In this cohort from Aberdeen, 1371 children were assessed at 2 years and their asthma symptoms subclassified into rattle, purr and whistle.  At five years there was a significant difference between the groups in terms of treatment with asthma medication.  Here.

It’s worth adding a line or two to this.  It isn’t often that you see a paper which actually attempts to alter our clinical skills – I’d say that the vast majority of papers published by ADC look at treatments or tests.  This paper looks at children who wheeze and says “Well, wheeze is more complicated than that”.  It then defines rattle, purr and whistle.  I’d be interested what people think of these three; I have the most trouble with purr.  The question will be:  Can you reproduce these categories yourself, and if you can, will you find the same things as this group?