In the last decades, the prevalence of diabetes is increasing in virtually all regions of the world. The prevalence in Sweden has been estimated to 4-6%. Type 2 diabetes is associated with macrovascular complications as well as microvascular complications (nephropathy, retinopathy and neuropathy). In Sweden, diabetes is the most common reason for severe chronic kidney disease and need for renal replacement therapy.
In recent years, studies have indicated that variability (fluctuations) in long-term glucose -control (HbA1c), independent of high glucose levels (exposure), may be an additional risk factor for development of macrovascular, as well as microvascular complications, such as nephropathy. Studies targeting the association between variability in long-term glucose control (HbA1c) and microvascular complications, such as diabetic nephropathy, is still an evolving field of knowledge.
Socioeconomic factors like immigrant background, low educational achievement or low-income level have been shown to correlate to an increased risk for type 2 diabetes, in a Swedish population.
Not much is known about the association between socioeconomic factors and long-term glucose variability, a potential risk factor for renal damage. Some studies have shown that individuals with type 2 diabetes, detected in primary care screening, have a lower mortality compared to clinically (symptom) detected individuals. Little is known about the correlation between screening for type 2 diabetes and potential prevention or delay of renal complications.
Study I is a nested-case cohort study to examine the correlation between long-term glucose variability in (HbA1c), defined by coefficient of variation, and decline in renal function (change in eGFR). Our cohort will be the DiabNorr registry that comprises 2501 individuals with a confirmed diagnosis of type 2 diabetes.
Study II will use structural equation modelling to examine the correlation between variability in HbA1c long-term glucose control (HbA1c) and decline of renal function in the presence of a set of baseline and time-varying confounders.
Study III is a retrospective cohort study. In this study we will link data from LISA to the DiabNorr registry, to evaluate the impact of socioeconomic factors such as educational level, unemployment, need for income support or health care support, on variability of long-term glucose control (HbA1c), level of glucose control (exposure) and potential decline in renal function. on variability of HbA1c, glucose control and/or decline in renal function.
Study IV is a retrospective cohort study to examine the trajectory of renal function before and after diagnosis of type 2 diabetes. We will also examine if socioeconomic factors impact the trajectory of renal function after diagnosis. Patients with screening and clinically (symptoms) detected type 2 diabetes will be identified and compared.