Editorial comment on 'efficacy of a mobile lithotripsy service: A one-year review of 222 patients'

摘要

As you correctly say, the Hosmer-Lemeshow calibration statistics are very sensitive to the size of the study population, with large numbers of patients resulting in unreliable calibration. This fact is applicable to study populations larger than 5,000 patients, which was indeed the case in our study. We have tested the SAPS 3 in another trial on 4,054 patients of the years 2007-2009. In this analysis the score achieved similar results to that published in our study. That is the reason why we have not shifted to an alternative approach in the calibration statistics, for example the method according to Grunkemeier et al.j which analyses the observed/expected ratio. Furthermore a large population must not always affect the Hosmer-Lemeshow calibration statistics. Nashef et al. achieved good results with this method on 13,302 patients when they published the EuroSCORE (3).