Epigenetic mechanisms influence gene expression and function without modification of the base sequence of DNA and may generateagenetic phenotype. Epigenetic modifications include DNA methylation, histone modifications, and deployment of noncoding RNA. There is growing evidence that epigenetic mechanisms could playacrucial role in the development of diabetic retinopathy (DR). Molecular biological methods which could maintain mitochondrial homeostasis through the regulation of epigenetic mechanisms may prevent the development of DR. Epigenetic-related treatment modalities will become the new direction of targeted therapy for DR.
Objective To evaluate the efficacy and safety of intravitreal bevacizumab (IVB) as a preoperative adjunct to vitrectomy for prevention of postoperative vitreous hemorrhage (VH) in proliferative diabetic retinopathy (PDR) patients.Methods This was a meta analysis of randomized controlled trials (RCT). A computerized search was conducted in the Medline, Embase, Cochrane Library, Chinese Biomedical Database and Chinese Journal Full text Database combined with manually searching of bibliographies of pertinent articles, journals and literature reference proceedings. RCT on IVB as a preoperative adjunct to vitrectomy for prevention of postoperative VH in PDR were selected according to inclusion and exclusion criteria. After the data extraction, methodological quality assessment of RCT that were included using the Jadad scale. The outcome measures included the incidence of postoperative VH, postoperative best corrected visual acuity (BCVA), the incidence of postoperative retinal reattachment and postoperative complications. The statistical analysis was performed by Stata/SE 11.2. The weighted mean difference (WMD) with 95% confidence interval (CI) was calculated for continuous variable, and odds ratio (OR) with 95% CI for dichotomous variable. Results In total, seven RCT that fulfilled the eligibility criteria were included in the metaanalysis involving 170 patients in IVB group and 161 patients in control group. According to the Jadad scale, one RCT scored 5 points, one RCT scored 3 points and the other 5 RCT scored 1 point. The results suggested that IVB group achieved lower incidence of postoperative VH than control group both within four weeks after surgery (OR=3.28, 95% CI: 1.58-6.82,P=0.00), and over four weeks after surgery (OR=2.51, 95% CI1.21-5.22,P=0.01). There was no significant differences in incidence of postoperative VH between IVB and control group either at postoperative 3 months (OR=2.52, 95% CI: 0.74-8.57,P=0.14), or at postoperative 6 months (OR=3.26, 95% CI: 0.50-21.45,P=0.22). The results suggested that IVB group achieved better postoperative BCVA than control group (WM1=0.29, 95% CI: 0.13-0.44,P=0.00), but no significant differences were found between IVB and control group on the incidence of postoperative retinal reattachment (OR=0.39, 95% CI:0.10ndash;1.59,P=0.19), postoperative retinal re-detachment (OR=2.36, 95% CI: 0.74- 7.56, P=0.15) and postoperative neovascular glaucoma (OR=1.47, 95% CI: 0.28ndash;7.71,P=0.65). Conclusions IVB as a preoperative adjunct to vitrectomy could prevent postoperative VH in PDR effectively, and be relatively safe. However, a high-quality, multicenter, large sample, long-term RCT is warranted to be further investigated.
In the process of guideline development and construction of clinical questions, it is necessary to guide clinicians to propose clinical problems into PICO (population, intervention, control, outcome) structured clinical questions. However, there are still unclear criteria to define and judge the appropriateness of the width of the PICO elements of a clinical question. Either too wide or too narrow can make the PICO question unsuitable to be a question for clinical practice guidelines to answer. We graded the clinical questions to be eight grades (3, 2, 1, 0, −1, −2, −3, mixed) according to the number of the PIC elements, which obviously needed to be adjusted to evaluate applicability of the appropriateness of the width of the clinical questions. Our work can provide methodological references for clinicians and guideline developers.
ObjectivesTo explore the characteristics of Chinese methodological studies on patient compliance in clinical trials so as to provide reference for clinical trial of patient compliance in future.MethodsCNKI, VIP, CBM and WanFang Data databases were electronically searched to collect methodological studies on patient compliance in clinical trials published in Chinese language from January 2000 to December 2018. Two reviewers independently screened literature, extracted data and then, qualitative analysis of document characteristics was then performed.ResultsA total of 84 articles were included, in which 68 were studies on Western medicine and 16 were studies on traditional Chinese medicine (TCM). The results showed that: the quantity of studies on patient compliance increased along with time. However, those in TCM field did not increase. All included studies summarized their strategies to improve patient compliance, however key information for quality evaluation were missing.ConclusionsThere is still a lack of research on how to improve patients’ compliance in clinical trials to ensure the reliability of the results. Existing studies have not systematically and comprehensively explored the influencing factors of patients’ compliance. Clinical trials researchers in China have not focused sufficiently to patients’ compliance and lack the proper methodology to frame studies.
ObjectivesTo explore the characteristics of the international clinical studies using objective performance criteria (OPC) and provide a reference to design clinical trials and determine external controls.MethodsPubMed, The Cochrane Library and EMbase databases were searched for all clinical studies which used OPC. Two reviewers independently screened literature, extracted data and descriptive analysis was then performed.ResultsA total of 51 English language articles were included. Merely one was published in 2001, and others were published between 2010 and 2018. Twenty-seven articles (27/51, 52.9%) were published between 2017 and 2018, with accumulated impact factors of 411. In the article referring to the reasons for using the objective performance criteria, reasons for using OPC study was primarily the difficulties of randomization and comparison (8/11, 72.7%). Articles with cardiovascular disease and peripheral vascular disease accounted for 86%, and articles on the effectiveness or safety of medical devices accounted for 76.5%. Single-arm trial (40), randomized controlled trials (2), case-control studies (2), case series (5) and diagnostic tests (2) were included. OPCs were mostly derived from the data of clinical trials of other similar products, national standards, specialist association standard and meta-analysis of multiple clinical studies. A total of 27 articles (27/51, 52.9%) used hypothesis testing to compare research results with objective performance goal, and 24 articles (24/51, 47.1%) used the confidence interval method.ConclusionsOPC studies are primarily used for safety intervention and effect evaluation. OPC studies are developing very rapidly, especially in the field of cardiovascular studies. Methodological details are reported reasonably sufficient. Reasons for using OPC study are primarily the difficulties of randomization and comparison. Factors such as source of the OPC, sample size, and comparison method should be taken into account. The application of the OPC can not only solve the difficulties of the implementation of numerous clinical research, but also provide new insights for solving the practical difficulties of clinical research in the real-world.