About the DISRA Study

The DISRA study (Diabetes In Stroke Registry Analysis) is a Swedish registry-based study in which researchers from five Swedish universities investigate the relationship between diabetes and stroke from multiple perspectives, using the unique Swedish population-based quality registers.

Aims of the DISRA Study

The overall aim of the DISRA study is to investigate:

• Whether individuals with diabetes have an increased risk of stroke and are more likely to experience disability or death following a stroke compared with individuals without diabetes.
• Whether the effect of treatment with thrombolysis and thrombectomy, respectively, is the same in stroke patients with diabetes as in those without diabetes.
• Whether modern diabetes medications influence the risk of stroke and the effectiveness of thrombolysis and thrombectomy in individuals with type 2 diabetes treated with these medications.

What makes this study unique is that these questions will be addressed by linking two national Swedish registers that have never previously been analysed together: the Swedish Stroke Register (Riksstroke) and the National Diabetes Register.

These registers include the vast majority of Swedish patients diagnosed with stroke and diabetes, respectively. We will analyse data entered between 2005 and 2023, enabling us to describe how the risk of stroke, stroke-related complications, and recovery after stroke have evolved in Sweden during this period. We will also perform analyses comparing the risk of first-ever stroke among individuals with diabetes with that of randomly selected individuals without diabetes from the Swedish Population Register maintained by Statistics Sweden. In addition, we will analyse the risk of recurrent stroke in individuals with and without diabetes.

Thrombectomy Substudy 

In a substudy, we will use the EVAS registry, which includes patients with ischemic stroke who have received acute treatment with thrombectomy. EVAS will be used to analyse whether there are differences in the effectiveness of thrombectomy treatment between individuals with and without diabetes.

The Prescribed Drug Register

To analyse potential effects of modern diabetes medications on the risk of stroke, post-stroke complications, or impaired recovery after stroke, we will use data from the Swedish Prescribed Drug Register to identify individuals with diabetes treated with these medications.

Health Economic Analysis

Finally, we will conduct health economic analyses to determine whether the impact of a stroke event on health-related quality of life and economic costs differs between patients with and without diabetes, as well as how potential changes in stroke incidence among individuals with diabetes affect the overall economic burden of stroke in Sweden.

Why Is the DISRA Study Needed?

Stroke is a collective term for conditions caused by disturbances in cerebral blood supply, resulting in neurological symptoms. The most common type of stroke is caused by a blood clot that obstructs blood flow and leads to oxygen deprivation. If blood flow is not restored, permanent damage occurs in the form of a cerebral infarction. Stroke also includes, to a lesser extent, intracerebral haemorrhage. Spontaneous bleeding into the brain tissue is primarily caused by changes and damage to the brain’s smallest blood vessels and is strongly associated with hypertension.

It is well established that diabetes increases the risk of cardiovascular diseases such as stroke. It is also known that diabetes worsens prognosis in individuals who experience a stroke. Type 2 diabetes, is increasing in prevalence in Sweden and the Western world, while the incidence of stroke and other cardiovascular events is declining.

Given this context, and considering that most studies demonstrating the association between diabetes and stroke were conducted many years ago, there is a strong need for renewed analyses to understand how this relationship appears today.

One factor that may have altered this association is the introduction of newer diabetes treatments, which have been available in Sweden for less than a decade. Of particular interest are two classes of medications for type 2 diabetes: sodium–glucose co-transporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists. These drug classes have been shown to provide cardiovascular protection beyond their glucose-lowering effects, which form the basis of diabetes treatment.

Treatment Options

In the event of an acute ischemic stroke, there are two main treatment options in the acute setting: thrombolysis and thrombectomy. Thrombolysis involves the administration of a clot-dissolving intravenous medication, while thrombectomy entails the mechanical removal of the clot using a catheter inserted into the blood vessel via the groin or wrist. Thrombolysis is performed at most hospitals across the country, whereas thrombectomy is carried out at neurointerventional centres with the necessary expertise for this complex procedure.

While the effect of thrombolysis in patients with diabetes has been studied previously, the effectiveness of thrombectomy in individuals with diabetes has not been evaluated in studies specifically designed for this purpose.

Thus, it remains unclear whether individuals with diabetes derive the same benefit from thrombectomy and whether they experience more frequent or different complications from the procedure compared with individuals without diabetes.

Participating Universities and Scientists

Karolinska Institutet - KI Danderyd Hospital (KI DS) Dr Louise Ziegler (PI), Dr Annika Lundström, PhD student Hedwig Widestedt 

Karolinska Institutet - KI Södersjukhuset (KI SÖS) Professor Thomas Nyström, Associate professor Cesare Patrone, Dr Yuanhang Yang, PhD student Linda Forsell, PhD student Sanna Hagelberg Eng 

Lund University Professor Jesper Petersson, Associate professor Teresa Ullberg, Professor Bo Norrving, PhD student Julia Skogänger

Gothenburg University - Sahlgrenska Academy Associate professor Katarina Eeg Olofsson, Professor Soffia Gudbjörnsdottir

Umeå University Professor Per Wester (also affiliated to KI DS) 

Linköping University Dr Nicklas Ennab Vogel (PhD in health economy)