Reply to Pramesh et al: Shuttle walk distance and lung cancer surgical outcome Free

The use of Student's t-test to predict the surgical outcome from shuttle distance was advised by our MRC biostatistician (Cambridge), Dr Linda Sharples. This was to attempt to find out the statistical correlation between poor surgical outcome and shuttle walk distance as a continuous measure. We recognise that this may be of limited usefulness in the current lung cancer population as it is quite heterogeneous, although it was more useful in the more homogenous subsets such as male or pneumonectomy patients. However as we agree that this statistical measure may have overall limited use in clinical practice, we did investigate to see whether we could identify a lower cut off value of shuttle walk to identify patients at high risk from surgery [1]. This is reported in the final paragraph of the results section. As can be seen, although surgical outcome tended to be worse at lower levels of shuttle walk, there was no overall lower threshold identified below which surgical outcome could reliably be predicted to be unacceptable, except for men undergoing pneumonectomy in whom there was an 88% chance of a poor outcome if shuttle walk was less than 250m.

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