Use of the Living Kidney Donor Profile Index in the Canadian Kidney Transplant Recipient Population: A Validation Study

Background: The Living Kidney Donor Profile Index (LKDPI) was derived in a cohort of kidney transplant recipients (KTR) from the United States to predict the risk of total graft failure. There are important differences in patient demographics, listing practices, access to transplantation, delivery of care, and posttransplant mortality in Canada as compared with the United States, and the generalizability of the LKDPI in the Canadian context is unknown. Objective: The purpose of this study was to externally validate the LKDPI in a large contemporary cohort of Canadian KTR. Design: Retrospective cohort validation study. Setting: Toronto General Hospital, University Health Network, Toronto, Ontario, Canada Patients: A total of 645 adult (≥18 years old) living donor KTR between January 1, 2006 and December 31, 2016 with follow-up until December 31, 2017 were included in the study. Measurements: The predictive performance of the LKDPI was evaluated. The outcome of interest was total graft failure, defined as the need for chronic dialysis, retransplantation, or death with graft function. Methods: The Cox proportional hazards model was used to examine the relation between the LKDPI and total graft failure. The Cox proportional hazards model was also used for external validation and performance assessment of the model. Discrimination and calibration were used to assess model performance. Discrimination was assessed using Harrell’s C statistic and calibration was assessed graphically, comparing observed versus predicted probabilities of total graft failure. Results: A total of 645 living donor KTR were included in the study. The median LKDPI score was 13 (interquartile range [IQR] = 1.1, 29.9). Higher LKDPI scores were associated with an increased risk of total graft failure (hazard ratio = 1.01; 95% confidence interval [CI] = 1.0-1.02; P = .02). Discrimination was poor (C statistic = 0.55; 95% CI = 0.48-0.61). Calibration was as good at 1-year posttransplant but suboptimal at 3- and 5-years posttransplant. Limitations: Limitations include a relatively small sample size, predicted probabilities for assessment of calibration only available for scores of 0 to 100, and some missing data handled by imputation. Conclusions: In this external validation study, the predictive ability of the LKDPI was modest in a cohort of Canadian KTR. Validation of prediction models is an important step to assess performance in external populations. Potential recalibration of the LKDPI may be useful prior to clinical use in external cohorts.

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Incidence and Survival Changes in Patients with Esophageal Adenocarcinoma during 1984–2013

BioMed Research International ◽

10.1155/2019/7431850 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Zhang Haiyu ◽

Pei Xiaofeng ◽

Mo Xiangqiong ◽

Qiu Junlan ◽

Zheng Xiaobin ◽

...

Keyword(s):

United States ◽

Risk Factors ◽

Esophageal Adenocarcinoma ◽

Proportional Hazards ◽

Proportional Hazards Model ◽

The United States ◽

Cox Proportional Hazards ◽

Cox Proportional Hazards Model ◽

Hazards Model ◽

Potential Risk Factors

Purpose. The morbidity of esophageal adenocarcinoma (EAC) has significantly increased in Western countries. We aimed to identify trends in incidence and survival in patients with EAC in the recent 30 years and then analyzed potential risk factors, including race, sex, age, and socioeconomic status (SES). Methods. All data were collected from the Surveillance, Epidemiology, and End Results or SEER database. Kaplan–Meier analysis and the Cox proportional hazards model were conducted to compare the differences in survival between variables, including sex, race, age, and SES, as well as to evaluate the association of these factors with prognosis. Results. A total of 16,474 patients with EAC were identified from 1984 to 2013 in the United States. Overall incidence increased every 10 years from 1.8 to 3.1 to 3.9 per 100. Overall survival gradually improved (p<0.0001), which was evident in male patients ((hazard ratio (HR) = 1.111; 95% confidence interval (CI) (1.07, 1.15)); however, the 5-year survival rate remained low (20.1%). The Cox proportional hazards model identified old age, black ethnicity, and medium/high poverty as risk factors for EAC (HR = 1.018; 95% CI (1.017, 1.019; HR = 1.240, 95% CI (1.151,1.336), HR = 1.000, 95% CI (1.000, 1.000); respectively). Conclusions. The incidence of EAC in the United States increased over time. Survival advantage was observed in white patients and patients in the low-poverty group. Sex was an independent prognostic factor for EAC, but this finding has to be confirmed by further research.

