The results of clinical studies are usually described with statistical data. When we conduct systematic reviews of clinical studies it is important that the statistical methods used in the original research are evaluated. By doing so, we can assess the validity and reliability of the evidence.
This article systematically reviews the series of articles on randomized controlled trial (RCT) methodology guidance published in JAMA Surgery between 2022 and 2023. It focuses on providing an overview and guidance on critical aspects such as trial implementation and oversight, participant recruitment, statistical applications, and key points in manuscript publication. The aim is to offer valuable insights and references for surgeons to conduct efficient clinical trials and successfully publish their research findings.
Objective To establish a risk prediction model of diabetic retinopathy (DR) for type 2 diabetic patients (T2DM). Methods A total of 315 T2DM patients (600 eyes) were enrolled in the study. There were 132 males (264 eyes) and 183 females (366 eyes). The mean age was (67.28±12.17) years and the mean diabetes duration was (10.86±7.81) years. The subjects were randomly assigned to model group and check group, each had 252 patients (504 eyes) and 63 patients (126 eyes) respectively. Some basic information including gender, age, education degree and diabetes duration were collected. The probable risk factors of DR including height, weight, blood pressure, fasting glucose, glycosylated hemoglobin (HbA1c), blood urea, serum creatinine, uric acid, triglyceride, total cholesterol, high-density lipoprotein, low density lipoprotein cholesterol and urinary protein. The fundus photograph and the axial length were measured. Multivariate logistic regression was used to analyze the correlative factors of DR and establish the regression equation (risk model). Receiver operating characteristic (ROC) curves were used to determine the cut-off point for the score. The maximum Youden Index was used to determine the threshold of the equation. The check group was used to check the feasibility of the predictive model. Results Among 504 eyes in the model group, 170 eyes were DR and 334 eyes were not. Among 126 eyes in the check group, 45 eyes were DR and 81 eyes were not. Multivariate logistic regression analysis revealed that axial length [β=–0.196, odds ratio (OR)=0.822,P＜0.001], age (β=-0.079,OR=0.924,P＜0.001), diabetes duration (β=0.048,OR=1.049,P=0.001), HbA1c (β=0.184,OR=1.202,P=0.020), urinary protein (β=1.298,OR=3.661,P＜0.001) were correlated with DR significantly and the simplified calculation of the score of DR were as follows:P=7.018–0.196X1–0.079X2+0.048X3+0.148X4+1.298X5 (X1= axial length, X2=age, X3=diabetes duration, X4=glycosylated hemoglobin, X5= urinary protein). The area under the ROC curve for the score DR was 0.800 and the cut-off point of the score was -1.485. The elements of the check group were substituted into the equation to calculate the scores and the scores were compared with the diagnostic threshold to ensure the patients in high-risk of DR. The result of the score showed 84% sensitivity and 59% specificity. ROC curve for the score to predict DR was 0.756. Conclusion Axial length, age, diabetes duration, HbA1c and urinary protein have significant correlation with DR. The sensitivity and specificity of the risk model to predict DR are 84.0% and 59.0% respectively. The area under the ROC curve was 0.756.
Objective To clarify the most important factors affecting the survival of patient with gastric carcinoma. Methods 428 cases of resected gastric carcinoma were studied by using univariate analyses and multivariate regression analyses. Results The most significant factors influencing survival of these patients were peritoneal dissemination, Borrmann classification, type of operation, hepatic metastasis, size of tumor, location, lymph node metastasis and age. Conclusion The factors influencing survival in patient with gastric carcinoma after resection can be correctly analyzed by cox’s proportional hazard model.
Objective To investigate the specific variables and influence factors of Harris scores in follow-up data of patients with internal fixation of femoral neck fracture. Methods From May 1999 to May 2004, 99 cases of femoral neck fracture receiving close reduction with cannulated screw and having complete follow-up data were evaluated in terms of age, sex, type of bone fracture (Garden classification), reduction time, reduction qual ity (Garden indicators), time of full weight-loading, removal of internal fixation, traction before operation, side of bone fracture, necrosis of femoral head, duration of follow-up and Harris score during follow-up period. Univariate and multivariate were analyzed by SPSS14.0 and SAS8.2. Results P-P probabil ity plot and normal test revealed the Harris scores were non-normal distribution (W=0.757 09, P=0.000 1). By nonparametric test in univatiate analysis, the following variables in Harris scores were of statistic significance: the time of reduction (U=— 2.289, P=0.022), the Garden classifaction (H=16.943, P=0.001), the time of full weight-bearing (U=— 3.069, P=0.002), the qual ity of reduction (U=— 3.448, P=0.001) and the necrosis of femoral head (U=— 4.723, P=0.000).By the analysis of correlation, the following variables in Harris scores were of statistic significance: Garden classification(rs=— 0.412, P=0.000), the time of reduction (rs=— 0.231, P=0.021), the qual ity of reduction (rs=— 0.348, P=0.000), the time of full weight-bearing (rs=— 0.310, P=0.002), and the necrosis of femoral head (rs=— 0.477, P=0.000). By the univariate logistic regression analysis, the following variables in Harris scores were of statistic significance: Garden classification (P=0.000 1), the time of reduction (P=0.012 6), the qual ity of reduction (P=0.000 3), the time of full weight-bearing (P=0.003 2), the traction before operation (P=0.049 2) and the necrosis of femoral head (P=0.000 1). By the multivariate logistic regression analysis, the influence factors of Harris scores rank included the necrosis of femoral head (P=0.000 1), the time of reduction (P=0.028 2), and Garden classification (P=0.000 7). Conclusion Harris scores is of non-normal distribution, and the necrosis of femoral head is the most important factor influencing the function after applying internal fixation with cannulated screws to femoral neck fracture.
Objective To evaluate the quality of clinical studies on dentistry from the Chinese Journals. Methods Clinical studies in Chinese Journal of Conservative Dentistry of 2002 were searched. The quality of the clinical studies on assessment of treatments’ efficacy was evaluated. Results Among 204 related studies from 12 issues, there were 93 (45.58%) restrospective intervention studies, 6 randomized controlled blinded trials (2.94%), 42 randomized trials without blindness (20.58%), 20 controlled trials without randomization (9.80%) and 25 clinical observational studies (12.25%). The statistical analysis showed that 20 studies were with inappropriate methods. Conclusions It is necessary to improve the design and statistical analysis of clinical studies on stomatology in China to produce high-quality research evidence.