Review of An Introduction to Survival Analysis Using Stata

The new book by Cleves et al. (2002) is reviewed. Copyright 2002 by Stata Corporation.

Review of An Introduction to Survival Analysis Using Stata

The new book by Cleves et al. (2002) is reviewed. Copyright 2002 by Stata Corporation.

Curso intensivo de regresion logistica

Núm al catàleg de Patrimoni: 3887 (institut Mental i Església)Bernader, J. O

Survival Rates in Trauma Patients Following Health Care Reform in Massachusetts

IMPORTANCE: Massachusetts introduced health care reform (HCR) in 2006, expecting to expand health insurance coverage and improve outcomes. Because traumatic injury is a common acute condition with important health, disability, and economic consequences, examination of the effect of HCR on patients hospitalized following injury may help inform the national HCR debate. OBJECTIVE: To examine the effect of Massachusetts HCR on survival rates of injured patients. DESIGN, SETTING, AND PARTICIPANTS: Retrospective cohort study of 1,520,599 patients hospitalized following traumatic injury in Massachusetts or New York during the 10 years (2002-2011) surrounding Massachusetts HCR using data from the State Inpatient Databases. We assessed the effect of HCR on mortality rates using a difference-in-differences approach to control for temporal trends in mortality. INTERVENTION: Health care reform in Massachusetts in 2006. MAIN OUTCOME AND MEASURE: Survival until hospital discharge. RESULTS: During the 10-year study period, the rates of uninsured trauma patients in Massachusetts decreased steadily from 14.9% in 2002 to 5.0.% in 2011. In New York, the rates of uninsured trauma patients fell from 14.9% in 2002 to 10.5% in 2011. The risk-adjusted difference-in-difference assessment revealed a transient increase of 604 excess deaths (95% CI, 419-790) in Massachusetts in the 3 years following implementation of HCR. CONCLUSIONS AND RELEVANCE: Health care reform did not affect health insurance coverage for patients hospitalized following injury but was associated with a transient increase in adjusted mortality rates. Reducing mortality rates for acutely injured patients may require more comprehensive interventions than simply promoting health insurance coverage through legislation

Purposeful selection of variables in logistic regression

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

New firm survival in developing countries: evidence from Kosovo

This paper examines both newborn firm survival and firm turnover in Kosovo using the population of new firms and registry information on active firms from 2008 to 2012. Survival analysis is employed to analyze the impact of firm- and industry-level characteristics on survival. We find that the hazard rate has an inverted U-shape relationship with both firm age and firm size. The risk of failure increases over the first two years and later decreases. In addition, firms with one employee and more than 10 employees enjoy better survival prospects than medium-sized companies. Interestingly, very large firms do not face fewer risks than very small companies. When compared to other developing countries, entry rates are lower but survival rates are higher. These features seem to be a distinctive characteristic of Kosovo

Impact of a physician intervention program to increase breast cancer screening

In order to improve compliance with the National Cancer Institute\u27s breast cancer screening guidelines, we developed a multifaceted intervention designed to alter physician screening practice. A pre-post test, two-community design was used. Primary care physicians in one community served as the control. Data were collected by two mailed surveys (1987 and 1990). Response rates were 61% and 64%, respectively. The physician intervention program consisted of a hospital-based continuing medical education program and an outreach component which focused on implementing a reminder system. Outcome measures were self-reported attitudinal, knowledge, and screening practices changes. In spite of an impressive change in comparison community physicians\u27 practice, the difference in change over time in the intervention community physicians\u27 ordering of annual mammography compared to the change in the comparison community physicians\u27 ordering was significant (P = 0.04). The adjusted odds ratio is nearly 8. We conclude that our in-service continuing medical education program was successful in improving breast cancer screening practices among primary care physicians

