Authors’ reply to Hamilton

Hamilton highlights important points.12 If the concern is that the patient has an underlying condition such as asthma, the self controlled case series (SCCS) design incorporates a within person comparison. So, if the patient had asthma for five years, this is held constant and is controlled for in the analysis. However, if the patient developed asthma after having been given the corticosteroids, having concurrent asthma was not an “indication” for prescribing the drug. The SCCS design is very powerful in controlling for underlying comorbidities (and interactions among comorbidities) in a patient. In addition, the pattern of adverse events persisted across the various indications for treatment, showing consistency regardless of …