Comparison of parametric and semi-parametric models with randomly right-censored data by weighted estimators: Two applications in colon cancer and hepatocellular carcinoma datasets

2021 ◽  
pp. 096228022110616
Author(s):  
İsmail Yenilmez ◽  
Ersin Yılmaz ◽  
Yeliz Mert Kantar ◽  
Dursun Aydın
Keyword(s):  
Regression Models ◽  
Cox Regression ◽  
Parametric Models ◽  
Parametric Approach ◽  
Right Censored Data ◽  
Kaplan Meier ◽  
Smoothing Kernel ◽  
Gamma Distributions ◽  
Right Censorship ◽  
Approach Method

In this study, parametric and semi-parametric regression models are examined for random right censorship. The components of the aforementioned regression models are estimated with weights based on Cox and Kaplan–Meier estimates, which are semi-parametric and nonparametric methods used in survival analysis, respectively. The Tobit based on weights obtained from a Cox regression is handled as a parametric model instead of other parametric models requiring distribution assumptions such as exponential, Weibull, and gamma distributions. Also, the semi-parametric smoothing spline and the semi-parametric smoothing kernel estimators based on Kaplan–Meier weights are used. Therefore, estimates are obtained from two models with flexible approaches. To show the flexible shape of the models depending on the weights, Monte Carlo simulations are conducted, and all results are presented and discussed. Two empirical datasets are used to show the performance of the aforementioned estimators. Although three approaches gave similar results to each other, the semi-parametric approach was slightly superior to the parametric approach. The parametric approach method, on the other hand, yields good results in medium and large sample sizes and at a high censorship level. All other findings have been shared and interpreted.

scholarly journals Comparison of Efficacy Between Triamcinolone Acetonide and Triamcinolone Hexacetonide for Intraarticular Therapy in Juvenile Idiopathic Arthritis: A Retrospective Analysis

2021 ◽  
Author(s):  
Deirdre De Ranieri ◽  
Angela Chun ◽  
Lutfiyya Muhammad
Keyword(s):  
Regression Models ◽  
Cox Regression ◽  
Mixed Effects ◽  
Rank Test ◽  
Triamcinolone Hexacetonide ◽  
Drug Of Choice ◽  
Log Rank Test ◽  
Kaplan Meier ◽  
Time To Relapse ◽  
Corticosteroid Injections

Abstract Background There are many FDA-approved corticosteroid preparations available for intra-articular injection, however triamcinolone hexacetonide is not one of them. It was the intraarticular drug of choice among pediatric rheumatologists up until approximately a decade ago, when production of this medication ceased. It can be obtained in the United States and Canada via importation from Europe, but it is not FDA-approved at this time. We wish to compare the duration of remission of intraarticular triamcinolone hexacetonide (TH) with that of triamcinolone acetonide (TA) in children with Juvenile Idiopathic Arthritis (JIA) and demonstrate its safety in this population. Methods This retrospective chart review included 39 patients with JIA who received intraarticular corticosteroid injections (IACIs) from September 2018 to September 2019. These patients were reviewed and their life-time injections with either TH (41 joints) or TA (124 joints) was noted through May 30, 2021. Patients with concomitant systemic therapy initiation were excluded. The primary outcome was time to relapse. Relapse was defined by the presence of arthritis on physical examination by an attending rheumatologist. Kaplan-Meier curves and a log-rank test were constructed to compare the probability of time to relapse between IACI injections. Additionally, mixed effects cox regression models were constructed to account for multiple injections per participant. Results Kaplan-Meier estimator of median relapse time in months was higher for TH. Based on the log-rank test, TA joints had a higher probability of experiencing a relapse during the study time (p-value < 0.001). The hazard of time to relapse was reduced when comparing TH to TA in both unadjusted and adjusted mixed effects cox regression models (unadjusted hazard ratio (95% confidence interval): 0.184 (0.089, 0.381); adjusted hazard ratio (95% confidence interval): 0.189 (0.092, 0.386)). Conclusions TH has longer duration of action than TA and is associated with less systemic side effects. It should be considered the drug of choice for intraarticular corticosteroid injections in children with JIA.

scholarly journals A comparison of the prognostic significance of changes in NT-proBNP levels in HFrEF and HFpEF.

