Comparison of characteristics of patients with lung cancer in UK 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.