HIV Services Utilization in Los Angeles County, California

Recipients of HIV/AIDS prevention services in Los Angeles County California were surveyed in 2004 by 220 HIV prevention service provider staff from 51 agencies funded by the Office of AIDS Programs and Policy. This resulted in 2,102 usable surveys for cluster analysis purposes. This Countywide Risk Assessment Survey assessed demographics, sexual history, substance use, perceptions regarding HIV/AIDS, and use of 18 different services at both the agency administering the survey and at other agencies. The 36 types of service use data were subjected to a cluster analysis that found five clusters. These service pattern clusters differed from each other on proportion HIV positive, HIV testing history, history of abuse, education, type of residence, type of funding, intervention type, and ethnicity. The analysis also suggests that domestic violence services availability and utilization should be examined more thoroughly in the future for HIV infected/affected populations

Investigating the impact of chronic atrazine exposure on sexual development in zebrafish

Atrazine (ATZ) is a selective triazine herbicide used primarily for pre-emergent weed control in corn, sorghum and sugar cane production. It is one of the most widely used herbicides in North America. Some research published over the last decade suggests that chronic exposure to environmentally relevant ATZ concentrations can adversely impact gonadal development and/or sexual differentiation in amphibians and fish, while other studies report no effect, or moderate effects. As a result, contrasting conclusions have been published regarding the potential effects of the herbicide ATZ on aquatic species. Two near-identical four-month studies in 2009 (Study I) and 2010 (Study II), were performed investigating the potential for chronic ATZ exposure to affect zebrafish (Danio rerio) sexual development and differentiation. Zebrafish, were chronically exposed to 0, 0.1, 1, 10 μM ATZ or 1 nM 17ß-estradiol (E2). Fish were histologically examined to assign gender and to evaluate potential impacts of E2 or ATZ on gonadal development. Exposure to E2 consistently resulted in a significantly higher proportion of female fish to normal male fish when compared to unexposed fish (both studies). In both studies, ATZ exposure did not significantly influence the percentage of female or male fish when compared to unexposed fish. A greater percentage of abnormally developed male fish and fish lacking differentiated gonadal tissue was observed in Study II E2 exposures but not in ATZ exposures. Together, these studies indicate that long-term exposure to ATZ at or above environmentally relevant concentrations does not significantly impact zebrafish gonadal development or sexual differentiation.Keywords: chronic exposure, zebrafish, atrazine, sex differentiation, sexual developmentKeywords: chronic exposure, zebrafish, atrazine, sex differentiation, sexual developmen

Association of the TLR4 Asp299Gly polymorphism with lung function in relation to body mass index

<p>Abstract</p> <p>Background</p> <p>Previous studies have shown conflicting results for the association between TLR4 polymorphism (Asp299Gly) and lung function. We investigated the influence of TLR4 Asp299Gly, a polymorphism, on lung function in a community population.</p> <p>Methods</p> <p>In 2003, a cross-sectional survey was conducted to assess the respiratory health of residents living in and around the town of Humboldt, Saskatchewan, Canada. There were 2090 adults age 18-79 years who completed a questionnaire that included a medical and smoking history, as well as socio-economic and lifestyle variables. Genetic information and lung function test measurements were available on 1725 subjects (754 males and 971 females) of the 2090 respondents. These subjects were selected for further analysis to investigate the association between TLR4 Asp299Gly genotype and forced expiratory volume in the first second in liters (FEV₁), forced vital capacity in liters (FVC), FEV₁/FVC ratio, and forced expiratory flow rate in liters/second (FEF_25-75). Multivariable linear regression analysis was used to investigate associations.</p> <p>Results</p> <p><b>A</b>djusted mean values of FEV₁and FVC were significantly different between TLR4 wild type and TLR4 variant groups [Mean ± S.E.: (TLR4 wild type - FEV₁: 3.18 ± 0.02, FVC: 3.95 ± 0.03; TLR4 variant - FEV₁: 3.31 ± 0.06, FVC: 4.14 ± 0.07)]. Based on multivariable regression analysis, we observed that body mass index (BMI) was associated with decreased FEV₁/FVC ratio and FEF_25-75in TLR4 variant group but not in wild type group.</p> <p>Conclusion</p> <p>BMI may modify the associations of TLR4 Asp299Gly polymorphism with FEV₁/FVC ratio and FEF_25-75.</p