Survival Curve and Its Significance

1998 ◽  
pp. 169-193 ◽  
Author(s):  
Edward L. Alpen
Keyword(s):  
Survival Curve

Comparison of Quantification Methods of111In-Labelled Platelet Deposition in Peripheral Bypass Grafts

1987 ◽  
Vol 26 (02) ◽  
pp. 87-92 ◽  
Author(s):  
A. Verbruggen ◽  
C. De Bakker ◽  
A. Vandecruys ◽  
J. Joosten ◽  
A. Nevelsteen ◽  
...  
Keyword(s):  
Gamma Camera ◽  
Reliable Method ◽  
Survival Curve ◽  
Region Of Interest ◽  
Reference Region ◽  
Visual Interpretation ◽  
Bypass Grafts ◽  
Antithrombotic Drugs ◽  
Exponential Regression ◽  
Peripheral Bypass

The action of antithrombotic drugs can be evaluated by measuring the deposition of111In-labelled platelets on peripheral bypass grafts several days after injection. This evaluation can be performed qualitatively (visual interpretation on the daily images) or quantitatively. Four different methods which calculate the ratio of platelet uptake with a reference region are compared: two methods use a gamma camera and two a detector. A blood sample or the region under the sternal angle are used as reference. The daily ratio of the counts, recorded by a gamma camera in a region of interest covering the graft, and the blood radioactivity interpolated from a platelet survival curve appears to be the most reliable method. The information of all the ratios can be combined in a single thrombogenicity index which reflects the daily rise of a linear or exponential regression versus time.

scholarly journals Expression and clinical significance of miR-3615 in hepatocellular carcinoma

2021 ◽  
Vol 49 (1) ◽  
pp. 030006052098154
Author(s):  
Xin Yuan ◽  
Yize Zhang ◽  
Zujiang Yu
Keyword(s):  
Hepatocellular Carcinoma ◽  
Survival Curve ◽  
Clinicopathological Characteristics ◽  
The Cancer Genome Atlas ◽  
Prognostic Information ◽  
Ki 67 ◽  
Tissue Samples ◽  
Expression Levels ◽  
Kaplan Meier ◽  
Serum Alpha Fetoprotein

Objective To investigate the association between microRNA-3615 (miR-3615) expression and the prognosis and clinicopathological features in patients with hepatocellular carcinoma (HCC). Methods We obtained clinicopathological and genomic data and prognostic information on HCC patients from The Cancer Genome Atlas (TCGA) database. We then analyzed differences in miR-3615 expression levels between HCC and adjacent tissues using SPSS software, and examined the relationships between miR-3615 expression levels and clinicopathological characteristics. We also explored the influence of miR-3615 expression levels on the prognosis of HCC patients using Kaplan–Meier survival curve analysis. Results Based on data for 345 HCC and 50 adjacent normal tissue samples, expression levels of miR-3615 were significantly higher in HCC tissues compared with adjacent tissues. MiR-3615 expression levels in HCC patients were negatively correlated with overall survival time and positively correlated with high TNM stage, serum Ki-67 expression level, and serum alpha-fetoprotein level. There were no significant correlations between miR-3615 expression and age, sex, and pathological grade. Conclusion MiR-3615 may be a promising new biomarker and prognostic factor for HCC.

scholarly journals Adapting the Default Weighted Survival Analysis Modelling Approach to Model IFRS 9 LGD

Risks ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 103
Author(s):  
Morne Joubert ◽  
Tanja Verster ◽  
Helgard Raubenheimer ◽  
Willem D. Schutte
Keyword(s):  
Survival Analysis ◽  
Financial Reporting ◽  
Proportional Hazards ◽  
Proportional Hazards Model ◽  
Survival Curve ◽  
Cox Proportional Hazards ◽  
Cox Proportional Hazards Model ◽  
Reporting Standard ◽  
International Financial Reporting Standard ◽  
Ifrs 9

Survival analysis is one of the techniques that could be used to predict loss given default (LGD) for regulatory capital (Basel) purposes. When using survival analysis to model LGD, a proposed methodology is the default weighted survival analysis (DWSA) method. This paper is aimed at adapting the DWSA method (used to model Basel LGD) to estimate the LGD for International Financial Reporting Standard (IFRS) 9 impairment requirements. The DWSA methodology allows for over recoveries, default weighting and negative cashflows. For IFRS 9, this methodology should be adapted, as the estimated LGD is a function of in the expected credit losses (ECL). Our proposed IFRS 9 LGD methodology makes use of survival analysis to estimate the LGD. The Cox proportional hazards model allows for a baseline survival curve to be adjusted to produce survival curves for different segments of the portfolio. The forward-looking LGD values are adjusted for different macro-economic scenarios and the ECL is calculated for each scenario. These ECL values are probability weighted to produce a final ECL estimate. We illustrate our proposed IFRS 9 LGD methodology and ECL estimation on a dataset from a retail portfolio of a South African bank.

scholarly journals How well do neurosurgeons predict survival in patients with high-grade glioma?

