Using a monotone single-index model to stabilize the propensity score in missing data problems and causal inference

The augmented inverse weighting method is one of the most popular methods for estimating the mean of the response in causal inference and missing data problems. An important component of this method is the propensity score. Popular parametric models for the propensity score include the logistic, probit, and complementary log-log models. A common feature of these models is that the propensity score is a monotonic function of a linear combination of the explanatory variables. To avoid the need to choose a model, we model the propensity score via a semiparametric single-index model, in which the score is an unknown monotonic nondecreasing function of the given single index. Under this new model, the augmented inverse weighting estimator (AIWE) of the mean of the response is asymptotically linear, semiparametrically efficient, and more robust than existing estimators. Moreover, we have made a surprising observation. The inverse probability weighting and AIWEs based on a correctly specified parametric model may have worse performance than their counterparts based on a nonparametric model. A heuristic explanation of this phenomenon is provided. A real-data example is used to illustrate the proposed methods.     

The association between body mass index and in-hospital outcome among patients with acute myocardial infarction—Insights from China Acute Myocardial Infarction (CAMI) registry

BackgroundThe relationship between body mass index (BMI) and in-hospital mortality risk among patients with acute myocardial infarction (AMI) remains controversial.Methods and ResultsWe included 35,964 patients diagnosed with AMI in China Acute Myocardial Infarction registry between January 2013 and December 2016. Patients were categorized into 4 groups according to BMI level: BMI <18.5, 18.5–24.9, 25–30, and ≥30 kg/m² for underweight, normal, overweight, and obese groups, respectively. Clinical data were extracted for each patient, and multivariable logistic regression analysis was used to examine the association between BMI level and in-hospital mortality. Compared with normal-weight patients, obese patients were younger, more often current smokers, and more likely to have hypertension, hyperlipidemia, and diabetes. Multivariable regression analysis results demonstrated that compared with normal group, underweight group had significantly higher in-hospital mortality (odds ratio [OR]: 1.34; 95% confidence interval [CI]: 1.06–1.69; p = 0.016), while overweight group (OR: 0.86; 95% CI: 0.77–0.97; p = 0.011) and obese group (OR: 0.65; 95% CI: 0.46–0.91; p = 0.013) had lower mortality. All subgroups showed a trend toward lower in-hospital mortality risk as BMI increased.ConclusionsOur study provided robust evidence supporting “obesity paradox” in a contemporary large-scale cohort of patients with AMI and demonstrated that increased BMI was independently associated with lower in-hospital mortality.     

手术室医辅人员任务智能分配的抢单模式管理

目的研发适用于手术室医辅人员任务分配管理的智能软件信息系统,并探讨其运行效果。方法将2018年3月试运行抢单信息系统的509台次手术设为实验组,对医辅人员运用抢单模式进行管理;对同期未实施的486台次同类手术设为对照组,运用常规管理模式;比较两组的运行效果。结果实验组应答时间和完成任务时间显著短于对照组,护士满意率显著提升(均P0.01)。结论抢单信息系统精准记录了医辅人员的工作量和时间节点,提高了工作效率和护理人员满意率,促进了后勤医辅人员的科学化、精细化管理。     

重症患者再喂养综合征危险因素的Meta分析

目的 分析重症患者营养支持期间发生再喂养综合征的危险因素，为早期识别及预防再喂养综合征提供参考。方法 检索中国知网、万方数据库、中华医学期刊全文数据库、中国生物医学文献数据库、维普网、PubMed、Embase、Cochrane Library、Elsevier关于重症患者再喂养综合征危险因素的文献，检索时间为各数据库建库至2021年12月，采用RevMan5.3进行Meta分析。结果 纳入13篇文献，包括2 519例患者，其中病例组793例，对照组1 726例；Meta分析合并效应值显示年龄(WMD=4.69)、APACHEⅡ评分(WMD=2.50)、BMI(WMD=-0.94)、白蛋白水平(OR=4.61)、前白蛋白水平(WMD=-53.46)、基线血镁水平(WMD=-0.05)、基线血钾水平(WMD=0.18)、基线血磷水平(WMD=-0.07)是重症患者发生再喂养综合征的危险因素(P<0.05,P<0.01)。结论 基于现有证据，重症患者再喂养综合征的危险因素包括年龄、APACHEⅡ评分、营养状况及电解质水平，医护人员需密切关注重症患者营养支持期间能量、蛋白质及电解...     