2021 ◽  
Author(s):  
Nishant Sahni ◽  
Umesh Sharma ◽  
Rashi Arora
Keyword(s):  
Regression Models ◽  
Cox Regression ◽  
Survival Rates ◽  
Prognostic Significance ◽  
Rank Test ◽  
Log Rank Test ◽  
Kaplan Meier ◽  
Regional Health Care ◽  
Comorbidity Scores ◽  
Blood Pressures

Background: Rising NT-proBNP are associated with reduced survival patients with HFrEF. However, it remains to be conclusively and formally demonstrated that the temporal trend in NT-proBNP level carries prognostic significance in HFpEF. Objective: To determine whether there is an association between rising NT-proBNP levels and 6-month survival in patients with HFpEF and HFrEF. Methods: We examined a cohort of 5203 patients to 5 hospitals in a regional health care system — who had at least one admission to the hospital with diagnoses of heart failure over a 3-year period. Kaplan-Meier survival curves were constructed for patients with downtrending (>25% net decrease), stable or uptrending (>25% net increase) NT-proBNP levels in HF, HFpEF and HFrEF patients. The log-rank test was used to test for differences in 6-month survival amongst the groups. Multivariate extended Cox regression models were constructed for 6-month survival with NT-proBNP as a time-varying covariate. Age, albumin, sex, race, serum creatinine, systolic and diastolic blood pressures and Charlson comorbidity scores at baseline were used as covariates in the model. Separate analyses were done for HFpEF and HFrEF patients. Results: HFpEF and HFrEF patients with up-trending levels had significantly lower 6-month survival rates than patients with downtrending or stable NT-proBNP levels. A doubling of the NT-proBNP level in patients was significantly associated with reduced 6-month survival in patients with in both subgroups of HF, HFpEF and HFrEF (HFpEF-HR: 1.53(1.49-2.57), HFrEF HR: 1.45(1.43-1.48) after adjusting for covariates.

scholarly journals The Neutrophil-to-lymphocyte Ratio at the Time of Admission: A New Prognostic Indicator for Hospital Mortality of Trauma Patients

2021 ◽  
Author(s):  
Hamed Fouladseresht ◽  
Shahram Bolandparvaz ◽  
Hamid Reza Abbasi ◽  
Hossein Abdolrahimzadeh Fard ◽  
Shahram Paydar
Keyword(s):  
Survival Analysis ◽  
Hospital Mortality ◽  
Regression Models ◽  
Cox Regression ◽  
Prognostic Indicator ◽  
Neutrophil To Lymphocyte Ratio ◽  
Trauma Patients ◽  
Lymphocyte Ratio ◽  
Kaplan Meier ◽  
Time Of Admission

The elevated neutrophil-to-lymphocyte ratio (NLR) is associated with poor clinical outcomes, especially in pro-inflammatory states such as surgical injuries and severe hemorrhages. Therefore, it was hypothesized whether NLR value at the time of admission could be a prognostic indicator of hospital mortality in trauma patients. This retrospective cohort study was conducted on 865 trauma patients referred to Rajaee Hospital between April 2016 and July 2019. The NLR value was calculated at the time of admission, and receiver operating characteristics (ROC) curve analysis was used to determine the cut-off point value of admission NLR related to hospital mortality of trauma patients. Furthermore, Kaplan-Meier survival analysis and Cox regression models have been applied to determine the effectiveness and prognostic potential of the admission NLR in the hospital mortality of trauma patients. The median age of the trauma patients was 32 years with an interquartile range (IQR) of 23 to 48 years, and most of them were male (83.9%). Also, trauma patients had a median injury severity score (ISS) of 9 (IQR=4-16) and a median Glasgow coma scale (GCS) of 14 (IQR=9-15). The cut-off value for admission NLR was 5.27 (area under the curve: 0.642, 95%CI: 0.559-0.726, p=0.001). In Kaplan-Meier survival analysis, the admission NLR>5.27 was an indicator of hospital mortality in trauma patients (p=0.001). Multivariate Cox regression models demonstrated that trauma patients with an admission NLR>5.27 had a 2.33-fold risk of hospital mortality (hazard ratio=2.33, 95%CI: 1.02-5.38, p=0.041). Furthermore, the admission NLR>5.27 was associated with a higher risk of hospital mortality in trauma patients with age≥65 years, systolic blood pressure≤90 mmHg, blood potassium>4.5 mmol/L, blood sodium>144 mEq/L, blood potential hydrogen (pH)≤7.28, GCS≤8, ISS>24 and blood base excess≤-6.1 mEq/L. The NLR value greater than 5.27 at the time of admission was associated with poorer outcomes, and it can be considered an independent prognostic indicator of hospital mortality in trauma patients.