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Survival Analysis of COVID-19 on Democracy with Cox Proportional Hazards Model

10.21203/rs.3.rs-33141/v1 ◽

2020 ◽

Author(s):

Yue Zhao ◽

Deepika Dilip

Keyword(s):

United States ◽

Survival Analysis ◽

South Korea ◽

Proportional Hazards ◽

Proportional Hazards Model ◽

The United States ◽

Cox Proportional Hazards ◽

Cox Proportional Hazards Model ◽

Effective Measure ◽

Hazards Model

Abstract Background: The outbreak of Coronavirus disease 2019 (COVID-19) has struck us in many ways and we observed that China and South Korea found an effective measure to contain the virus. Conversely, the United States and the European countries are struggling to fight the virus. China is not considered a democracy and South Korea is less democratic than the United States. Therefore, we want to explore the association between the deaths of COVID-19 and democracy. Methods: We collected COVID-19 deaths data for each country from the Johns Hopkins University website and democracy indices of 2018 from the Economist Intelligence Unit website in May 2020. Then we conducted a survival analysis, regarding each country as a subject, with the Cox Proportional Hazards Model, adjusting for other selected variables. Result: The result showed that the association between democracy and deaths of COVID-19 was significant (P=0.04), adjusting for other covariates. Conclusion: In conclusion, less democratic governments performed better in containing the virus and controlling the number of deaths.

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Comparison of Valvulopathy Risk with Lorcaserin and Phenterminetopiramate for Weight Loss

Current Drug Therapy ◽

10.2174/1574885513666180503141557 ◽

2019 ◽

Vol 14 (1) ◽

pp. 74-78

Author(s):

Michael Guo ◽

Mahyar Etminan ◽

Bruce Carleton

Keyword(s):

Weight Loss ◽

Proportional Hazards ◽

Proportional Hazards Model ◽

Adverse Outcome ◽

The United States ◽

Cox Proportional Hazards ◽

Cox Proportional Hazards Model ◽

Hazards Model ◽

Hazard Ratios ◽

One Year

Background: Lorcaserin and phentermine-topiramate are two drugs marketed for obesity that have shown moderate efficacy after one year of use. However, concerns over risks of serious cardiovascular harms including valvulopathy have been brought up for both drugs, prompting an epidemiologic investigation to quantify this adverse outcome using real-world clinical data. Objective: To compare rates of valvulopathy between the weight-loss drugs lorcaserin and phentermine-topiramate. Methods: A retrospective cohort study using the PharMetrics database from the United States was conducted. From approximately 9 million subjects captured in the database from 2006 to 2016, we identified all patients who had received at least one prescription for lorcaserin or phentermine-topiramate. Users of either drug were followed to the first mutually exclusive diagnosis of non-congenital valvulopathy defined as having received an international classification for diseases, ninth revision clinical modification [ICD-9- CM] code for valvulopathy, or to the end of the study period. A Cox Proportional Hazards model was then constructed to compute adjusted hazard ratios (HRs) to compare the rates of valvulopathy between users of the two drugs. Results: We identified 1,981 lorcaserin users and 1,806 phentermine-topiramate users. Rates of valvulopathy for lorcaserin and phentermine-topiramate cohorts were 26 and 24 per 1000-person-years, respectively. The crude and adjusted hazard ratios (HRs) comparing the two cohorts with respect to valvulopathy were 1.28 (95% CI: 0.73,2.26) and 1.16 (95% CI: 0.65-2.05), respectively. Conclusion: Our analysis suggests comparable rates of valvulopathy between lorcaserin and phentermine-topiramate users. Clinicians are advised to consider the risk of valvular disease when medically managing obesity.

