TABLE 1.
Data sources for exposure and outcome variables used in the record linkage
| Data source | Content | Purpose | Example variables |
|---|---|---|---|
| Chemotherapy Electronic Prescribing System (CEPAS) 26 | Systemic anti‐cancer therapy (SACT) prescribing for all NHS patients a | Identification of study population; medicine exposure | SACT medicine, dose, indication, treatment dates |
| Scottish Cancer Registry (SMR06) 27 | New cancer diagnoses b | Disease‐related details | Diagnosis (ICD‐10), date of diagnosis, Gleason score |
| ARIA 26 | Radiotherapy records | Previous/subsequent treatment | Dose/fraction, indication, appointment date |
| Scottish Care Information (SCI store) 27 | Laboratory test results | Baseline bloods; PSA levels | Type of test, test date, value |
| Scottish Morbidity Records, Inpatient and Day Case dataset (SMR01) 27 | Episode level data on acute hospital admissions | Comorbidities; previous/subsequent treatment | Diagnosis (ICD‐10), admission date, length of stay, procedures undertaken |
| Scottish Morbidity Records, Outpatient Attendance dataset (SMR00) 27 | Episode level data on outpatient clinic attendances | Comorbidities; previous/subsequent treatment | Diagnosis (ICD‐10), appointment date, procedures undertaken |
| Prescribing Information System (PIS) 28 | Primary care prescribing for all NHS patients c | Comorbidities; previous/subsequent treatment | Medicine, dose, quantity, prescription dates |
| National Records of Scotland (NRS) 27 | Registration of life events | Determine outcome (death) | Date and cause of death |
Abbreviations: ICD‐10, International Classification of Disease, 10th edition; NHS, National Health Service; PSA, prostate‐specific antigen; SACT, systemic anti‐cancer therapy.
a
CEPAS is a comprehensive source of data of all SACT prescriptions within the NHS in the West of Scotland (WoS). The numbers of patients receiving SACT within private healthcare are not known but are presumed to be very small due to the nature of the NHS (universal access, with services free at the point of delivery).
b
SMR06 captures information such as TNM staging at initial diagnosis only.
c
PIS does not contain information about medicines dispensed/administered in secondary care.