| | Pharmacoepidemiological Studies of Polypharmacy. |
 | | The main therapeutic class (second level of the ATC code) was used as indicator of the type of health problem. |
 | | Drugs were categorised by their anatomical therapeutical chemical (ATC) classification code, and differentiated to the fifth level of the ATC code (eg furosemide: CO3C A01). |
 | | The identification code of the prescriber was also registered at the pharmacies, but this information was not important for the reimbursement of drugs, and if the pharmacies were not careful with the registration of the prescriber, it might carry a risk of prescriber-misclassification. |
| www.sdu.dk /health/IPH/genpract/staff/lbjerrum/PHD/PHD.HTM (16853 words) |