scholarly journals A large-cohort retrospective study of metastatic patterns and prognostic outcomes between inflammatory and non-inflammatory breast cancer

2020 ◽  
Vol 12 ◽  
pp. 175883592093267
Author(s):  
Zheng Wang ◽  
Hui Wang ◽  
Xinyuan Ding ◽  
Xiaosong Chen ◽  
Kunwei Shen
Keyword(s):  
Breast Cancer ◽  
Epidermal Growth Factor Receptor ◽  
Lymph Node ◽  
Inflammatory Breast Cancer ◽  
Regression Models ◽  
Cox Regression ◽  
Growth Factor Receptor ◽  
Kaplan Meier ◽  
Metastatic Patterns ◽  
Epidermal Growth

Background and aims: Breast cancer-related death is attributable mainly to metastasis. Inflammatory breast cancer (IBC) is an infrequent subtype of breast cancer that shows a relatively high rate of metastasis. In this study, we aimed to compare the metastatic patterns and prognostic outcomes of IBC and non-inflammatory breast cancer (non-IBC). Methods: We extracted data between 2010 and 2014 from the Surveillance, Epidemiology and End Results (SEER) database. The Chi-square test and Fisher’s exact test were used to compare the categorical parameters among different groups. Logistic regression was applied for multivariate analysis. The Kaplan–Meier method and multivariate Cox regression models were performed to analyze prognosis. Results: We enrolled 233,686 breast cancer patients between 2010 and 2014 in our research, including 2806 IBC and 230,880 non-IBC patients. Compared with the non-IBC group, the IBC group tended to have a higher incidence of the human epidermal growth factor receptor 2 positive (HER2+) and triple-negative breast cancer (TNBC) subtypes, older age, a higher rate of unmarried status, a lower incidence of black race, poorer tumor differentiation, larger tumor sizes, and a higher frequency of regional lymph node invasion. IBC and non-IBC shared similar trends in molecular subtypes among different metastatic organs. The percentage of the hormone receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2–) subtype decreased gradually in patients with lung (IBC 42.5%, non-IBC 55.7%), distant lymph node (IBC 41.5%, non-IBC 54.6%), liver (IBC 31.1%, non-IBC 46.7%), and brain (IBC 30.6%, non-IBC 47.9%) metastases compared with that in patients with bone (IBC 50.8%, non-IBC 69.0%) metastasis in both cohorts. In both the IBC and non-IBC cases, the proportion of visceral metastases increased in the TNBC subtype, especially brain metastasis (IBC 26.4%, non-IBC 21.2%), which had the largest increase. The frequencies of all sites (bone, lung, liver, brain, and distant lymph node) in IBC were much higher than those in non-IBC (bone: IBC 21.1%, non-IBC 3.0%; lung: IBC 11.4%, non-IBC 1.4%; liver: IBC 9.6%, non-IBC 1.2%; brain: IBC 2.6%, non-IBC 0.3%; distant lymph node: IBC 12.9%, non-IBC 1.0%). The most frequent bi-site metastasis was the bone and liver (IBC 2.5%, non-IBC 0.3%), and the most frequent tri-site combination was the bone, lung, and liver (IBC 1.1%, non-IBC 0.2%). Kaplan–Meier curves and multivariate Cox regression models suggested that the IBC cohort had poorer overall survival [hazard ratio (HR) 1.602, 95% confidence interval (CI) 1.496–1.716, p < 0.001] and breast cancer-specific survival (HR 1.511, 95% CI 1.402–1.628, p < 0.001) than the non-IBC cohort. Furthermore, univariate and multivariate analyses indicated that IBC was an independent prognostic factor in patients with different metastatic sites. Conclusion: IBC and non-IBC patients presented with different metastatic frequencies, clinical features and prognostic outcomes. Our findings provide more information for therapeutic decision making and clinical study designs.

