scholarly journals Tree Based Method for Aggregate Survival Data Modeling

2016 ◽  
Vol 12 (2) ◽  
Author(s):  
Asanao Shimokawa ◽  
Yoshitaka Narita ◽  
Soichiro Shibui ◽  
Etsuo Miyaoka
Keyword(s):  
Survival Data ◽  
Survival Function ◽  
Primary Brain Tumor ◽  
Aggregated Data ◽  
Tumor Patient ◽  
Kaplan Meier ◽  
Proposed Model ◽  
Tree Modeling ◽  
Variable Space ◽  
New Interpretation

AbstractIn many scenarios, a patient in medical research is treated as a statistical unit. However, in some scenarios, we are interested in treating aggregate data as a statistical unit. In such situations, each set of aggregated data is considered to be a concept in a symbolic representation, and each concept has a hyperrectangle or multiple points in the variable space. To construct a tree-structured model from these aggregate survival data, we propose a new approach, where a datum can be included in several terminal nodes in a tree. By constructing a model under this condition, we expect to obtain a more flexible model while retaining the interpretive ease of a hierarchical structure. In this approach, the survival function of concepts that are partially included in a node is constructed using the Kaplan-Meier method, where the number of events and risks at each time point is replaced by the expectation value of the number of individual descriptions of concepts. We present an application of this proposed model using primary brain tumor patient data. As a result, we obtained a new interpretation of the data in comparison to the classical survival tree modeling methods.

scholarly journals Hidden Imputations and the Kaplan-Meier Estimator

2020 ◽  
Vol 189 (11) ◽  
pp. 1408-1411 ◽  
Author(s):  
Stephen R Cole ◽  
Jessie K Edwards ◽  
Ashley I Naimi ◽  
Alvaro Muñoz
Keyword(s):  
Survival Data ◽  
Survival Function ◽  
Data Set ◽  
Kaplan Meier ◽  
Event Times

Abstract The Kaplan-Meier (KM) estimator of the survival function imputes event times for right-censored and left-truncated observations, but these imputations are hidden and therefore sometimes unrecognized by applied health scientists. Using a simple example data set and the redistribution algorithm, we illustrate how imputations are made by the KM estimator. We also discuss the assumptions necessary for valid analyses of survival data. Illustrating imputations hidden by the KM estimator helps to clarify these assumptions and therefore may reduce inappropriate inferences.

scholarly journals The Effect of Exclusive Breastfeeding on Child Survival Using Modified Kaplan Meier Model (MKMM)

2019 ◽  
pp. 1-10
Author(s):  
Moses Longji Dashal ◽  
Kazeem Eyitayo Lasisi ◽  
Kaneng Eileen Longji
Keyword(s):  
Exclusive Breastfeeding ◽  
Survival Data ◽  
Survival Probability ◽  
Survival Function ◽  
Child Survival ◽  
Food Supplement ◽  
Information Criteria ◽  
Kaplan Meier ◽  
Number Of Patients ◽  
Milk Substitute

Background: In Survival analysis, Kaplan-Meier estimator serves as a tool for measuring the frequency or the number of patients surviving medical treatment. Kaplan Meier estimates of survival data have become a better way of analyzing data in cohort study. Kaplan- Meier (K-M) is a non-parametric estimates of survival function that is commonly used to describe survivorship of a study population and to compare two study populations. Aims: This research study is aimed at reducing the morbidity and mortality rate of children less than 6 months. Methodology: 58,609 children less than six months were Exclusive Breastfed from the database. The analysis is done using both K-M and the modified K-M model to examine the effects of Exclusive Breastfeeding. The AIC and BIC was also used as the information criteria. Results: Our results revealed that the K-M model 0.998566822 as the estimated survival probability of children under the ages of six months. Also showing, Exclusively Breastfed children stand the chance of 99% survival. The modified K-M model also revealed 6.98276443909739 as the estimated survival probability, due to initiation of milk substitute and food supplement into the breastfeeding pattern. Showing about 70% chances of survival. Implying about 30% of the existence in one disease or the other or the risk of dying before the age of 5 years. From the information criteria, the AIC (2.3119452169420) and BIC (7.8478797677756) in the Modified K-M are both lower compared to Existing Kaplan Meier (4.0012457354876) and (9.5371847322969) respectively. Modified K-M stand as the best model in knowing the types/amount of food to be added to breastfeeding pattern. Conclusion: So far, the Modified Kaplan Meier Model has been verified and the findings agree that the life expectation will be improved by 99% if children are fed exclusively with breast milk while the life span is been reduced that can lead to death by 30% if the children have a mix feeding which agrees with why Exclusive Breastfeeding should be done.