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A novel 14-gene signature for overall survival in lung adenocarcinoma based on the Bayesian hierarchical Cox proportional hazards model

Scientific Reports ◽

10.1038/s41598-021-03645-6 ◽

2022 ◽

Vol 12 (1) ◽

Author(s):

Na Sun ◽

Jiadong Chu ◽

Wei Hu ◽

Xuanli Chen ◽

Nengjun Yi ◽

...

Keyword(s):

Lung Adenocarcinoma ◽

Prognostic Model ◽

Proportional Hazards ◽

Proportional Hazards Model ◽

External Validation ◽

Gene Signature ◽

Cox Proportional Hazards ◽

Cox Proportional Hazards Model ◽

Bayesian Hierarchical ◽

Hazards Model

AbstractThere have been few investigations of cancer prognosis models based on Bayesian hierarchical models. In this study, we used a novel Bayesian method to screen mRNAs and estimate the effects of mRNAs on the prognosis of patients with lung adenocarcinoma. Based on the identified mRNAs, we can build a prognostic model combining mRNAs and clinical features, allowing us to explore new molecules with the potential to predict the prognosis of lung adenocarcinoma. The mRNA data (n = 594) and clinical data (n = 470) for lung adenocarcinoma were obtained from the TCGA database. Gene set enrichment analysis (GSEA), univariate Cox proportional hazards regression, and the Bayesian hierarchical Cox proportional hazards model were used to explore the mRNAs related to the prognosis of lung adenocarcinoma. Multivariate Cox proportional hazard regression was used to identify independent markers. The prediction performance of the prognostic model was evaluated not only by the internal cross-validation but also by the external validation based on the GEO dataset (n = 437). With the Bayesian hierarchical Cox proportional hazards model, a 14-gene signature that included CPS1, CTPS2, DARS2, IGFBP3, MCM5, MCM7, NME4, NT5E, PLK1, POLR3G, PTTG1, SERPINB5, TXNRD1, and TYMS was established to predict overall survival in lung adenocarcinoma. Multivariate analysis demonstrated that the 14-gene signature (HR 3.960, 95% CI 2.710–5.786), T classification (T1, reference; T3, HR 1.925, 95% CI 1.104–3.355) and N classification (N0, reference; N1, HR 2.212, 95% CI 1.520–3.220; N2, HR 2.260, 95% CI 1.499–3.409) were independent predictors. The C-index of the model was 0.733 and 0.735, respectively, after performing cross-validation and external validation, a nomogram was provided for better prediction in clinical application. Bayesian hierarchical Cox proportional hazards models can be used to integrate high-dimensional omics information into a prediction model for lung adenocarcinoma to improve the prognostic prediction and discover potential targets. This approach may be a powerful predictive tool for clinicians treating malignant tumours.

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Risk factors associated with major adverse cardiac and cerebrovascular events following percutaneous coronary intervention: a 10-year follow-up comparing random survival forest and Cox proportional-hazards model

BMC Cardiovascular Disorders ◽

10.1186/s12872-020-01834-1 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Maryam Farhadian ◽

Sahar Dehdar Karsidani ◽

Azadeh Mozayanimonfared ◽

Hossein Mahjub

Keyword(s):

