Educational inequalities in statin treatment for preventing cardiovascular disease: cross-sectional analysis of UK Biobank
Authors: Carter Alice R , Gill Dipender , Morris Richard , Smith George Davey , Taylor Amy E , Davies Neil M , Howe Laura D 
Published: June 2020

Background

The most socioeconomically deprived individuals remain at the greatest risk of cardiovascular disease. Differences in risk adjusted use of statins between educational groups may contribute to these inequalities. We explore whether people with lower levels of educational attainment are less likely to take statins for a given level of cardiovascular risk.

Methods and findings

Using data from a large prospective cohort study, UK Biobank, we calculated a QRISK3 cardiovascular risk score for 472 097 eligible participants with complete data on self-reported educational attainment and statin use (55% female; mean age, 56). We used logistic regression to explore the association between i) QRISK3 score and self-report statin use and ii) educational attainment and self-report statin use. We then stratified the association of QRISK3 score, and statin use by strata of educational attainment to test for an interaction. In this sample, greater education was associated with lower statin use, whilst higher cardiovascular risk (assessed by QRISK3 score) was associated with higher statin use in both females and males. There was evidence of an interaction between QRISK3 and education, such that for the same QRISK3 score, people with more education were more likely to report taking statins. For example, in women with 7 years of schooling, equivalent to leaving school with no formal qualifications, a one unit increase in QRISK3 score was associated with a 7% higher odds of statin use (odds ratio (OR) 1.07, 95% CI 1.07, 1.07). In contrast, in women with 20 years of schooling, equivalent to obtaining a degree, a one unit increase in QRISK3 score was associated with an 14% higher odds of statin use (OR 1.14, 95% CI 1.14, 1.15). Comparable ORs in men were 1.04 (95% CI 1.04, 1.05) for men with 7 years of schooling and (95% CI 1.08, 1.08) for men with 20 years of schooling. Linkage between UK biobank and primary care data meant we were able to carry out a number of sensitivity analyses to test the robustness of our findings. However, a limitation of our study is that a number of assumptions were made when deriving QRISK3 scores which may overestimate the scores.

Conclusions

For the same level of cardiovascular risk, individuals with lower educational attainment are less likely to receive statins, likely contributing to health inequalities.

What is already known on this topic?

Despite reductions in the rates of cardiovascular disease in high income countries, individuals who are the most socioeconomically deprived remain at the highest risk.

Although intermediate lifestyle and behavioural risk factors explain some of this, much of the effect remains unexplained.

What does this study add?

For the same increase in QRISK3 score, the likelihood of statin use increased more in individuals with high educational attainment compared with individuals with lower educational attainment.

These results were similar when using UK Biobank to derive QRISK3 scores and when using QRISK scores recorded in primary care records, and when using self-reported statin prescription data or prescription data from linked primary care records.

The mechanisms leading to these differences are unknown, but both health seeking behaviours and clinical factors may contribute.