The Impact Of Waist Circumference And Diabetes On Incident Of Cardiovascular Death During 9 Years Of Follow Up In General Population

2021 ◽  
Author(s):  
Man Li ◽  
Shu-xia Wang ◽  
Yong-kang Su ◽  
Jin Sun ◽  
An-hang Zhang ◽  
...  
Keyword(s):  
Waist Circumference ◽  
General Population ◽  
Regression Models ◽  
Prognostic Value ◽  
Cox Regression ◽  
Cardiovascular Death ◽  
Kaplan Meier ◽  
Obesity And Diabetes ◽  
Increased Risk

Abstract Background: It has been reported that obesity and diabetes are both the risk factors for the development of cardiovascular diseases (CVD). However, recent articles reported that compared with BMI, waist circumference (WC) can better reflect obesity, more closely related to visceral fat tissue which is positively associated with an increased risk of cardiovascular death. Moreover, few studies have both investigated the prognostic value of both WC and diabetes during a long-term follow up. We aimed to investigate whether higher level of WC measurements and diabetes were able to predict cardiovascular mortality in general population.Methods: In this prospective cohort study, a total of 1521 consecutive subjects free of clinical cardiovascular disease were included. The end point was cardiovascular death. The Kaplan-Meier method and Cox regression models were used to evaluate the cumulative risk of outcome at different WC levels with or without diabetes.Results: During a median follow up of 9.2 years, there were 265 patients had the occurrence of cardiovascular death. Kaplan-Meier survival estimates indicated that the patients with higher levels of WC (WC>94cm) coexist with diabetes had significantly increased risk of cardiovascular death (log-rank p＜0.05). After adjustment for potential confounders, multiple COX regression models showed that the incidence of cardiovascular death was significantly higher when patients with high WC coexisted with DM (HR 3.78; 95% CI: 3.35–3.98; p＜0.001).Conclusion: Patients with high WC and diabetes represent a high-risk population for cardiovascular death. WC and diabetes may provide incremental prognostic value beyond traditional risks factors.

scholarly journals Use of Medications by Breastfeeding Women in the 2015 Pelotas (Brazil) Birth Cohort Study

2020 ◽  
Vol 17 (2) ◽  
pp. 568 ◽  
Author(s):  
Bárbara Heather Lutz ◽  
Diego Garcia Bassani ◽  
Vanessa Iribarrem Avena Miranda ◽  
Marysabel Pinto Telis Silveira ◽  
Sotero Serrate Mengue ◽  
...  
Keyword(s):  
Regression Models ◽  
Cox Regression ◽  
Medication Use ◽  
Population Based ◽  
Birth Cohort Study ◽  
Ministry Of Health ◽  
Adverse Side Effects ◽  
Kaplan Meier ◽  
Duration Of Breastfeeding ◽  
Risk Categories

Background: This study describes medication use by women up to 3 months postpartum and evaluates the association between medication use by women who were still breastfeeding at 3 months postpartum and weaning at 6 and 12 months. Methods: Population-based cohort, including women who breastfed (n = 3988). Medications were classified according to Hale’s lactation risk categories and Brazilian Ministry of Health criteria. Duration of breastfeeding was analysed using Cox regression models and Kaplan-Meier curves, including only women who were still breastfeeding at three months postpartum. Results: Medication use with some risk for lactation was frequent (79.6% regarding Hale’s risk categories and 12.3% regarding Brazilian Ministry of Health criteria). We did not find statistically significant differences for weaning at 6 or 12 months between the group who did not use medication or used only compatible medications and the group who used medications with some risk for lactation, according to both criteria. Conclusions: Our study found no association between weaning rates across the different breastfeeding safety categories of medications in women who were still breastfeeding at three months postpartum. Therefore, women who took medications and stopped breastfeeding in the first three months postpartum because of adverse side-effects associated with medications could not be addressed in this analysis.