Proportional Hazards ◽

Proportional Hazards Model ◽

Coronary Intervention ◽

Cox Proportional Hazards ◽

Cox Proportional Hazards Model ◽

Hazards Model ◽

Cerebrovascular Events ◽

Long Term Follow Up ◽

Stent Length

Abstract Background Due to the limited number of studies with long term follow-up of patients undergoing Percutaneous Coronary Intervention (PCI), we investigated the occurrence of Major Adverse Cardiac and Cerebrovascular Events (MACCE) during 10 years of follow-up after coronary angioplasty using Random Survival Forest (RSF) and Cox proportional hazards models. Methods The current retrospective cohort study was performed on 220 patients (69 women and 151 men) undergoing coronary angioplasty from March 2009 to March 2012 in Farchshian Medical Center in Hamadan city, Iran. Survival time (month) as the response variable was considered from the date of angioplasty to the main endpoint or the end of the follow-up period (September 2019). To identify the factors influencing the occurrence of MACCE, the performance of Cox and RSF models were investigated in terms of C index, Integrated Brier Score (IBS) and prediction error criteria. Results Ninety-six patients (43.7%) experienced MACCE by the end of the follow-up period, and the median survival time was estimated to be 98 months. Survival decreased from 99% during the first year to 39% at 10 years' follow-up. By applying the Cox model, the predictors were identified as follows: age (HR = 1.03, 95% CI 1.01–1.05), diabetes (HR = 2.17, 95% CI 1.29–3.66), smoking (HR = 2.41, 95% CI 1.46–3.98), and stent length (HR = 1.74, 95% CI 1.11–2.75). The predictive performance was slightly better by the RSF model (IBS of 0.124 vs. 0.135, C index of 0.648 vs. 0.626 and out-of-bag error rate of 0.352 vs. 0.374 for RSF). In addition to age, diabetes, smoking, and stent length, RSF also included coronary artery disease (acute or chronic) and hyperlipidemia as the most important variables. Conclusion Machine-learning prediction models such as RSF showed better performance than the Cox proportional hazards model for the prediction of MACCE during long-term follow-up after PCI.

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Elevated plasma growth and differentiation factor 15 predicts incident anemia in older adults aged 60 years and older

The Journals of Gerontology Series A ◽

10.1093/gerona/glaa324 ◽

2020 ◽

Author(s):

Yuko Yamaguchi ◽

Marta Zampino ◽

Toshiko Tanaka ◽

Stefania Bandinelli ◽

Yusuke Osawa ◽

...

Keyword(s):

Older Adults ◽

Proportional Hazards ◽

Proportional Hazards Model ◽

Cox Proportional Hazards ◽

Cox Proportional Hazards Model ◽

Differentiation Factor ◽

Hazards Model ◽

Increased Risk ◽

The Relationship

Abstract Background Anemia is common in older adults and associated with greater morbidity and mortality. The causes of anemia in older adults have not been completely characterized. Although elevated circulating growth and differentiation factor 15 (GDF-15) has been associated with anemia in older adults, it is not known whether elevated GDF-15 predicts the development of anemia. Methods We examined the relationship between plasma GDF-15 concentrations at baseline in 708 non-anemic adults, aged 60 years and older, with incident anemia during 15 years of follow-up among participants in the Invecchiare in Chianti (InCHIANTI) Study. Results During follow-up, 179 (25.3%) participants developed anemia. The proportion of participants who developed anemia from the lowest to highest quartile of plasma GDF-15 was 12.9%, 20.1%, 21.2%, and 45.8%, respectively. Adults in the highest quartile of plasma GDF-15 had an increased risk of developing anemia (Hazards Ratio 1.15, 95% Confidence Interval 1.09, 1.21, P<.0001) compared to those in the lower three quartiles in a multivariable Cox proportional hazards model adjusting for age, sex, serum iron, soluble transferrin receptor, ferritin, vitamin B12, congestive heart failure, diabetes mellitus, and cancer. Conclusions Circulating GDF-15 is an independent predictor for the development of anemia in older adults.

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Dementia Adjudication Triggers Associated With Increased Mortality for Older Australians: Evidence From ASPREE

Innovation in Aging ◽

10.1093/geroni/igaa057.523 ◽

2020 ◽

Vol 4 (Supplement_1) ◽

pp. 161-161

Author(s):

Jane Banaszak-Holl ◽

Xiaoping Lin ◽

Jing Xie ◽

Stephanie Ward ◽

Henry Brodaty ◽

...

