Table 1.

Databases Included in the PHARMO Database Network

Database	Data Source	Catchment Areaa	Data Collected	Coding System
General Practitioner (GP) Database (in-house)	Data from electronic patient records registered by GPs of all patients enrolled at the GP	Subnational (~20% of the Dutch population)	Diagnoses Symptoms Laboratory test results Referrals to specialists Healthcare product/drug prescriptions	Diagnoses and symptoms: ICPC Drug prescriptions: WHO ATC Classification System
Out-patient Pharmacy Database (in-house)	Data on all GP or specialist prescribed healthcare products dispensed by the community pharmacies	Subnational (~25% of the Dutch population)	Type of product Date Strength Dosage regimen Quantity Route of administration Prescriber specialty Costs	Dispensings: National product classification WHO ATC Classification System
In-patient Pharmacy Database (in-house)	Data on all drug dispensing from the hospital pharmacy, given during hospitalization	Subnational (~10% of the Dutch population)	Type of product Start and end date of use Strength Dosage regimen Route of administration Prescriber specialty	Dispensings: National product classification WHO ATC Classification System
Clinical Laboratory Database (in-house)	Results of tests performed on clinical specimens, requested by GPs or specialists	Subnational (~5% of the Dutch population)	Date and time of testing Test result Unit of measurement Type of clinical specimen	WCIA Coding System LOINC (partly)
Hospital Database (external)	Data on all hospitalizations for more than 24 hours or for which a bed is required, out-patient visits and high budget impact medication. Data are obtained from the Dutch Hospital Data Foundation.b	Subnational (80% of hospitals in the Netherlands)	Diagnoses In- and out-patient procedures High budget impact medication Admission, discharge and visit dates	Diagnoses: WHO ICD Procedures: DHD registration system for procedures Medication: Dutch classification system
Perinatal Registry (external)	Data on pregnancies, birth and neonatal outcomes. Data are obtained from Perined.c	National	Information on mothers, eg: ● Maternal age ● Obstetric history ● Parity Information on pregnancies, eg: ● Mode of conception ● Mode of delivery Information on children, eg: ● Birth weight ● Gestational age ● Apgar score
Pathology Registry (external)	Excerpts of histological, cytological and autopsy examinations. Data are obtained from PALGA.d	National	Summary of pathology report PALGA diagnosis, structured along five classification axes: 1. Topography 2. Morphology 3. Function 4. Procedure 5. Diseases	Diagnosis codes are a combination of diagnostic terms (localization, acquisition technique, abnormality) and related to the SNOMED coding system.
Cancer Registry (external)	Data on all newly diagnosed cancer cases. Data are obtained from the Dutch Comprehensive Cancer Organization.e	National	Cancer diagnosis Tumor staging Tumor site Morphology Comorbidity at diagnosis Initial treatment	Tumor staging: TNM-classification Tumor site and morphology: WHO ICD-O

Notes: ^aas determined September 2016; ^bwww.dhd.nl; ^cwww.perined.nl; ^dwww.palga.nl; ^ewww.iknl.nl.

Abbreviations: ATC, Anatomical Therapeutic Chemical; DHD, Dutch Hospital Data Foundation; GP, general practitioner; ICD, International Classification of Diseases; ICD-O, International Classification of Diseases for Oncology; ICPC, International Classification of Primary Care; LOINC, Logical Observation, Identifiers, Names and Codes; PALGA, Pathologisch-Anatomisch Landelijk Geautomatiseerd Archief (ie nationwide network and registry of histo- and cytopathology in the Netherlands); SNOMED, Systematized Nomenclature of Medicine; TNM, Tumor Nodes Metastasis Classification of Malignant Tumors; WCIA, Werkgroep Coordinatie Informatie Automatisering (ie Dutch coding system for lab tests); WHO, World Health Organization.