In the abstract, authors write:
........Results Of 1 548 945 adults, 327 452 (21.1%) received at least one outpatient prescription for short term use of oral corticosteroids over the three year period...........Incidence rate ratios for adverse events within 30 day and 31-90 day risk periods after drug initiation........
What our query is, as follows:
At least one prescription means there could be more than one prescription in 3 years study period. But, if the other prescriptions are given within the follow up period of 90 days, to note the adverse events, then one can get intrigued that more than one prescription can have cumulative effect on the outcome (adverse event) compared to just one prescription.
Authors may clarify this issue.
Competing interests: No competing interests