Keyword(s):

Proportional Hazards ◽

Proportional Hazards Model ◽

The Elderly ◽

Cox Proportional Hazards ◽

Service Planning ◽

Cox Proportional Hazards Model ◽

Cognitive Test ◽

Risk Of Death ◽

Hazards Model ◽

Using Data

Abstract Research Aims: This study seeks to understand whether those with dementia experience higher risk of death, using data from the ASPREE (ASPirin in Reducing Events in the Elderly) clinical trial study. Methods: ASPREE was a primary intervention trial of low-dose aspirin among healthy older people. The Australian cohort included 16,703 dementia-free participants aged 70 years and over at enrolment. Participants were triggered for dementia adjudication if cognitive test results were poorer than expected, self-reporting dementia diagnosis or memory problems, or dementia medications were detected. Incidental dementia was adjudicated by an international adjudication committee using the Diagnostic and Statistical Manual for Mental Disorders (DSM-IV) criteria and results of a neuropsychological battery and functional measures with medical record substantiation. Statistical analyses used a cox proportional hazards model. Results: As previously reported, 1052 participants (5.5%) died during a median of 4.7 years of follow-up and 964 participants had a dementia trigger, of whom, 575 (60%) were adjucated as having dementia. Preliminary analyses has shown that the mortality rate was higher among participants with a dementia trigger, regardless of dementia adjudication outcome, than those without (15% vs 5%, Χ2 = 205, p <.001). Conclusion: This study will provide important analyses of differences in the hazard ratio for mortality and causes of death among people with and without cognitive impairment and has important implications on service planning.

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Evaluation of Changes on World Stock Exchanges in Connection with the SARS-CoV-2 Pandemic. Survival Analysis Methods

Risks ◽

10.3390/risks9070121 ◽

2021 ◽

Vol 9 (7) ◽

pp. 121

Author(s):

Beata Bieszk-Stolorz ◽

Krzysztof Dmytrów

Keyword(s):

Survival Analysis ◽

Proportional Hazards ◽

Proportional Hazards Model ◽

Stock Exchange ◽

Cox Proportional Hazards ◽

Cox Proportional Hazards Model ◽

Stock Exchanges ◽

Analysis Methods ◽

Hazards Model ◽

Kaplan Meier

The aim of our research was to compare the intensity of decline and then increase in the value of basic stock indices during the SARS-CoV-2 coronavirus pandemic in 2020. The survival analysis methods used to assess the risk of decline and chance of rise of the indices were: Kaplan–Meier estimator, logit model, and the Cox proportional hazards model. We observed the highest intensity of decline in the European stock exchanges, followed by the American and Asian plus Australian ones (after the fourth and eighth week since the peak). The highest risk of decline was in America, then in Europe, followed by Asia and Australia. The lowest risk was in Africa. The intensity of increase was the highest in the fourth and eleventh week since the minimal value had been reached. The highest odds of increase were in the American stock exchanges, followed by the European and Asian (including Australia and Oceania), and the lowest in the African ones. The odds and intensity of increase in the stock exchange indices varied from continent to continent. The increase was faster than the initial decline.

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Association between milk and yogurt intake and mortality: a community-based cohort study (Yamagata study)

BMC Nutrition ◽

10.1186/s40795-021-00435-1 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Akiko Nakanishi ◽

Erika Homma ◽

Tsukasa Osaki ◽

Ri Sho ◽

Masayoshi Souri ◽

...

Keyword(s):

Proportional Hazards ◽

Proportional Hazards Model ◽

Hazard Analysis ◽

Total Mortality ◽

Cox Proportional Hazards ◽

Cox Proportional Hazards Model ◽

Milk Intake ◽

Community Based ◽

Hazards Model ◽

Kaplan Meier

Abstract Background Dairy products are known as health-promoting foods. This study prospectively examined the association between milk and yogurt intake and mortality in a community-based population. Methods The study population comprised of 14,264 subjects aged 40–74 years who participated in an annual health checkup. The frequency of yogurt and milk intake was categorized as none (< 1/month), low (< 1/week), moderate (1–6/week), and high (> 1/day) intake. The association between yogurt and milk intake and total, cardiovascular, and cancer-related mortalities was determined using the Cox proportional hazards model. Results During the follow-up period, there were 265 total deaths, 40 cardiovascular deaths and 90 cancer-related deaths. Kaplan–Meier analysis showed that the total mortality in high/moderate/low yogurt intake and moderate/low milk intake groups was lower than that in none group (log-rank, P < 0.01). In the multivariate Cox proportional hazard analysis adjusted for possible confounders, the hazard ratio (HR) for total mortality significantly decreased in high/moderate yogurt intake group (HR: 0.62, 95% confidence interval [CI]: 0.42–0.91 for high intake, HR: 0.70, 95%CI: 0.49–0.99 for moderate intake) and moderate milk intake group (HR: 0.67, 95% CI: 0.46–0.97) compared with the none yogurt and milk intake groups. A similar association was observed for cancer-related mortality, but not for cardiovascular mortality. Conclusions Our study showed that yogurt and milk intake was independently associated with a decrease in total and cancer-related mortalities in the Japanese population.

