Analysis of four studies in a comparative framework reveals: health linkage consent rates on British cohort studies higher than on UK household panel surveys.

Gundi Knies,Jonathan Burton

doi:10.1186/1471-2288-14-125

Abstract

BackgroundA number of cohort studies and longitudinal household panel studies in Great Britain have asked for consent to link survey data to administrative health data. We explore commonalities and differences in the process of collecting consent, achieved consent rates and biases in consent with respect to socio-demographic, socio-economic and health characteristics. We hypothesise that British cohort studies which are rooted within the health sciences achieve higher consent rates than the UK household longitudinal studies which are rooted within the social sciences. By contrast, the lack of a specific health focus in household panel studies means there may be less selectivity in consent, in particular, with respect to health characteristics.MethodsSurvey designs and protocols for collecting informed consent to health record linkage on two British cohort studies and two UK household panel studies are systematically compared. Multivariate statistical analysis is then performed on information from one cohort and two household panel studies that share a great deal of the data linkage protocol but vary according to study branding, survey design and study population.ResultsWe find that consent is higher in the British cohort studies than in the UK household panel studies, and is higher the more health-focused the study is. There are no systematic patterns of consent bias across the studies and where effects exist within a study or study type they tend to be small. Minority ethnic groups will be underrepresented in record linkage studies on the basis of all three studies.ConclusionsSystematic analysis of three studies in a comparative framework suggests that the factors associated with consent are idiosyncratic to the study. Analysis of linked health data is needed to establish whether selectivity in consent means the resulting research databases suffer from any biases that ought to be considered.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2288-14-125) contains supplementary material, which is available to authorized users.

Highlights

A number of cohort studies and longitudinal household panel studies in Great Britain have asked for consent to link survey data to administrative health data
The first hypothesis is that consent rates to link to health records may be lower in studies that do not have a health focus because the request to participate in a health record linkage study may appear less salient
The second hypothesis is that a study with a specific medical and development focus is more likely to suffer from selection bias into a health record linkage study, leading to increased consent bias in the linked dataset

Summary

Methods

We will briefly introduce the cohort and household panel studies analysed in the research. That consent form did not make any specific references to linkage to administrative health records (materials available from the NSHD study team on request). The protocol for asking informed consent to link to health records was as followsd: Sample members were sent a general advance letter informing them about the sweep of data collection. The study information leaflet (available from the authors on request) mentioned that the interviewer will be asking for the cohort member’s and their partner’s consent to add to the responses provided in the study additional information from routine administrative records held by the National Health Service (NHS). The information leaflet about linking administrative records is very similar to the NCDS and BHPS form It did not, include references to GP records and it was not sent with the advance letter. Cross-section of resident population in 2009/10, additional ethnic minority boost

Results

Conclusions

Background

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Discussion

Conclusion