Type 2 diabetes is one of the greatest causes of disability, death and treatment costs in the UK. There are currently stark disparities in the management of type 2 diabetes across different ethnic groups resulting in significant health inequalities. Several classes of second-line diabetes medications are available for prescription in UK primary care, but it is currently unknown whether the effectiveness of these treatments differs by ethnicity, as evidence to date has been predominantly derived from white European populations. This study will use electronic health records to look at the comparative effectiveness of classes of type 2 diabetes medications at preventing cardiovascular complications among people from different ethnic groups in the UK. The outputs of this research will contribute to a body of evidence that can inform diabetes guidelines, potentially supporting the introduction of targeted recommendations for people from different ethnic groups and the practice of more personalized medicine approaches, with the aim of reducing the burden of diabetes complications in the UK.
This study will be a retrospective cohort study of ethnic differences in the comparative effectiveness of classes of second-line diabetes medications at preventing cardiovascular complications. The first objective is to describe prescription patterns for each class of antidiabetic medication by ethnicity. The second objective will compare the risk of major cardiovascular outcomes, microvascular disease and cardiovascular risk factors associated with each class of antidiabetic medication when used following metformin monotherapy among patients with type 2 diabetes. The third objective will determine if the association between the class of antidiabetic medication and major cardiovascular outcomes, microvascular disease and cardiovascular risk factors varies with ethnicity by comparing the estimated treatment effects within and across ethnic groups. For objectives 2 and 3, Cox proportional hazards model will be used to estimate hazard ratios for cardiovascular outcomes for each class of medication.
The study population will be adults (18 years and over) with type 2 diabetes who were prescribed metformin as first-line treatment and were intensified onto second-line treatment between 2004-2014 in the UK. The primary exposure of interest is a prescription of one of classes of antidiabetic medication currently recommended for second-line treatment in the UK, which will be detected in CPRD datasets. The outcomes of interest are cardiovascular events and all-cause mortality, which will be detected in CPRD, HES and ONS datasets.
The outcomes of this research may provide evidence to facilitate clinical decision making for effective and personalised type 2 diabetes treatments. The research also has potential to reduce the high economic burden associated with diabetes complications by ensuring that people are on the most effective treatment from an early stage in their disease. The study may also contribute to our understanding of sources of ethnic inequalities in diabetes outcomes.
Primary outcome:
• Major cardiovascular outcomes (myocardial infarction, ischaemic stroke, and cardiovascular death)
• Microvascular disease (chronic kidney disease, diabetic retinopathy, diabetic neuropathy)
Secondary outcomes:
• Cardiovascular risk (QRISK2 score)
• Hypertension
• HbA1c levels
Christopher Rentsch - Chief Investigator - London School of Hygiene & Tropical Medicine ( LSHTM )
Mia Harley - Corresponding Applicant - London School of Hygiene & Tropical Medicine ( LSHTM )
Elizabeth Williamson - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Rohini Mathur - Collaborator - Queen Mary University of London
Rohini Mathur - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;Practice Level Index of Multiple Deprivation