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Clinical impact of regression from sustained to paroxysmal atrial fibrillation: the Fushimi AF registry

European Heart Journal ◽

10.1093/ehjci/ehaa946.0678 ◽

2020 ◽

Vol 41 (Supplement_2) ◽

Author(s):

A Fujino ◽

H Ogawa ◽

S Ikeda ◽

K Doi ◽

Y Hamatani ◽

...

Keyword(s):

Cardiac Death ◽

Proportional Hazards ◽

Proportional Hazards Model ◽

Cox Proportional Hazards ◽

Clinical Impact ◽

Cox Proportional Hazards Model ◽

Cardiac Events ◽

Hazards Model ◽

Adverse Cardiac Events

Abstract Background Atrial fibrillation (AF) commonly progresses from paroxysmal type to sustained type in the natural course of the disease, and we previously demonstrated that the progression of AF was associated with increased risk of clinical adverse events. There are some patients, though less frequently, who regress from sustained to paroxysmal AF, but the clinical impact of the regression of AF remains unknown. Purpose We sought to investigate whether regression from sustained to paroxysmal AF is associated with better clinical outcomes. Methods Using the dataset of the Fushimi AF Registry, patients who were diagnosed as sustained (persistent or permanent) AF at baseline were studied. Conversion of sustained AF to paroxysmal AF during follow-up was defined as regression of AF. Major adverse cardiac events (MACE) were defined as the composite of cardiac death, stroke, and hospitalization for heart failure (HF). Event rates were compared between the patients with and without regression of AF. In patients with sustained AF at baseline, predictors of MACE were identified using Cox proportional hazards model. Results Among 2,253 patients who were diagnosed as sustained AF at baseline, regression of AF was observed in 9.0% (202/2,253, 2.0 per 100 patient-years) during a median follow-up of 4.0 years. Of these, 24.3% (49/202, 4.6 per 100 patient-years) of the patients finally recurred to sustained AF during follow-up. The proportion of asymptomatic patients was lower in patients with regression of AF than those without (with vs without regression; 49.0% vs 69.5%, p<0.01). The percentage of beta-blocker use at baseline was similar between the two groups (37.2% vs 33.8%, p=0.34). The prevalence of patients who underwent catheter ablation or electrical cardioversion during follow-up was higher in patients with regression of AF (catheter ablation: 15.8% vs 5.5%; p<0.01, cardioversion: 4.0% vs 1.4%; p<0.01, respectively). The rate of MACE was significantly lower in patients with regression of AF as compared with patients who maintained sustained AF (3.7 vs 6.2 per 100 patient-years, log-rank p<0.01). Figure shows the Kaplan-Meier curves for MACE, cardiac death, hospitalization for heart failure, and stroke. In patients with sustained AF at baseline, multivariable Cox proportional hazards model demonstrated that regression of AF was an independent predictor of lower MACE (adjusted hazard ratio [HR]: 0.50, 95% confidence interval [CI]: 0.28 to 0.88, p=0.02), stroke (HR: 0.51, 95% CI: 0.30 to 0.88, p=0.02), and hospitalization for HF (HR: 0.50, 95% CI: 0.29 to 0.85, p=0.01). Conclusion Regression from sustained to paroxysmal AF was associated with a lower incidence of adverse cardiac events. Funding Acknowledgement Type of funding source: None

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