Data-Based Nonparametric Estimation of the Hazard Function with Applications to Model Diagnostics and Exploratory Analysis

1984 ◽  
Vol 79 (385) ◽  
pp. 174-182 ◽  
Author(s):  
Martin Abba Tanner ◽  
Wing Hung Wong
2020 ◽  
Author(s):  
Abhishek Goyal ◽  
Saurabh Saigal ◽  
Ankur Joshi ◽  
Dodda Brahmam ◽  
Yogesh Niwariya ◽  
...  

Introduction: Steroids have shown its usefulness in critically ill COVID19 patients. However time of starting steroid and dose tailored to severity remains a matter of inquiry due to still emerging evidences and wide-ranging concerns of benefits and harms. We did a retrospective record analysis in an apex teaching hospital ICU setting to explore optimal doses and duration of steroid therapy which minimizes the hazard of death. Methodology: 114 adults with COVID19-ARDS admitted to ICU between 20thMarch-15thAugust2020 were included in chart review. We did preliminary exploratory analysis(rooted in steroid therapy matrix categorized by dose and duration) to understand the effect of several covariates on survival. This was followed by univariate and multivariate Cox proportion hazard regression analysis and model diagnostics. Results: Exploratory analysis and visualization indicated age, optimal steroid, severity (measured in P/F) of disease and infection status as potential covariates for survival. Univariate cox regression analysis showed significant positive association of age>60 years{2.6 (1.5-4.7)} and protective effect of optimum steroid{0.38(0.2-0.72)} on death (hazard) in critically ill patients. Multivariate cox regression analysis after adjusting effect of age showed protective effect of optimum steroid on hazard defined as death {0.46(0.23-0.87),LR=17.04,(p=2e-04)}.The concordance was 0.70 and model diagnostics fulfilled the assumption criteria for proportional hazard model. Conclusion: Optimal dose steroid as per defined optimum(<24 hours and doses tailored to P/F at presentation) criteria can offer protective effect from mortality which persists after adjusting for age. This protective effect was not found to be negatively influenced by the risk of infection.


Bernoulli ◽  
2009 ◽  
Vol 15 (4) ◽  
pp. 1010-1035 ◽  
Author(s):  
Hanna K. Jankowski ◽  
Jon A. Wellner

1999 ◽  
Vol 28 (10) ◽  
pp. 2294-2331 ◽  
Author(s):  
Graciela Estévez-Pérez ◽  
Alejandro Quintela-del-Río

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