Apelin-13 inhibits apoptosis and excessive autophagy in cerebral ischemia/reperfusion injury

Apelin-13 is a novel endogenous ligand for an angiotensin-like orphan G-protein coupled receptor, and it may be neuroprotective against cerebral ischemia injury. However, the precise mechanisms of the effects of apelin-13 remain to be elucidated. To investigate the effects of apelin-13 on apoptosis and autophagy in models of cerebral ischemia/reperfusion injury, a rat model was established by middle cerebral artery occlusion. Apelin-13(50 μg/kg) was injected into the right ventricle as a treatment. In addition, an SH-SY5 Y cell model was established by oxygen-glucose deprivation/reperfusion, with cells first cultured in sugar-free medium with 95% N2 and 5% CO2 for 4 hours and then cultured in a normal environment with sugar-containing medium for 5 hours. This SH-SY5 Y cell model was treated with 10–7 M apelin-13 for 5 hours. Results showed that apelin-13 protected against cerebral ischemia/reperfusion injury. Apelin-13 treatment alleviated neuronal apoptosis by increasing the ratio of Bcl-2/Bax and significantly decreasing cleaved caspase-3 expression. In addition, apelin-13 significantly inhibited excessive autophagy by regulating the expression of LC3 B, p62, and Beclin1. Furthermore, the expression of Bcl-2 and the phosphatidylinositol-3-kinase(PI3 K)/Akt/mammalian target of rapamycin(mTOR) pathway was markedly increased. Both LY294002(20 μM) and rapamycin(500 nM), which are inhibitors of the PI3 K/Akt/mTOR pathway, significantly attenuated the inhibition of autophagy and apoptosis caused by apelin-13. In conclusion, the findings of the present study suggest that Bcl-2 upregulation and mTOR signaling pathway activation lead to the inhibition of apoptosis and excessive autophagy. These effects are involved in apelin-13-induced neuroprotection against cerebral ischemia/reperfusion injury, both in vivo and in vitro. The study was approved by the Animal Ethical and Welfare Committee of Jining Medical University, China(approval No. 2018-JS-001) in February 2018.     

关节镜下经髌腱入路空心拉力螺钉复位固定治疗胫骨髁间嵴撕脱骨折*

目的探讨在关节镜下经髌腱入路,利用空心拉力螺钉复位固定胫骨髁间嵴撕脱骨折(TEFx)的安全性和有效性。方法选取2014年1月-2015年12月23例TEFx的患者,均在关节镜下经髌腱入路,用空心拉力螺钉复位固定。术前Meyers-McKeever分型:Ⅱ型8例,Ⅲ型10例,Ⅳ型5例;男17例,女6例;年龄16～53岁,平均27.8岁。术前前抽屉试验、Lachman试验均阳性。比较术前术后的视觉模拟评分(VAS)、Lysholm、Tegner和国际膝关节文献委员会(IKDC)评分评价患侧膝关节功能。结果 23例患者均得到随访,随访时间30～40个月,平均36个月。术后即刻X线片示TEFx均复位良好,术后3个月骨折均愈合。无1例感染、关节僵硬、伸直受限、复位丢失及神经血管损伤等并发症。最终随访患侧膝关节活动度均恢复正常,前抽屉试验、Lachman试验均阴性。VAS评分术前(4.8±1.2)分,最终随访为(1.2±0.8)分,术前术后比较,差异有统计学意义(t=18.72,P=0.003);Lysholm评分术前为(50.8±6.2)分,最终随访为(90.8±5.4)分,术前术后比较,差异有统计学意义(t=-42.64,P=0.000);Tegner评分术前为(4.0±1.0)分,最终随访为(5.1±1.2)分,术前术后比较,差异有统计学意义(t=-16.82,P=0.005);IKDC主观评分术前为(52.5±7.4)分,最终随访为(91.5±5.7)分,术前术后比较,差异有统计学意义(t=-40.58,P=0.000)。结论膝关节镜下经髌腱入路空心拉力螺钉内固定治疗TEFx具有微创、操作简捷、固定可靠和恢复快的优点。     

A new total generalized variation induced spatial difference prior model for variational pansharpening

This letter proposed a new and effective total generalized variation (TGV) induced spatial difference prior model for variational pansharpening problem, which aimed to estimate a high-resolution (HR) multispectral (MS) image from its low-resolution (LR) version and the corresponding HR panchromatic (Pan) image of the same earth scene. In addition to using the local spectral consistency constraint for spectral information preserving, this letter particularly exploited the spatial difference prior between the HR-MS and Pan images, and hence proposed a new TGV-induced spatial difference prior term for spatial information preserving. Then, an efficient optimization algorithm was designed for solving the proposed model under the fast iterative shrinkage-thresholding algorithm (FISTA) framework. Finally, the experimental results validated that the proposed method performed higher spatial and spectral qualities than various methods in both the subjective and objective aspects.