Predictive value of cystatin C level for contrast-induced acute kidney injury and poor long-term outcomes after cardiac catheterization / 实用医学杂志

Objective To investigate the predictive value of preprocedural cystatin C level for contrast-in-duced acute kidney injury (CI-AKI) and poor long-term outcome after cardiac catheterization. Methods One thou-sand one hundred and fifty-four patients underwent cardiac catheterization were enrolled in Guangdong general hos-pital. The level of serum cystatin C was determined at 24 hours pre-operation. A 2-year follow up was performed for each patient. Preprocedural cystatin C level was compared between patients with or without CI-AKI. The cystatin C quartiles were compared between patients with incidence of CI-AKI and patients with adverse in-hospital outcomes. Analyses of the receiver operating characteristic curves (ROC) were performed to evaluate the predictive value and cutoff level of cystatin C level for CI-AKI. The log-rank test and Cox regression analyses were also performed to in-vestigate the correlation between cystatin C level and poor long-term outcomes. Results CI-AKI occurred in 42 patients (3.6%). The cystatin C level was significantly higher in the CI-AKI group than that in the non-CI-AKI gu-oup (1.76 ± 1.05 vs 1.20 ± 0.50 mg/L, P=0.001). Patients with higher cystatin C level also had higher risk of CI-AKI and adverse in-hospital outcomes. ROC and Youden index showed that 1.3 mg/L cystatin C of was a fair dis-criminator for CI-AKI, but not significantly different from the Mehran CI-AKI score (AUC, 0.75 vs 0.76, P =0.874). After adjusting for other known CI-AKI risk factors, cystatin C level over 1.3 mg/L remained significantly associated with CI-AKI. During the long-term follow-up , the patients with cystatin C level over 1.3 mg/L were at a higher risk of all-cause mortality and MACEs (P < 0.001). Concusions A preprocedural cystatin C level over 1.3 mg/L was a good predictor of CI-AKI and poor long-term outcomes after cardiac catheterization.

Statistical methods for comparing survival rates at a fixed time point / 中华流行病学杂志

Comparison of survival curves between two groups is an important part of disease prognosis study.Log-rank test is commonly used,but when the two curves' later intersecting opening is too large,the proportion of assumptions is not established,thus the Log-rank test is ineffective.We introduces five statistical tests to compare two survival curves at a fixed time points:classic method,logarithmic transformation,cloglog transformation,arcsine transformation and logit transformation.Through the study we found that if the overall survival curves are difficult to compare between groups tested with Log-rank test method or Two-stage test method,the fixed time point test can effectively determine whether there was significant difference in survival rate at a fixed time point.Among the five fixed time point tests,cloglog transformation could give more precise result.

Development and application of automatic dental crown remover / 医疗卫生装备

Objective To develop a dental crown remover with the strength provided constantly and adjusted freely.Methods The remover was composed of a shell, a crown hook, a conduction mechanism, a strength generating mechanism and a percussion mechanism. The spring had the explosive force formed in the crown head to destruct the cohesion of the cement.Results The remover could remove the crown, with one hand freed for the protection of abutment and mucous membrane.Conclusion The remover has simple structure and easy operation, and is worth popularizing clinically.