Comparison of techniques for handling missing covariate data within prognostic modelling studies: a simulation study

Background  

There is no consensus on the most appropriate approach to handle missing covariate data within prognostic modelling studies. Therefore a simulation study was performed to assess the effects of different missing data techniques on the performance of a prognostic model.     

Intriguing issues of EGFR targeting in head and neck cancer

We have read the recent comprehensive review by Cruz et al.[1] regarding the targeting of receptor tyrosine kinases andtheir therapeutic perspectives in head and neck squamous cellcarcinomas (HNSCC). The major focus of this report was epidermalgrowth factor receptor (EGFR) biology and targeting. However,we feel     

A small sample confidence interval approach to assess individual bioequivalence

The concept of interchangeable pharmaceutical products has been examined in great detail in the literature. Anderson and Hauck proposed a statistical random coefficient model to study 'switchability', and coined the phrase 'individual bioequivalence' which they defined with a probability-based inequality. Since that paper there has been considerable work and discussion. The Food and Drug Administration has recommended the introduction of individual bioequivalence (IBE) and population bioequivalence (PBE) methods in a draft guidance document. The proposal in the draft guidance includes criteria for IBE and PBE and recommends the use of non-parametric bootstrap 95 per cent upper confidence intervals for the conclusion of either IBE or PBE. However, this method requires intensive computations. We have developed an alternative confidence interval procedure to assess IBE by the FDA recommended criteria. This method utilizes Howe's approximation I to a Cornish-Fisher expansion. Our proposed method is applicable to balanced or unbalanced data in a broad class of extended cross-over designs, and can be easily programmed using readily available software.     

A new device for the detection of sponges and other foreign objects left accidentally in the operative field

A new cost-effective device for the detection of sponges and other instruments left accidentally in the surgical field is presented. This device has 100 per cent sensitivity rate in the initial tests. It is extremely simple and rapid and does not require the use of radiation or other harmful techniques.