Sex differences in implantable cardiac defibrillator therapy according to arrhythmia detection times

Heart ◽  
2019 ◽  
Vol 106 (7) ◽  
pp. 520-526 ◽  
Author(s):  
Maurizio Gasparini ◽  
Axel Kloppe ◽  
Maurizio Lunati ◽  
Niraj Varma ◽  
Jose B Martinez-Ferrer ◽  
...  
Keyword(s):  
Sex Differences ◽  
Ventricular Arrhythmias ◽  
Regression Models ◽  
Cox Regression ◽  
Implantable Cardiac Defibrillator ◽  
Clinical Trial Registration ◽  
Arrhythmia Detection ◽  
Post Hoc Analysis ◽  
Kaplan Meier ◽  
Post Hoc

ObjectiveIn implantable cardiac defibrillators (ICDs), long-detection times safely reduce unnecessary and inappropriate therapies. We aimed to evaluate ICD treatment of ventricular arrhythmias in women, compared with men, also taking into account ICD detection.MethodsThe Advance III trial randomised patients implanted with an ICD for primary or secondary prevention in two arms—long and nominal ventricular arrhythmias detection times before therapy delivering (number of intervals needed to detect (NID) 30/40 and 18/24, respectively). The main endpoint of this post hoc analysis was the incidence of ICD therapies evaluated through Kaplan-Meier method and univariate Cox regression models.ResultsOverall, 1902 patients (304 women, 65±11 years) were randomised. Women showed a lower risk of ICD therapy (HR 0.63, 95% CI 0.43 to 0.93, p=0.022); this difference was observed only in the long-detection arm (HR 0.37, p=0.013) and not in the short detection arm (HR 0.82, p=0.414). No significant sex differences were observed concerning inappropriate therapies and mortality rate. Long-detection settings significantly reduced overall ICD therapies and appropriate ICD therapies, both in women (overall HR 0.31, p=0.007; appropriate HR 0.33, p=0.033) and in men (overall HR 0.69, p=0.006; appropriate HR 0.73, p=0.048).ConclusionsIn patients with ICDs, the strategy of setting a long-detection time to treat ventricular arrhythmias (NID 30/40) reduces overall delivered therapies, both in women and men, when compared with nominal setting (NID 18/24). The reduction was significantly higher in women. Overall, women were less likely to experience ICD therapies than men; this result was only observed in the long-detection arm.Clinical trial registrationNCT00617175.

scholarly journals Downregulation of Macrophage-Derived T-UCR uc.306 Associates with Poor Prognosis in Hepatocellular Carcinoma

2017 ◽  
Vol 42 (4) ◽  
pp. 1526-1539 ◽  
Author(s):  
Hong-Lin Luo ◽  
Jie Chen ◽  
Tao Luo ◽  
Fei-Xiang Wu ◽  
Jun-Jie Liu ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Regression Models ◽  
Wnt Pathway ◽  
Cox Regression ◽  
M1 Macrophages ◽  
Kaplan Meier ◽  
Tumor Tissues ◽  
M1 Phenotype ◽  
Lower Expression

Background/Aims: Increasing evidence suggests that T-UCRs are involved in the development of cancer. In this study, we evaluated the role of a macrophage-derived T-UCR, uc.306, in the prognosis of hepatitis B (HBV)-related hepatocellular carcinoma (HCC). Methods: The uc.306 was obtained by screening microassay data obtained during the polarization of U937 cells from the M2 to M1 phenotype. Uc.306 and macrophage molecule markers were detected by qPCR. Immunohistochemical (IHC) assays were used to examine the M1/M2 status of 90 paired HCC tissues. Kaplan-Meier tests and multivariable Cox regression models were used to analyze predictive confidences, survival, and risk factors. Results: In total, 2,977 differentially expressed T-UCRs were obtained, of which 257 showed fold changes >1.5. The uc.306 was upregulated in M1 cells and was predicted to be involved in the Wnt pathway. The IHC results showed that M1 macrophages (CD68+) were present in the para-tumor tissues, while the M2 phenotype (CD163+) was mainly in the HCC tissues. Uc.306 had a lower expression in the HCC tissues than in that of the para-tumor tissues in 30 paired HCC training sets (P < 0.0001), and 252 paired HCC testing sets (P < 0.0001). Low expression of uc.306 was significantly associated with a shorter overall survival (P < 0.05). Conclusions: The uc.306 may be a promising biomarkerfor HBV-related HCC, providing a novel marker for the prognosis of HCC.