2021 ◽  
Author(s):  
Lisa Millgård Sagberg ◽  
Asgeir S. Jakola ◽  
Ingerid Reinertsen ◽  
Ole Solheim
Keyword(s):  
Median Survival ◽  
Survival Curve ◽  
Binary Logistic Regression ◽  
High Grade Glioma ◽  
Accurate Estimation ◽  
Binary Logistic Regression Analysis ◽  
High Grade ◽  
Clinical Prediction ◽  
Individual Level ◽  
Actual Survival

AbstractDue to the lack of reliable prognostic tools, prognostication and surgical decisions largely rely on the neurosurgeons’ clinical prediction skills. The aim of this study was to assess the accuracy of neurosurgeons’ prediction of survival in patients with high-grade glioma and explore factors possibly associated with accurate predictions. In a prospective single-center study, 199 patients who underwent surgery for high-grade glioma were included. After surgery, the operating surgeon predicted the patient’s survival using an ordinal prediction scale. A survival curve was used to visualize actual survival in groups based on this scale, and the accuracy of clinical prediction was assessed by comparing predicted and actual survival. To investigate factors possibly associated with accurate estimation, a binary logistic regression analysis was performed. The surgeons were able to differentiate between patients with different lengths of survival, and median survival fell within the predicted range in all groups with predicted survival < 24 months. In the group with predicted survival > 24 months, median survival was shorter than predicted. The overall accuracy of surgeons’ survival estimates was 41%, and over- and underestimations were done in 34% and 26%, respectively. Consultants were 3.4 times more likely to accurately predict survival compared to residents (p = 0.006). Our findings demonstrate that although especially experienced neurosurgeons have rather good predictive abilities when estimating survival in patients with high-grade glioma on the group level, they often miss on the individual level. Future prognostic tools should aim to beat the presented clinical prediction skills.

scholarly journals The Association between Decreased Kidney Function and FIB-4 Index Value, as Indirect Liver Fibrosis Indicator, in Middle-Aged and Older Subjects

2021 ◽  
Vol 18 (13) ◽  
pp. 6980
Author(s):  
Kazuko Kotoku ◽  
Ryoma Michishita ◽  
Takuro Matsuda ◽  
Shotaro Kawakami ◽  
Natsumi Morito ◽  
...  
Keyword(s):  
Liver Fibrosis ◽  
Kidney Function ◽  
Survival Curve ◽  
Cross Sectional Study ◽  
Trend Test ◽  
Healthy Population ◽  
Middle Aged ◽  
Cross Sectional ◽  
Ckd Stage ◽  
Older Subjects

Liver fibrosis might be linked to the prevalence of chronic kidney disease (CKD). However, there is little information about the association between liver fibrosis and decreased kidney function in middle-aged and older subjects. We aimed to evaluate the influence of liver fibrosis on the incidence or prevalence of CKD stage 3–5 in a retrospective cross-sectional study (Study 1, n = 806) and a 6-year longitudinal study (Study 2, n = 380) of middle-aged and older subjects. We evaluated liver fibrosis using the Fibrosis-4 (FIB-4) index and kidney function using the estimated glomerular filtration rate (eGFR) of all subjects. All subjects were divided into four groups on the basis of their FIB-4 score quartiles (low to high). In the Jonckheere–Terpstra trend test of Study 1, the eGFR decreased significantly from the lowest group to the highest group (p < 0.001). The Kaplan–Meier survival curve in Study 2 showed that the cumulative prevalence of CKD stage 3–5 was higher in the third quartile than the other quartiles. Our results suggest that liver fibrosis could be a useful indicator for the prevalence of CKD, even within a relatively healthy population, although liver fibrosis was not an independent risk factor.

The impact of gender on outcomes in patients with chronic total coronary occlusions undergoing percutaneous coronary intervention: results from a Dutch nationwide registry including 7560 patients

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Van Veelen ◽  
J Elias ◽  
I.M Van Dongen ◽  
J.P.S Henriques ◽  
P Knaapen
Keyword(s):  
Cardiovascular Disease ◽  
Percutaneous Coronary Intervention ◽  
Survival Curve ◽  
Coronary Intervention ◽  
Chronic Total Occlusions ◽  
Nationwide Registry ◽  
Percutaneous Coronary ◽  
Baseline Characteristics ◽  
Gender Based ◽  
The Impact

