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.

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)

Purpose

To evaluate the new Clinical Practice Research Datalink (CPRD) Aurum database, we estimated 'correctness' (ie accuracy, validity) and 'completeness' (ie presence, missingness) of malignant breast cancer diagnoses recorded in CPRD Aurum compared to external linked data sources: Hospital Episode Statistics (HES) Admitted Patient Care (APC), HES Outpatient (OP), and Cancer Registry (CR), and to the previously validated CPRD GOLD.

Methods

Linkage-eligible, female patients with incident malignant breast cancer diagnosis recorded in at least one study data source were selected. Correctness was the proportion of malignant breast cancer cases recorded in CPRD Aurum or GOLD who also had a diagnosis recorded in HES APC/OP (2004-2019) or CR (2004-2016). Completeness was estimated by identifying all malignant breast cancer diagnoses in HES APC/OP or CR and calculating the proportion with a concordant diagnosis in CPRD Aurum or GOLD.

Results

Compared to HES APC/OP, there were 85,659 and 31,452 eligible patients in CPRD Aurum and GOLD, respectively. Correctness estimates were high (CPRD Aurum 83.5%, GOLD 81.7%). Compared to CR, there were 70,190 and 29,597 eligible patients in CPRD Aurum and GOLD, respectively: correctness was 89.1% for CPRD Aurum and 88.2% for GOLD. Completeness estimates for CPRD Aurum and GOLD were high (>90%). Diagnoses were recorded in CPRD Aurum within -7 to 74 days of those in the linked sources. Reasons for discordant diagnostic coding included presence of treatment or other clinical codes only, diagnosis coded after end of follow-up, non-malignant breast cancer in linked data, and administrative codes in lieu of diagnostic codes.

Conclusion

These results indicate that correctness and completeness of malignant breast cancer diagnoses in CPRD Aurum were high and similar to CPRD GOLD. This provides confidence in use of CPRD Aurum for research purposes. Where complete case capture is important, researchers should consider linkage to HES APC or CR.

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.

Comparison of Rheumatoid Arthritis Information Recorded in UK CPRD Aurum and CPRD GOLD Databases (Companion Paper 3)

Purpose

To report distribution of codes associated with a rheumatoid arthritis (RA) diagnosis recorded in Clinical Practice Research Datalink (CPRD) Aurum compared to the previously validated CPRD GOLD database as a critical step toward making decisions about CPRD Aurum's suitability for medical research.

Patients and Methods

We analyzed the distribution of codes for RA diagnoses, labs, and treatments in the new CPRD Aurum database, compared to the CPRD GOLD database by selecting relevant indicators of RA diagnosis, treatment, and clinical care. We included all patients in England in CPRD Aurum and CPRD GOLD with an incident diagnosis code for RA on or after 1 January 2005 and at least two years recorded data before first RA diagnosis.

Results

We found 53,083 and 18,167 patients with a new diagnosis code for RA in CPRD Aurum and CPRD GOLD, respectively. In both databases approximately 67% were female with similar mean ages at first diagnosis. There were few differences in RA-related recording patterns between the two data sources. Before first RA diagnosis, CPRD Aurum patients had more RA-specific labs and other supporting clinical codes. After diagnosis, CPRD Aurum patients had more RA diagnoses coded and more often had 10+ general RA labs than patients in CPRD GOLD. More CPRD GOLD patients had 10+ prescriptions for conventional disease-modifying antirheumatic drugs (cDMARD) compared to CPRD Aurum. Otherwise, the distribution of drugs used to treat RA was similar between databases. The standardized incidence of RA was similar between databases.

Conclusion

Overall, among patients with a diagnosis code for RA, recording of diagnoses, prescription drugs, and labs were similar between CPRD Aurum and CPRD GOLD. Slight differences were found for a few variables, but overall, we found consistency between the databases. In addition, standardized incidence of RA was similar between databases.

Comparison of characteristics of patients with lung cancer in U.K. primary care databases: Clinical Practice Research Datalink Aurum and GOLD

INTRODUCTION

In recent years, the number of general practices contributing to the Clinical Practice Research Datalink (CPRD) database GOLD is decreasing. Therefore, for research questions addressing for instance novel treatments requiring up-to-date data, sample size will become an important consideration in study feasibility. In recent years, CPRD Aurum, containing information of practices that use EMIS software, has become an additional data source that is being used for CPRD studies. In order to establish whether Aurum is suited to act as data source for future studies in the field of lung cancer research, we aimed to compare characteristics between patients with lung cancer in Aurum and GOLD.

