Approach to record linkage of primary care data from Clinical Practice Research Datalink to other health-related patient data: overview and implications

Methods to refine and extend a Pregnancy Register in the UK Clinical Practice Research Datalink primary care databases

PURPOSE

Real-world data represents a valuable tool for pregnancy research. However, an algorithmic approach is needed to ascertain pregnancy timings from this complex data. The Clinical Practice Research Datalink (CPRD) GOLD Pregnancy Register, based on UK Primary care data, has therefore proven to be a valuable research tool. The same algorithmic approach was applied to the CPRD Aurum data to generate an equivalent register in the larger database.

METHODS

Records of female patients registered with a CPRD Aurum contributing practice between the 1st of January 1987 and the 30th of April 2021 were searched for evidence of pregnancy. The algorithm used to generate the CPRD GOLD Pregnancy Register was redeveloped and applied first to CPRD GOLD and then to CPRD Aurum. The resulting CPRD Aurum Pregnancy Register was validated against the CPRD GOLD register, linked Hospital Episode Statistics (HES) and the Office of National Statistics (ONS) live birth data.

RESULTS

There are 16 833 427 pregnancy episodes in the CPRD Aurum Pregnancy Register from 6 724 615 women, more than double the number in CPRD GOLD. The distribution of pregnancy outcome types was comparable between the registers. Across the whole register, there was good concordance between pregnancy episodes found in CPRD Aurum and linked HES. However, both CPRD registers saw a declining number of pregnancy episodes from 2007 onwards, steeper than in HES or the ONS birth data.

CONCLUSIONS

A pregnancy register has been created in CPRD Aurum. Changes in antenatal care policies in the UK have led to declining numbers of pregnancies in EHR primary care data. However, the creation of this pregnancy register has tripled the number of patients in the CPRD Pregnancy Registers and will increase the capacity to study pregnancy in CPRD data, particularly rare or emerging exposures, and outcomes.

Does coprescribing nonsteroidal anti-inflammatory drugs and oral anticoagulants increase the risk of major bleeding, stroke and systemic embolism?

AIMS

To examine the risk of gastrointestinal (GI) bleeding, major bleeding, stroke and systemic embolism associated with prescribing nonsteroidal anti-inflammatory drugs (NSAIDs) to adults receiving oral anticoagulant (OAC) therapy.

METHODS

We conducted a population-based cohort study in adults receiving OAC therapy using linked primary care (Clinical Practice Research Datalink GOLD) and hospital (Hospital Episodes Statistics) electronic health records. We used cause-specific Cox regression models with time-dependent NSAID treatment in a propensity score matched population to estimate the increased risk of GI bleeding, stroke, major bleeding and systemic embolism associated with NSAID use.

RESULTS

The matched cohort contained 3177 patients with OAC therapy alone and 3177 with at least 1 concomitant NSAID prescription. Compared with OAC therapy alone, concomitant prescription of NSAIDs with OACs was associated with increased risk of GI bleeding (hazard ratio [HR] 3.01, 95% confidence interval [CI] 1.63 to 5.55), stroke (HR 2.71, 95% CI 1.48 to 4.96) and major bleeding (HR 2.77, 95% CI 1.84 to 4.19). The association with systemic embolism did not reach statistical significance (HR 3.02, 95% CI 0.82 to 11.07). Sensitivity analyses indicated that the results were robust to changes in exclusion criteria and the choice of potential confounding variables.

CONCLUSION

When OACs are coprescribed with NSAIDs, the risk of adverse bleeding events increases and, simultaneously, the protective effect of OACs to prevent strokes reduces. There is a need for interventions that reduce hazardous prescribing of NSAIDs in people receiving OAC therapy.

Cardiovascular risk profiles: A cross-sectional study evaluating the generalizability of the glucagon-like peptide-1 receptor agonist cardiovascular outcome trials REWIND, LEADER and SUSTAIN-6 to the real-world type 2 diabetes population in the United Kingdom

AIMS

To determine the proportion of UK patients with type 2 diabetes (T2D) who meet the cardiovascular (CV) or combined CV/core eligibility criteria used for the CV outcome trials (CVOTs) of UK-marketed glucagon-like peptide-1 receptor agonists (GLP-1RAs) showing CV benefit (dulaglutide in REWIND, liraglutide in LEADER and injectable semaglutide in SUSTAIN-6).

MATERIALS AND METHODS

Adults with T2D on/before June 2018 were identified from the UK Clinical Practice Research Datalink GOLD primary care database and linked to Hospital Episode Statistics data (Protocol 19_262). Patient CV and clinical data were evaluated against the CVOT eligibility criteria. Data were analysed descriptively.

RESULTS

The study cohort (N = 33 118 patients with T2D) had a mean (standard deviation) age of 66.0 (13.3) years and 56.6% were male. Almost two-thirds (64.5%) of the study cohort met the CV criteria for REWIND, versus 43.0% for both LEADER and SUSTAIN-6. The proportions of the study cohort who met the CVOT criteria of "established CV disease" and "CV risk factors only" for REWIND were 22.4% and 42.1%, respectively, versus 38.7% and 4.3%, respectively, for both LEADER and SUSTAIN-6. The proportions of patients satisfying both CV and core criteria were 44.4% for REWIND, 13.3% for LEADER and 13.5% for SUSTAIN-6. Study findings remained consistent when restricted to GLP-1RA users.

CONCLUSIONS

REWIND captured a trial population more representative of the real-world T2D population in the United Kingdom than LEADER or SUSTAIN-6 with regard to both CV and combined CV/core eligibility criteria.