Abstract Background Females comprise a minority of patients with chronic total occlusions (CTO). It is known that men have a greater benefit from CTO percutaneous coronary intervention (PCI) than women. We aimed to determine gender-based differences in baseline characteristics and outcomes after PCI in patients with CTO. Methods The Netherlands Heart Registration (NHR) is a nationwide registry that registers outcomes of cardiac interventions. For the purpose of this analysis, the data of all patients undergoing PCI from inception of the NHR to December 2018 were selected, that included PCI with at least one CTO in one of the treated coronary arteries. We compared baseline characteristics and the outcomes 1 year mortality, 30 day myocardial infarction (MI) and target vessel revascularization (TVR) &lt;1 year between men and women. Results A total of 7560 patients were identified that underwent PCI between January 1, 2015 and December 31, 2018 with at least 1 CTO in the treated vessel. A total of 5850 was male (77.4%) and 1710 was female (22.6%). Women were older (68.5±10.6 versus 64.7±10.6 years old, p&lt;0.001), and more frequently had diabetes (29.4% [n=529] versus 25.0% [n=1602], p&lt;0.001) and kidney disease (4.5% [n=529] versus 2.2% [n=142], p&lt;0.001). However, men had more extensive cardiovascular disease, i.e. multi-vessel disease (56.0% [n=3584] versus 50.4% [n=912], p&lt;0.001), previous MI (39.7% [n=2527] versus 31.0% [n=555], p&lt;0.001), previous PCI (48.2% [n=1967] versus 40.2% [n=455], p&lt;0.001) and previous coronary artery bypass grafting (16.8% [n=1085] versus 10.5% [n=191], p&lt;0.001) and more frequently presented with an out-of-hospital cardiac arrest, compared to women (2.1% [n=136] versus 1.1% [n=20], p=0.004). The 1-year mortality was higher in women (10.3% versus 7.5%, p&lt;0.001), as well as the 30-day MI (0.9% versus 0.4%, p=0.043), but men had higher risk for TVR&lt;1 year (11.7% versus 9.5%, p=0.044). Corrected for age and comorbidities, female gender was an independent predictor for mortality (Figure 1; odds ratio 1.83, 95% confidence interval 1.08–3.11, p=0.025). Conclusion In this nationwide registry comprising 7560 CTO patients undergoing PCI, significant gender-based differences were found. Males were found to have more extensive cardiovascular disease. However, females were at higher risk of mortality, possibly due to higher age and higher prevalence of concomitant comorbidities. Figure 1. Survival curve Funding Acknowledgement Type of funding source: None

scholarly journals Identification of ferroptosis genes in immune infiltration and prognosis in thyroid papillary carcinoma using network analysis

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ruoting Lin ◽  
Conor E. Fogarty ◽  
Bowei Ma ◽  
Hejie Li ◽  
Guoying Ni ◽  
...  
Keyword(s):  
Gene Expression ◽  
Thyroid Carcinoma ◽  
Risk Score ◽  
Immune Cells ◽  
Survival Curve ◽  
Enrichment Analysis ◽  
Papillary Thyroid ◽  
Hub Genes ◽  
Cox Analysis ◽  
Cluster 2

Abstract Background Papillary thyroid carcinoma (PTC) is the most common thyroid cancer. While many patients survive, a portion of PTC cases display high aggressiveness and even develop into refractory differentiated thyroid carcinoma. This may be alleviated by developing a novel model to predict the risk of recurrence. Ferroptosis is an iron-dependent form of regulated cell death (RCD) driven by lethal accumulation of lipid peroxides, is regulated by a set of genes and shows a variety of metabolic changes. To elucidate whether ferroptosis occurs in PTC, we analyse the gene expression profiles of the disease and established a new model for the correlation. Methods The thyroid carcinoma (THCA) datasets were downloaded from The Cancer Genome Atlas (TCGA), UCSC Xena and MisgDB, and included 502 tumour samples and 56 normal samples. A total of 60 ferroptosis related genes were summarised from MisgDB database. Gene set enrichment analysis (GSEA) and Gene set variation analysis (GSVA) were used to analyse pathways potentially involving PTC subtypes. Single sample GSEA (ssGSEA) algorithm was used to analyse the proportion of 28 types of immune cells in the tumour immune infiltration microenvironment in THCA and the hclust algorithm was used to conduct immune typing according to the proportion of immune cells. Spearman correlation analysis was performed on the ferroptosis gene expression and the correlation between immune infiltrating cells proportion. We established the WGCNA to identify genes modules that are highly correlated with the microenvironment of immune invasion. DEseq2 algorithm was further used for differential analysis of sequencing data to analyse the functions and pathways potentially involving hub genes. GO and KEGG enrichment analysis was performed using Clusterprofiler to explore the clinical efficacy of hub genes. Univariate Cox analysis was performed for hub genes combined with clinical prognostic data, and the results was included for lasso regression and constructed the risk regression model. ROC curve and survival curve were used for evaluating the model. Univariate Cox analysis and multivariate Cox analysis were performed in combination with the clinical data of THCA and the risk score value, the clinical efficacy of the model was further evaluated. Results We identify two subtypes in PTC based on the expression of ferroptosis related genes, with the proportion of cluster 1 significantly higher than cluster 2 in ferroptosis signature genes that are positively associated. The mutations of Braf and Nras are detected as the major mutations of cluster 1 and 2, respectively. Subsequent analyses of TME immune cells infiltration indicated cluster 1 is remarkably richer than cluster 2. The risk score of THCA is in good performance evaluated by ROC curve and survival curve, in conjunction with univariate Cox analysis and multivariate Cox analysis results based on the clinical data shows that the risk score of the proposed model could be used as an independent prognostic indicator to predict the prognosis of patients with papillary thyroid cancer. Conclusions Our study finds seven crucial genes, including Ac008063.2, Apoe, Bcl3, Acap3, Alox5ap, Atxn2l and B2m, and regulation of apoptosis by parathyroid hormone-related proteins significantly associated with ferroptosis and immune cells in PTC, and we construct the risk score model which can be used as an independent prognostic index to predict the prognosis of patients with PTC.