METHODS

A retrospective study was performed comparing characteristics and overall survival (OS) of patients with lung cancer in Aurum and GOLD. To further evaluate similarity, hypothetical eligibility of these patients in Aurum and GOLD was compared for 11 randomized clinical trials (RCTs).

RESULTS

Baseline characteristics registered in Aurum and GOLD were largely similar, with some clinically irrelevant differences for previous malignancies, deviant laboratory values and drug use. Median OS was 9.8 and 9.0 months for patients in Aurum and GOLD, respectively. Potential RCT eligibility varied between 49.4% and 79.5% and 49.1% and 78.1% for patients in Aurum and GOLD, respectively. Mortality rates and the comparison of the obtained HRs per hypothetical eligibility cohort per RCT were similar in Aurum and GOLD.

CONCLUSION

This study showed that data of patients with lung cancer in Aurum and GOLD are largely comparable, suggesting that Aurum is suitable for future epidemiological lung cancer research.

CPRD GOLD and linked ONS mortality records: Reconciling guidelines

BACKGROUND

The Clinical Practice Research Datalink (CPRD) GOLD is an extremely influential U.K. primary care dataset for epidemiological research having a number of published papers based on its data much bigger than any other U.K. primary care dataset. The Office for National Statistics (ONS) death data for England can be linked to GOLD at the patient level and are considered the gold standard on mortality. GOLD, which also holds death data, has been recently assessed against ONS linked dataset and the accuracy of its dates of death has been deemed sufficient for the majority of observational studies. However, there is a lack of guidance on how to manage the challenges existing when ONS mortality and GOLD datasets are linked, including linkage coverage period, linkage correctness likelihood, linkage regional limitations and data discrepancy.

OBJECTIVES

Provide reconciling guidelines on how to make maximum and at the same time trustworthy use of mortality information coming from both GOLD and ONS linked datasets with the aim of improving the quality, reproducibility, transparency and comparison of clinical research.

METHOD AND RESULTS

We have developed recommendations on how to manage mortality data coming from both GOLD and linked ONS, taking into account linkage coverage period, linkage correctness likelihood, linkage regional limitations and data discrepancies between these two datasets. We have also implemented these guidelines in an SQL algorithm for researchers to use.

CONCLUSION

We have provided detailed guidelines on the reconciliation of mortality data between GOLD and ONS linked death datasets, taking into account both their strengths and limitations. The consistent application of these guidelines made practical by an SQL algorithm, has the potential to improve clinical research quality, reproducibility, transparency and comparison.

Incidence, Prevalence, and Survival of Patients with Idiopathic Pulmonary Fibrosis in the UK

Introduction

Recent developments in the care of patients with idiopathic pulmonary fibrosis have the potential to improve survival rates. Population-based estimates of the current disease burden are needed to evaluate the future impact of newly approved therapies. The objective of this study is to describe incidence, prevalence, and survival of idiopathic pulmonary fibrosis patients in the UK.

Methods

Between 2000 and 2012, a patient cohort (N = 9,748,108), identified from Clinical Practice Research Datalink primary care data, was used to identify incident and prevalent cases of idiopathic pulmonary fibrosis–clinical syndrome. Incident cases were followed up to identify deaths. Poisson and Cox regressions were used to calculate incidence rate ratios (IRR) and hazard ratios for mortality, respectively. Adjustments were made for age, gender, and strategic health authority. Survival from diagnosis was estimated using Kaplan–Meier analysis.

Results

In total 1491 and 4527 incident cases were identified using narrow and broad idiopathic pulmonary fibrosis–clinical syndrome definitions, respectively. Incidence and prevalence increased during the study. Compared with 2000, a near 80% increase in incidence was observed by 2012 [IRR 1.78 (95% CI 1.50–2.11; broad definition)], despite an observed decrease using the narrow definition [0.50 (0.38–0.65)]. Median survival was 3.0 years (95% CI 2.8–3.1) and 2.7 years (95% CI 2.5–3.0) in broad (n = 2168) and narrow case sets (n = 996), respectively. No significant changes in survival were observed.

Conclusions

Idiopathic pulmonary fibrosis incidence rates have increased since 2000 and survival remains poor. These results provide a benchmark against which the effects of future treatment changes can be measured.

Funding

InterMune UK and Ireland (now part of F. Hoffman La Roche).

Electronic supplementary material

The online version of this article (10.1007/s12325-018-0693-1) contains supplementary material, which is available to authorized users.