Large panel-survey data demonstrated country-level and ethnic minority variation in consent for health record linkage

To investigate individual, household, and country variation in consent to health record linkage.

Data from 50,994 individuals aged 16-74 years recruited to wave 1 of a large UK general purpose household survey (January 2009-December 2010) were analyzed using multilevel logistic regression models.

Overall, 70.7% of respondents consented to record linkage. Younger age, marriage, tenure, car ownership, and education were all significantly associated with consent, although there was little deviation from 70% in subgroups defined by these variables. There were small increases in consent rates in individuals with poor health when defined by self-reported long-term limiting illness [adjusted odds ratio (OR) = 1.11; 95% confidence intervals (CIs): 1.06, 1.16], less so when defined by General Health Questionnaire score (adjusted OR = 1.05; 95% CIs: 1.00, 1.10), but the range in absolute consent rates between categories was generally less than 10%. Larger differences were observed for those of nonwhite ethnicity who were 38% less likely to consent (adjusted OR = 0.62; 95% CIs: 0.59, 0.66). Consent was higher in Scotland than England (adjusted OR = 1.17; 95% CIs: 1.06, 1.29) but lower in Northern Ireland (adjusted OR = 0.56; 95% CIs: 0.50, 0.63).

The modest overall level of systematic bias in consent to record linkage provides reassurance for record linkage potential in general purpose household surveys. However, the low consent rates among nonwhite ethnic minority survey respondents will further compound their low survey participation rates. The reason for the country-level variation requires further study.