Effect of computerised prescribing on use of antibiotics

To the Editor: I would like to comment on the recent article by Newby et al.1 They conclude that the default settings in computerised prescription packages result in a significant increase in the use of antibiotics. I do not believe this is a valid conclusion.

As the authors state that 85% of general practitioners generating computerised prescriptions are using Medical Director (MD), it is reasonable to assume that the default settings in MD would contribute significantly to this effect if their conclusion is correct.

I have installed and tested MD v.2.3 from February 2000, MDW v.1.85 from February 2000 and MD v.2.4 from May 2000. These were the versions that would have been in use at the time of this study.

All versions default to printing "once-only" prescriptions without repeats. In fact, when a "once-only" prescription has been selected, MD's default behaviour is to display a prompt for the quantity and repeats with the default repeats field set to "0".

This is very easy to verify simply by installing a copy of MD onto a "clean" computer and printing some scripts. As this was evidently not done, it casts doubt on the quality of the whole study. How can the authors reach a conclusion about the effect of the default settings in computerised prescription packages without first ascertaining what those default settings are? They appear to have assumed that the default behaviour of all computer prescription packages is to print the maximum number of repeats allowed by the Pharmaceutical Benefits Scheme. No attempt appears to have been made to verify whether this is the case.

Whatever the reason for the observed increase in repeat antibiotic prescriptions, it is incorrect to conclude that it is due to the default settings in computerised prescribing packages. No discussion of other possible explanations for the observed increase is presented and it appears as though the data have been used to support a conclusion that had been decided before the study was commenced.