Concordance in the recording of stroke across UK primary and secondary care datasets: a population-based cohort study.

Ann Morgan,Caroline Minassian,Jennifer Quint,Liam Smeeth,Sarah-Jo Sinnott

doi:10.3399/bjgpo.2020.0117

Abstract

BackgroundPrevious work has demonstrated that the recording of acute health outcomes, such as myocardial infarction (MI), may be suboptimal in primary healthcare databases.AimTo assess the completeness and accuracy of the recording of stroke in UK primary care.Design & settingA population-based longitudinal cohort study.MethodCases of stroke were identified separately in Clinical Practice Research Datalink (CPRD) primary care records and linked Hospital Episode Statistics (HES). The recording of events in the same patient across the two datasets was compared. The reliability of strategies to identify fatal strokes in primary care and hospital records was also assessed.ResultsOf the 75 674 stroke events that were identified in either CPRD or HES data during the period of the study, 54 929 (72.6%) were recorded in CPRD and 51 013 (67.4%) were recorded in HES. Two-fifths (n = 30 268) of all recorded strokes were found in both datasets (allowing for a time window of 120 days). Among these 'matched' strokes the subtype was recorded accurately in approximately 75% of CPRD records (compared with coding in HES); however, 43.5% of ischaemic strokes in HES were coded as 'non-specific' strokes in CPRD data. Furthermore, 48.2% had same-day recordings, and 56.2% were date-matched within ±1 day.ConclusionThe completeness and accuracy of stroke recording is improved by the use of linked hospital and primary care records. For studies that have a time-sensitive research question, the use of linked, as opposed to stand-alone, CPRD data is strongly recommended.

Highlights

Stroke is the UK’s fourth most common cause of death[1] and a major cause of disability.[2]
The completeness and accuracy of stroke recording is improved by the use of linked hospital and primary care records
This study demonstrates that reliance on a single dataset to identify stroke is likely to underestimate cases of stroke, and, for this reason, the use of linked health data is advocated, especially for research in which the timing of stroke is critical

Summary

Introduction

Stroke is the UK’s fourth most common cause of death[1] and a major cause of disability.[2]. Routinely-collected data, including electronic health records (EHRs) from primary care and administrative data from hospitals, are frequently used to study stroke.[4,5] such data are becoming increasingly important for regulatory decision making concerning the effectiveness and cardiovascular safety of drugs, especially since traditional clinical trials are expensive, limited in their generalisability, and require long follow-u p times to accrue major events such as stroke.[6,7] Other uses of EHR data extend to clinical risk prediction[8,9] and interventional research such as pragmatic trials.[10] The validity of any research based on real-w orld data is, dependent on how well researchers can identify outcomes such as stroke. Several studies have revealed discrepancies between data sources in the recording of certain health outcomes, in particular acute outcomes, and have noted that reliance on just one data source risks missing a substantial proportion of cases.[11,12]. Previous work has demonstrated that the recording of acute health outcomes, such as myocardial infarction (MI), may be suboptimal in primary healthcare databases

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