Progression-free survival (PFS) and overall survival (OS) across ethnicities for patients with metastatic renal cell carcinoma (mRCC) receiving targeted therapies (TT) as first-line (1L) treatment.

2020 ◽  
Vol 38 (6_suppl) ◽  
pp. 645-645
Author(s):  
Nicholas Salgia ◽  
Nazli Dizman ◽  
Paulo Gustavo Bergerot ◽  
Cristiane Decat Bergerot ◽  
Joann Hsu ◽  
...  
Keyword(s):  
Ethnic Groups ◽  
Asian American ◽  
Survival Data ◽  
Survival Function ◽  
Progression Free Survival ◽  
Mtor Inhibitors ◽  
Caucasian American ◽  
Kaplan Meier ◽  
Significant Difference ◽  
The Relationship

645 Background: Recent efforts have sought to characterize differences in clinical and pathological characteristics across ethnicities in mRCC (Batai et al CGUC 2018), however, the relationship between ethnicity and treatment outcomes has yet to be explored. We sought to compare survival outcomes across ethnic groups for patients receiving 1L TT for treatment of mRCC. Methods: Patients receiving 1L systemic treatment for mRCC were retrospectively identified from a single institution database from 2009 to present. Patient ethnicity data were collected from electronic health records. Due to the demographics of the patient population, ethnicity was categorized as Non-Hispanic Caucasian American (CA), Hispanic American (HA), or Asian American (AsA). Patients prescribed tyrosine kinase and/or mTOR inhibitors as 1L therapy were included for analysis. PFS and OS were analyzed across ethnic groups and comparisons were performed using the Kaplan Meier Survival Function in SPSS. Results: Of 294 (77:217 F:M) patients with documented survival data, 183 (62%) were CA, 82 (28%) HA, and 29 (10%) AsA. The most frequently used TTs were sunitinib (63%), temsirolimus (10%), pazopanib (7%), sorafenib (5%), and cabozantinib (4%). Median PFS for CA was 5.6 months (95% Confidence Interval [CI]: 4.1-7.1) vs. 4.7 months (95% CI: 3.1-6.2) for HA vs. 4.7 months (95% CI: 2.1-7.3) for AsA. Median OS was 32.0 months (95% CI: 26.2-37.8) for CA vs. 31.7 months (95% CI: 21.1-42.4) for HA vs. 51.7 months (95% CI: 31.6-71.8) for AsA. No significant difference in PFS or OS was calculated across the three ethnic groups (p=0.652 and p=0.435, respectively). Conclusions: The lack of a statistically significant difference in both PFS and OS across ethnic groups is a promising assessment for the current landscape of health disparities in mRCC. As these data are distinct from recent findings identifying disparities in other malignancies (e.g., prostate cancer), multicenter collaborations should be encouraged to validate these findings.

scholarly journals AN APPLICATION OF THE POISSON-WEIBULL MODEL FOR CENSURED DATA

2021 ◽  
Vol 39 (4) ◽  
pp. 505-521
Author(s):  
Valdemiro Piedade VIGAS ◽  
Fábio PRATAVIERA ◽  
Giovana Oliveira SILVA
Keyword(s):  
Maximum Likelihood ◽  
Weibull Distribution ◽  
Survival Data ◽  
Real Data ◽  
Weibull Model ◽  
Maximum Likelihood Estimates ◽  
Data Set ◽  
Kaplan Meier ◽  
Proposed Model ◽  
The Mean

In this paper, we proposed the Poisson-Weibull distribution for the modeling of survival data. The motivation to study this model since, in addition to generalizing the Weibull distribution, which is widely used in several areas of knowledge among them the Survival and Reliability analysis, it presents great exibility in the forms of the hazard function. The Poisson-Weibull distribution was created in a composition of discrete and continuous distributions where there is no information about which factor was responsible for the component failure, only the minimum lifetime value among all risks is observed. The maximum likelihood approach was used to estimate the parameters of the model. Also was conducted a simulation study to examine the mean, the bias, and the root of the mean square error of the maximum likelihood estimates of the proposed model according to the censoring percentages and sample sizes. The model selection criteria were also applied, in addition to graphic techniques such as TTT-Plot and Kaplan-Meier. Application to the real data set was used to illustrate the usefulnessof the distribution.

