These groups seem to have a higher risk of micro-vascular complications due to factors such diagnosis when young, poor metabolic control, co-morbidity and socioeconomic factors. Meanwhile, there is evidence to suggest that some ethnic minorities may be protected from macro-vascular complications.
Rich data available
In Denmark, individually linked, un-biased information is available from existing national registers on diabetes incidence, mortality, metabolic control, co-morbidity, socio-economic status and other confounders such as smoking status and BMI. This provides a unique opportunity, to study the following specific aims:
- To examine the incidence rates and prevalence of diabetes among migrants in Denmark compared to the Danish population.
- To compare standardised mortality rates (SMRs) for individuals with- and without diabetes, according to migration status.
- To compare incidence rates of micro- and macro-vascular diabetes complications for individuals with and without diabetes, and to study whether migration status influences the association
- By applying trajectory of change analysis in patients with repeated measurements of HbA1c, lipids, blood pressure and urinary albumin-creatinine, to analyse differences in the time sequence of metabolic changes prior to complication diagnosis, according to migration status.
- To compare indicators of quality of care (frequency of examinations of HbA1c, blood pressure, lipids, urinary albumin excretion rate, foot- and eye-examinations, and process indicators of anti-diabetic treatment, blood pressure and lipid lowering treatment) according to migration status, and to study the association with risk of complications and mortality.
A number of clinical and administrative registers in Denmark will be linked for clinical and background information on Danish diabetes patients. These include the following:
- The National Diabetes Register (NDR) contains records since 1995 for about 400,000 people with diabetes.
- Migrants living in Denmark will be identified through the Central Population Register as those persons born outside Denmark but presently living in Denmark. Also, we will obtain information about second-generation migrants from the Danish civil registration system register.
- We will collect information on diabetes treatment status and levels of intermediate clinical measures from the Danish Adult Diabetes Database (DVDD).
- Socio-economic information since 1980 (type of employment, income, education and marital status) is available from Statistics Denmark.
- Information about diabetes complications will be based on data from the National Patient Registry.
- Based on NDR, nation-wide prevalence estimates for diabetes will be modelled separately for each year and sex. Incidence rates of diabetes among migrant groups will be modelled by age and calendar time (‘date’) and time since inclusion in the register (‘duration of diabetes’).
- Based on the DVDD, rates will be analysed by Poisson models for the number of counts (complication cases or mortality). Incidence of complications among diabetic patients will be modelled by age, calendar time and diabetes duration.
- Multilevel longitudinal modelling will be used to estimate trajectories of glucose, blood pressure, lipids and urinary albumin-creatinine ratio prior to complication diagnosis.
The results from this study may inform clinicians and health policy makers on the relevance of developing targeted care for the selected migrant population.
We expect to identify subgroups among migrants that may have higher incidence rates, mortality rates and risk of complications and point at potential explanations for such differences.
We expect to be able to identify well-defined subgroups of the population with increased risk of developing diabetes, increased risk of diabetic complications or even increased mortality. We will also be able to point at possible reasons for these differences. Such knowledge may guide us towards groups with special clinical needs that may benefit from targeted treatment. Therefore, this study may inform future clinical care of minority groups in the society.
Funding and collaborators
This project is performed in collaboration with Research Centre for Migration, Ethnicity and Health (MESU) at the University of Copenhagen, and the Health Promotion Research at SDCC.