scholarly journals Proton Pump Inhibitor Taking Associates with Higher All-Cause Mortality and CV Events in Peritoneal Dialysis Patients

2020 ◽  
Author(s):  
Yingsi Zeng ◽  
Lingling Liu ◽  
Liya Zhu ◽  
Xiaojiang Zhan ◽  
Fenfen Peng ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Proton Pump ◽  
Regression Models ◽  
Cox Regression ◽  
Adverse Outcomes ◽  
Rank Test ◽  
Log Rank Test ◽  
Kaplan Meier ◽  
All Cause Mortality ◽  
The Impact

Abstract Background: A long period of inappropriate proton pump inhibitors (PPI) treatment have been proved to be associated with adverse prognosis in general population and hemodialysis (HD) patients. This study was conducted to clarify the impact of PPI taking on mortality and adverse cardiovascular (CV) events in peritoneal dialysis (PD) patients.Methods: This is a retrospective study. We enrolled 904 patients from two PD centers, included 211 patients on PPI treatment and 618 patients not taking PPIs. Kaplan-Meier curves were used to identify the incidence of adverse outcomes. Multivariate Cox regression models and inverse probability of treatment weighting (IPTW) were applied to analyze hazard ratios (HRs) for adverse outcomes. Results: During follow-up, 162 deaths and 102 CV events were recorded. Kaplan-Meier curve demonstrated all-cause mortality (log-rank test P=0.018) and CV events (log-rank test P=0.024) were significantly higher in PPI usage group. Multivariate COX regression models and IPTW showed that PPI taking was an indicator for all-cause mortality (HR=1.33, 95%CI=1.07-1.65, P=0.010) and CV events (HR=1.81, 95%CI=1.38-2.38, P<0.001). Conclusions: PPI usage associates with higher all-cause mortality and CV events in PD patients. Clinicians are supposed to be more careful when using PPI and need to master the indications more rigorously in patients receiving PD treatment.

scholarly journals CCL2 is associated with metastasis and poor prognosis of bladder cancer

2019 ◽  
Author(s):  
wei gao ◽  
qiwang zhang ◽  
lianhua zhang ◽  
qiang liu ◽  
xuehui duan ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Cancer Progression ◽  
Regression Models ◽  
Cox Regression ◽  
Tumor Grade ◽  
The Novel ◽  
Kaplan Meier ◽  
Ccl2 Expression ◽  
Immune Factor ◽  
Cancer Types

Abstract Background: Chemokine (C-C motif) ligand 2 (CCL2) is an important immune factor, which may be important in cancer progression by promoting proliferation, invasion metastasis and the tumor microenvironment. Recent researches have demonstrated that overexpression of CCL2 is associated with unfavorable prognosis in various cancer types. In this study, we aim to determine the prognostic value of CCL2 expression in patients with bladder cancer (BC). Methods: We retrospectively enrolled 154 patients with bladder cancer at Renji Hospital, Shanghai Jiaotong University between 2005 and 2007. CCL2 expression was assessed by immunohistochemical staining and its association with clinicopathologic features and prognosis were evaluated. Kaplan-Meier method was applied to compare survival curves. Cox regression models were fitted to analyze the effect of prognostic factors on Overall survival (OS). Results: CCL2 protein had high expression in 73 of 154 cases of BC (47%). CCL2 overexpression was significantly associated with tumor grade (P<0.001), stage (P=0.005), and lymph node metastasis (P=0.025). The Kaplan–Meier survival analysis demonstrated that CCL2 expression was significantly associated with DSS and OS (both P< 0.001). Multivariate analysis further demonstrated that CCL2 was an independent prognostic factor for patients with BC. Conclusion: CCL2 might be a new molecular marker to predict the prognosis of patients with BC. The novel risk classification based on combining CCL2 and TNM is more reliable than using either alone.

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