Discreteness of Space and Its Consequences

2021 ◽  
pp. 132-141
Author(s):  
Аnatoly М. Shutyi ◽  
Keyword(s):  
Spatial Configuration ◽  
Relativistic Effects ◽  
Space Time ◽  
Maximum Speed ◽  
Speed Of Light ◽  
Quantum Uncertainty ◽  
Proposed Model ◽  
Spatial Configurations ◽  
New Interpretation ◽  
Component Particle

Based on the general principle of the unity of the nature of interacting entities and the principle of the relativity of motion, as well as following the requirement of an indissoluble and conditioning connection of space and time, the model of a discrete space-time consisting of identical interacting particles is proposed as the most acceptable one. We consider the consequences of the discreteness of space, such as: the occurrence of time quanta, the limiting speed of signal propa­gation, and the constancy of this speed, regardless of the motion of the reference frame. Regularly performed acts of particles of space-time (PST) interaction en­sure the connectivity of space, set the quantum of time and the maximum speed – the speed of light. In the process of PST communication, their mixing occurs, which ensures the relativity of inertial motion, and can also underlie quantum uncertainty. In this case, elementary particles are spatial configurations of an excited “lattice” of PST, and particles with mass must contain loop struc­tures in their configuration. A new interpretation of quantum mechanics is pro­posed, according to which the wave function determines the probability of de­struction of a spatial configuration (representing a quantum object) in its corresponding region, which leads to the contraction of the entire structure to a given, detectable component. Particle entanglement is explained by the appear­ance of additional links between the PST – the appearance of a local coordinate along which the distance between entangled objects does not increase. It is shown that the movement of a body should lead to an asymmetry of the tension of the bonds between the PST – to the asymmetry of its effective gravity, the es­tablishment of which is one of the possibilities for experimental verification of the proposed model. It is shown that the constancy of the speed of light in a vac­uum and the appearance of relativistic effects are based on ensuring the connec­tivity of space-time, i.e. striving to prevent its rupture.

scholarly journals SURVIVAL OF NONAGENARIAN PATIENTS WITH HIP FRACTURES: A COHORT STUDY

2017 ◽  
Vol 25 (4) ◽  
pp. 132-136 ◽  
Author(s):  
Alexa Ovidiu ◽  
Gheorghevici Teodor Stefan ◽  
Popescu Dragos ◽  
Veliceasa Bogdan ◽  
Alexa Ioana Dana
Keyword(s):  
Internal Fixation ◽  
Hip Fractures ◽  
Survival Data ◽  
Demographic Data ◽  
Level Of Evidence ◽  
Asa Score ◽  
Kaplan Meier ◽  
Trochanteric Region ◽  
One Year ◽  
Retrospective Comparative Study

ABSTRACT Objective: The objective of this study was to assess survival and factors that may influence survival in nonagenarians with hip fracture. Methods: We retrospectively analyzed 134 nonagenarian patients admitted for hip fractures over a period of 9 years, and reviewed medical records and survival data from the National Population Register. The analysis included demographic data, ASA score, surgical delay, type of treatment, and mortality. Results: Mean patient age was 92.53 years (range 90-103 years). Of the total, 35.8% of the fractures involved the femoral neck and 64.2% were in the trochanteric region. Overall mortality was 18.7% at 30 days, and 9% at one year. Mean survival for the entire sample was 683±78.1 days, with a median of 339 days; survival in men and women was 595±136.8 days and 734±94.6 days, respectively. We found that type of fracture (p=0.026) and ASA score (p=0.004) were the main factors influencing survival. Kaplan-Meier survival analysis indicated that patients with extracapsular fractures treated by internal fixation had a better survival rate (p=0.047). There was no significant differences between sexes (p = 0.102) or diagnosis (p = 0.537) Conclusion: Although nonagenarian patients have numerous comorbidities, surgical treatment using internal fixation seems superior to a conservative approach. Level of Evidence III, Retrospective Comparative Study.

