Scale of interest versus scale of estimation: comparing alternative estimators for the incremental costs of a comorbidity

We investigate how the scale of estimation in risk-adjustment models for health-care costs affects the covariate effect, where the scale of interest for the covariate effect may be different from the scale of estimation. As an illustrative example, we use claims data to estimate the incremental costs associated with heart failure within one year subsequent to myocardial infarction. Here, the scale of interest for the effect of heart failure on costs is additive. However, traditional methods for modeling costs use predetermined scale of estimation - for example, ordinary least squares (OLS) regression assumes an additive scale while log-transformed OLS and generalized linear models with log-link assume a multiplicative scale of estimation. We compare these models with a new flexible model that lets the data determine the appropriate scale of estimation. We use a variety of goodness-of-fit measures along with a modified Copas test to assess robustness, lack of fit, and over-fitting properties of the alternative estimators. Biases up to 19% in the scale of interest are observed due to the misrepresentation of the scale of estimation. The new flexible model is found to appropriately represent the scale of estimation and less susceptible to over-fitting despite estimating additional parameters in the link and the variance functions.     

Nasal involvement in allergic asthma

Even since the late 19th century, a relationship has been suspected between upper airway disease and the subsequent development or aggravation of asthma symptoms. To date, it has been generally accepted that pathologic conditions of the upper airways, e.g. allergic rhinitis, chronic sinusitis and nasal polyposis, may influence the lower airways. However, the mechanisms underlying this relationship were, for a long time, poorly understood. Recently, evidence has been accumulating which indicates a systemic connection as one of the responsible mechanisms in nasobronchial crosstalk. In this review, the pathophysiologic and immunologic aspects of the interaction between upper and lower airways will be discussed.     

Non-collagenous protein screening in the human chondrodysplasias: Link proteins,cartilage oligomeric matrix protein (COMP), and fibromodulin

A gel-electrophoretic screening for link proteins, cartilage oligomeric matrix protein (COMP), and fibromodulin abnormalities was performed in fetuses, newborn infants, and children with various types of chondrodysplasia. Microdissected freeze-dried sections of upper tibial growth cartilage were extracted with 4M guanidinium chloride in the presence of proteolysis inhibitors. After dialysis against 8M urea, the extracts were submitted to stepwise ion-exchange chromatography to separate the large proteoglycans (aggrecans) from the other components. The latter were analyzed by gel electrophoresis, electrotransferred onto nitrocellulose membranes, and reacted with specific antibodies. Control samples from individuals with apparently normal growth were analyzed in the same runs. Two link protein bands with abnormal electrophoretic migration were found in a sporadic case of spondylometaphyseal dysplasia, Kozlowski type. Three link protein bands with the same migration as in the control samples were found in thanatophoric dysplasia, homozygous achondroplasia, achondrogenesis type II, hypochondrogenesis, Goldblatt syndrome, Desbuquois dysplasia, pseudo-achondroplasia, and diastrophic dysplasia. In several pathologic cases with normal electrophoretic pattern of the link proteins, small link protein fragments appeared after reduction. The gel electrophoretic pattern of COMP was studied in thanatophoric dysplasia, diastrophic dysplasia, homozygous achondroplasia, fibrochondrogenesis, hypochondrogenesis, Goldblatt syndrome, and Kniest dysplasia. In all these cases the pattern was the same as in the control samples. The main band of fibromodulin had a normal migration rate in fibrochondrogenesis, Desbuquois dysplasia, Kniest dysplasia, and pseudoachondroplasia. It was delayed in diastrophic dysplasia. © 1994 Wiley-Liss, Inc.     

TSG-6和连接蛋白在小鼠卵丘-卵母细胞复合体的共位性分析

目的：探讨小鼠卵丘-卵母细胞复合体(COC)中 TSG-6和连接蛋白(LP)与透明质酸(HA)的相关性。方法：应用激光扫描共聚焦显微镜和免疫荧光双重染色技术观察小鼠 COC 中 TSG-6和 LP 的表达和分布。结果： TSG-6和 LP 在 COC 中呈阳性表达。结论：TSG-6和 LP 的阳性表达可能和 HA 在 COC 成熟中起重要作用。     

60例牙周炎的临床体会

目的：观察米诺环素局部控释给药治疗牙周炎的临床疗效.方法： 应用米诺环素软膏缓释剂治疗40例成人牙周炎患者,并以20例患者口服米诺环素为对照组,进行对比研究,检测了治疗前后牙周炎的各项指标以及病变部位厌氧菌的变化.结果： 米诺环素软膏治疗成人牙周炎的疗效,优于对照组.米诺环素局部控释给药对口腔厌氧菌的杀灭效果较口服米诺环素强,用药后无任何毒副作用.结论： 米诺环素软膏临床效果显著,具有广阔应用前景.     

我单位综合布线系统的设计与实现

综合布线是一种模块化的、灵活性极高的建筑物内或建筑群之间的信息传输通道,是满足单位信息化需要,实现办公自动化、楼宇自动化等智能体系一个必不可少的基础环节。本文结合天津市疾病预防控制中心综合布线系统的实际应用,对综合布线系统设计的基本原则、系统组成、实现目标进行论述,总结出综合布线系统设计应注意的主要环节。     

腹股沟疝修补术102例体会

目的：通过对传统有张力疝修补术与疝环充填式无张力疝修补术的比较,评价无张力疝修补术在腹股沟疝中的应用价值。方法：对102例腹股沟疝修补术的临床资料进行回顾性分析。手术方法分为巴西尼（Bassini）法20例,弗格森（Fergusson）法5例,麦克维（McVay）法1例,疝环充填式无张力疝修补术76例。结果：传统式疝修补术创伤大,修补后局部组织张力高,伤口疼痛明显;无张力疝修补术局部组织无张力,切口疼痛轻,下床活动早,复发率低。76例疝环充填式无张力疝修补术,均一期愈合,无异物反应。结论：有张力疝修补术让位于无张力技术。无张力疝修补术应作为腹股沟疝的首选方式。     

关于全面提高研究生培养质量的探讨

全面提高研究生的培养质量,已经成为当前我国研究生教育改革和发展的主旋律。该文从研究生培养过程的各个环节入手,采取一系列有力措施,严抓研究生的培养质量,以适应新的教育形势的发展,培养创新型人才。     

Non-parametric estimation of the odds ratios for continuous exposures using generalized additive models with an unknown link function

The generalized additive, model (GAM) is a powerful and widely used tool that allows researchers to fit, non-parametrically, the effect of continuous predictors on a transformation of the mean response variable. Such a transformation is given by a so-called link function, and in GAMs this link function is assumed to be known. Nevertheless, if an incorrect choice is made for the link, the resulting GAM is misspecified and the results obtained may be misleading. In this paper, we propose a modified version of the local scoring algorithm that allows for the non-parametric estimation of the link function, by using local linear kernel smoothers. To better understand the effect that each covariate produces on the outcome, results are expressed in terms of the non-parametric odds ratio (OR) curves. Bootstrap techniques were used to correct the bias in the OR estimation and to construct point-wise confidence intervals. A simulation study was carried out to assess the behaviour of the resulting estimates. The proposed methodology was illustrated using data from the AIDS Register of Galicia (NW Spain), with a view to assessing the effect of the CD4 lymphocyte count on the probability of being AIDS-diagnosed via Tuberculosis (TB). This application shows how the link's flexibility makes it possible to obtain OR curve estimates that are less sensitive to the presence of outliers and unusual values that are often present in the extremes of the covariate distributions.