Correctness and Completeness of Breast Cancer Diagnoses Recorded in UK CPRD Aurum and CPRD GOLD Databases: Comparison to Hospital Episode Statistics and Cancer Registry (Companion Paper 2)

Presence of Breast Cancer Information Recorded in United Kingdom Primary Care Databases: Comparison of CPRD Aurum and CPRD GOLD (Companion Paper 1)

Purpose

To evaluate the presence of data elements related to diagnosis and treatment of malignant breast cancer in CPRD Aurum compared to those in the previously validated CPRD GOLD.

Methods

Females in CPRD Aurum or GOLD with a first-time code for malignant breast cancer, mastectomy, or ≥1 prescription for tamoxifen or aromatase inhibitors (2004-2019) were selected. We compared the presence of the codes for breast cancer diagnosis, surgeries (mastectomy, lumpectomy), tamoxifen and aromatase inhibitor prescriptions, radiation, chemotherapy, and supporting clinical codes (suspected breast cancer, lump symptoms, biopsy, lumpectomy, cancer care, referral/visit to specialist, palliative care). Age standardized incidence rates of breast cancer diagnosis in CPRD Aurum and GOLD were calculated.

Results

There were 131,936 eligible patients in CPRD Aurum and 69,102 patients in GOLD. A similar proportion of patients in CPRD Aurum and GOLD had codes for breast cancer diagnosis, mastectomy, drug prescriptions, lump, biopsy, lumpectomy, chemotherapy, and cancer and palliative care coded in their electronic record during follow-up. However, suspected breast cancer, radiation, and referral/visits to specialists were coded more frequently in patients in CPRD Aurum compared to GOLD. Age-standardized incidence rates were similar for CPRD Aurum and GOLD.

Conclusion

Overall, there was consistency between data elements related to malignant breast cancer recorded in CPRD Aurum and GOLD, particularly for the most informative clinical details. These findings provide reassurance that breast cancer information recorded in CPRD Aurum is generally comparable to that recorded in the previously validated CPRD GOLD and support the use of CPRD Aurum for breast cancer research.

Use of the CPRD Aurum Database: Insights Gained from New Data Quality Assessments

Ongoing evaluation of any electronic health data source is critical to assess suitability for its use in medical research. In addition, familiarity with a data source's history and recording practices is important for making informed data source selection, study design choices, and interpretation of results. In this commentary, the authors discuss three studies that assessed different aspects of the quality and completeness of information contained in Clinical Practice Research Datalink (CPRD) Aurum compared to the well-established CPRD GOLD and to other linked data sources, with the aim to describe insights gained through these data quality assessments. Our findings support the view that CPRD Aurum and GOLD are both valuable tools for studies based on information recorded in primary care but should not be used without critical consideration of strengths and limitations. Further, use of linked data should be considered for some studies, after taking into account all relevant factors.