scholarly journals Cox proportion hazard model for patients with hepatitis disease in Iraq

2009 ◽  
Vol 6 (3) ◽  
pp. 612-617
Author(s):  
Baghdad Science Journal
Keyword(s):  
Regression Model ◽  
Survival Time ◽  
Cox Regression ◽  
Survival Function ◽  
Hazard Model ◽  
Cox Regression Model ◽  
Hepatic Diseases ◽  
Kaplan Meier

Cox regression model have been used to estimate proportion hazard model for patients with hepatitis disease recorded in Gastrointestinal and Hepatic diseases Hospital in Iraq for (2002 -2005). Data consists of (age, gender, survival time terminal stat). A Kaplan-Meier method has been applied to estimate survival function and hazerd function.

Randomness in modified general relativity theory: The stochastic f(R) gravity model

2018 ◽  
Vol 96 (11) ◽  
pp. 1173-1177
Author(s):  
Tomer Shushi
Keyword(s):  
Gravity Field ◽  
Gravity Model ◽  
Gravity Models ◽  
Relativity Theory ◽  
Field Equations ◽  
Important Special Case ◽  
Proposed Model ◽  
Stochastic Space ◽  
Wavefunction Collapse ◽  
New Interpretation

We consider a stochastic modification of the f(R) gravity models, and provide its important properties, including the gravity field equations for the model. We show a prediction in which particles are localized by a system of random gravitational potentials. As an important special case, we investigate a gravity model in the presence of a small stochastic space–time perturbation and provide its gravity field equations. Using the proposed model we examine the stochastic quantum mechanics interpretation, and obtain a novel Schrödinger equation with gravitational potential that is based on diffusion in a gravitational field. Furthermore, we provide a new interpretation to the wavefunction collapse. It seems that the stochastic f(R) gravity model causes decoherence of the spatial superposition state of particles.

Impact of morphine use on mortality in STEMI patients treated with primary PCI - preliminary data from a new registry

2021 ◽  
Vol 28 (Supplement_1) ◽  
Author(s):  
D Szabo ◽  
A Szabo ◽  
IF Edes ◽  
D Becker ◽  
B Merkely ◽  
...  
Keyword(s):  
Propensity Score ◽  
Propensity Score Matching ◽  
Survival Data ◽  
Preliminary Data ◽  
Laboratory Data ◽  
Rank Test ◽  
Primary Pci ◽  
Kaplan Meier ◽  
P2y12 Antagonists ◽  
Current Guidelines

Abstract Funding Acknowledgements Type of funding sources: None. Background Opioids decrease the effect of P2Y12 receptor inhibitors in vitro and observational reports suggest that morphine use is associated with larger infarct size. Our research group presented previously, using a prospective single-center registry, that periprocedural morphine use may have no impact on long-term mortality in STEMI patients treated with primary PCI and clopidogrel. Purpose Our purpose is to check this interaction using a new registry of patients treated according to the current guidelines, including novel antiplatelet agents. Methods From May until November 2020, we collected 196 STEMI patients treated with primary PCI. 88 (44.9%) of them got morphine during the prehospital and periprocedural care. Baseline demographic, anamnestic, procedural, and laboratory data were collected. Survival data were analysed using Kaplan-Meier survival curves and the log-rank test. To adjust for confounding, a 1:1 propensity score-matching analysis was performed using 114 cases. Results An adequate balance on baseline covariates was achieved during propensity score-matching. Kaplan-Meier analysis showed no difference in 30-days mortality of the patients treated with or without morphine neither in the original nor in the propensity score-matched population (p = 0.094 and p = 0.309, respectively). Conclusion Our preliminary data suggest that morphine may have no impact on mortality in STEMI patients treated with primary PCI and medical therapy according to the current guidelines including novel P2Y12 antagonists. Abstract Figure. Kaplan-Meier curves

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