Although this approach has several drawbacks, it does provide natural performance metrics such as positive and negative predictive values to enable unambiguous assessments.
Methods: We compare the survival-time prediction and survival-time threshold approaches to analyzing cancer survival studies.
We review and compare common performance metrics for the two approaches. We present new randomization tests and cross-validation methods to enable unambiguous statistical inferences for several performance metrics used with the survival-time prediction approach. We consider five survival prediction models consisting of one clinical model, two gene expression models, and two models from combinations Selleck CA4P of clinical and gene expression models.
Results: A public breast cancer dataset was used to compare several performance metrics using five prediction models. 1) For some prediction models, the hazard ratio from fitting a Cox proportional hazards model was significant, but the two-group
comparison was insignificant, and vice versa. 2) GSK J4 manufacturer The randomization test and cross-validation were generally consistent with the p-values obtained from the standard performance metrics. 3) Binary classifiers highly depended on how the risk groups were defined; a slight change of the survival threshold for assignment of classes led to very different prediction results.
Conclusions: 1) Different performance metrics for evaluation of a survival prediction model may give different conclusions in
its discriminatory ability. 2) Evaluation using a high-risk versus low-risk group comparison depends on the selected risk-score threshold; a plot of p-values from all possible thresholds can show the sensitivity of the threshold selection. 3) A randomization test of the significance of Somers’ rank correlation can be used for further evaluation of performance Ganetespib purchase of a prediction model. 4) The cross-validated power of survival prediction models decreases as the training and test sets become less balanced.”
“Inclusion body myositis is a slowly progressive myopathy affecting predominantly the middle-aged and older patient population. It is a major form of the idiopathic inflammatory myopathies which are chronic systemic autoimmune diseases characterized by symmetrical proximal muscle weakness. Unfortunately, there is no effective therapy yet; however, the early diagnosis is essential to provide treatment options which may significantly slow the progression of the disease. In our case-based clinicopathological study the importance of the close collaboration between the clinician and the neuropathologist is emphasised.”
“BackgroundCurrent data on the management of patients in cardiac rehabilitation (CR) after an acute hospital stay due to ST-segment elevation or non-ST segment elevation acute coronary syndromes (STE-ACS or NSTE-ACS) are limited.