Table 1

Potential data sources used in the OMT registry-based study in the Czech Republic, Norway and Denmark

Czech RepublicNorwayDenmark
Information about OMT user and OMT drugNational Register of Addiction TreatmentThe Norwegian Prescription Database (NorPD)The Danish Registry of Drug Abusers Undergoing Treatment
Information about patients who receive OMT, date of treatment initiation and termination and type of OMT drugPrescription drugs dispensed at pharmacies, all opioids dispensed to outpatients are registered. OMT opioids can be identified by use of ATC codes and Nordic article number. It is estimated that about 90% of the OMT patients are identified using the NorPD.
Use of prescription drugs as proxy of disease is possible in two different situations. For reimbursed drugs, the ICD-10 or ICPC-2 diagnosis code of the disorder that is treated has to be written on the prescription. The other option is to use drugs that only have one indication like for instance insulin for treating diabetes.
Information on patients who are enrolled in outpatient treatment for drug use disorders, including information about patients who receive OMT, date of treatment initiation/termination and type of OMT drug
Information about comorbidity
National Register of Inpatient TreatmentNational Primary Care Reimbursement SystemThe Danish National Prescription Register
Information on every episode of all types of hospitalisations, including information on dates of admission and discharge from hospital. All diagnoses (primary and secondary) and procedures (ICD-10).Diagnosis (ICPC-2) from claims from general practitioners and other health service providers, such as emergency rooms, date of consultationInformation on all individual prescription drugs dispensed through pharmacies to patients outside of institutions such as hospitals and drug treatment facilities
Information System Infections (EPIDAT)The National Patient RegisterThe Danish National Patient Register
Information on all notifications of selected serious infections—verified cases, suspected diseases, carrier of an infection and deaths.Information on all patients receiving hospital-level care in both inpatient and outpatient facilities, and acute and emergency services for mental and somatic illnesses. Primary and secondary diagnoses (ICD-10), date of admission, date of discharge Information on all patients receiving hospital-level care in both inpatient and outpatient facilities, and acute and emergency services for somatic illnesses. Primary and secondary diagnoses (ICD-10), date of admission, date of discharge
National Register of Reimbursed Health Services
Also includes information on prescribed drugs reimbursed within the health insurance system.
Information about death and cause of deathNational General Mortality RegisterCause of Death RegistryCause of Death Registry
Cause of death diagnosis (ICD-10), date of deathCause of death diagnosis (ICD-10), date of deathCause of death diagnosis (ICD-10), date of death
Information about socioeconomic status
Czech Statistical OfficeStatistic NorwayStatistic Denmark
Demographic data, country of birth, education, work situation, income, disability pensionDemographic data, country of birth, education, work situation, income, disability pensionDemographic data, country of birth, education, work situation, income, disability pension
The Danish Psychiatric Central Research Register
Information on all patients receiving hospital-level care in both inpatient and outpatient facilities, and acute and emergency services for mental illnesses. Primary and secondary diagnoses (ICD-10), date of admission, date of discharge
The National Health Insurance Service Registry
Information on individual services undertaken by general practitioners
  • ATC, Anatomical Therapeutic Chemical; ICD-10, International Classification of Diseases, 10th Revision; ICPC-2, International Classification of Primary Care, Second Edition; OMT, opioid maintenance treatment.