Use of a Modified Gompertz Equation to Predict the Effects of Temperature, pH, and NaCl on the Inactivation of Listeria monocytogenes Scott A Heated in Infant Formula

1996 ◽  
Vol 59 (1) ◽  
pp. 16-23 ◽  
Author(s):  
R. H. LINTON ◽  
W. H. CARTER ◽  
M. D. PIERSON ◽  
C. R. HACKNEY ◽  
J. D. EIFERT
Keyword(s):  
Listeria Monocytogenes ◽  
Infant Formula ◽  
Nonlinear Regression ◽  
Survival Curve ◽  
Interactive Effects ◽  
Parameter Estimates ◽  
Survival Curves ◽  
Gompertz Equation ◽  
Nacl Concentration ◽  
Effects Of Temperature

The heat resistance of Listeria monocytogenes was determined in infant formula for all possible combinations of temperature (50, 55, and 60°C), pH level (5, 6, and 7), and NaCl concentration (0, 2, and 4%). Survival curves were fit using nonlinear regression with a Gompertz equation. The Gompertz equation was flexible enough to fit the three most commonly observed survival curves: linear curves, those with an initial lag region followed by a linear region, and sigmoidal shaped. Parameter estimates obtained by the method of nonlinear least squares were used to describe the effect(s) of different heating treatments on the lag region, death rate, and tailing region of survival curves. These estimates were further used to predict single and interactive effects of temperature, pH, and percentage of NaCl on the log of the surviving fraction (LSF) of bacteria. Interactions among these variables significantly (P ≤ .05) affected the LSF. Generally, increased pH or NaCl concentration lead to an increased LSF, whereas increased time or temperature lead to a decreased LSF. All multiple-factor interactions significantly (P ≤ .05) affected the LSF. The correlation of observed LSF versus predicted LSF (R2 = .92) indicated that the estimated Gompertz equation was in close agreement with the observation. This study demonstrated that the Gompertz equation and nonlinear regression can be used as an effective means to predict survival curve shape and response to heat of L. monocytogenes under many different environmental conditions.

A unified degree day model describes survivorship of Copitarsia corruda Pogue & Simmons (Lepidoptera: Noctuidae) at different constant temperatures

2008 ◽  
Vol 99 (1) ◽  
pp. 65-72 ◽  
Author(s):  
N.N. Gómez ◽  
R.C. Venette ◽  
J.R. Gould ◽  
D.F. Winograd
Keyword(s):  
Survival Curve ◽  
The United States ◽  
Physiological Age ◽  
Alien Invasive Species ◽  
Temperature Threshold ◽  
Base Temperature ◽  
Survival Curves ◽  
Degree Day ◽  
Effects Of Temperature ◽  
Lepidoptera Noctuidae

AbstractPredictions of survivorship are critical to quantify the probability of establishment by an alien invasive species, but survival curves rarely distinguish between the effects of temperature on development versus senescence. We report chronological and physiological age-based survival curves for a potentially invasive noctuid, recently described as Copitarsia corruda Pogue & Simmons, collected from Peru and reared on asparagus at six constant temperatures between 9.7 and 34.5°C. Copitarsia spp. are not known to occur in the United States but are routinely intercepted at ports of entry. Chronological age survival curves differ significantly among temperatures. Survivorship at early age after hatch is greatest at lower temperatures and declines as temperature increases. Mean longevity was 220 (±13 SEM) days at 9.7°C. Physiological age survival curves constructed with developmental base temperature (7.2°C) did not correspond to those constructed with a senescence base temperature (5.9°C). A single degree day survival curve with an appropriate temperature threshold based on senescence adequately describes survivorship under non-stress temperature conditions (5.9–24.9°C).

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