Citation of Chinese literatures gradually increased since 2001, and reached the maximum at 2012. There were 30 highfrequency subjects, and hot topics were clustered into 5 categories: genetics and cytokine studies of PCV, detection and diagnosis of PCV, treatment of PCV, PCV and macular diseases, PCV and vitreous hemorrhage. Conclusions Literatures of PCV were gradually increased since 2000, abroad and domestic literatures of PCV reached maximum at 2011 and 2010 respectively. The abroad research of PCV focuses on 5 categories: treatment of PCV, genetics studies of PCV, detection, diagnosis and epidemiology of PCV, relationships between PCV and macular degeneration, related cytokine of PCV. The domestic research focuses on genetics and cytokine studies of PCV, detection and diagnosis of PCV, treatment of PCV, PCV and macular diseases, PCV and vitreous hemorrhage.