The data were collected on a monthly basis from billing centres that processed all reimbursed prescriptions from pharmacies based on the date of redemption at the counter.
The children were followed from date of birth until the date of redemption of an ADHD prescription, receipt of an ADHD diagnosis, emigration, death or the end of follow-up on 31 December 2010, whichever came first.
From this register, we had information on the date of redemption of the prescription and substance classified according to the anatomical-therapeutic-chemical (ATC) system.
Not all mortgages taken out between these dates are affected – just those with terms and conditions which state that interest will only be charged up until the date of redemption.
For each patient we assessed if spirometry was registered in an 18-month period counting from 6 months before to 12 months after the date of the first redemption of obstructive lung medication.
19 On redemption (that is, the filling of a prescription), information from each prescription, including date of redemption, is stored with the purpose of financial compensation.
Information on redeemed prescriptions was retrieved from the National Prescription Register, which holds information on date of redemption, quantity, strength and form.
For each redeemed prescription, the following information is recorded: date of redemption, active substance (description and Anatomical Therapeutic and Chemical ATC classification code [ 31]), brand, quantity, strength, dispensed form, number of units and number of refills.
The register contains type of drug (International Anatomical Therapeutic Coding (ATC)), date of redemption, quantity dispensed and strength.
Data from NorPD contains drug redemptions according to physicians' prescriptions in Norway from 2004 on anonymous patient identifications, patients' age, gender, county of residence, physician's specialty, date of redemption, numbers of defined daily doses (DDDs) redeemed and ATC-category (Anatomical Therapeutic Chemical classification system 12 13) of the drug.
