South Asians with type 2 diabetes are at a higher risk for earlier development of cardiovascular complications than Europeans

Research conducted by the Leiden University Medical Center (LUMC) in cooperation with Haaglanden Medical Center shows that South Asians are in disadvantage irrespective of the presence of diabetic retinopathy. Their findings have been published in Endocrinology, Diabetes & Metabolism.

Diabetic retinopathy (DR) is a complication of diabetes that damages the back of the eye (retina), causing blindness if left undiagnosed and untreated. It has been recently suggested that DR is a predictor for the development of cardiovascular disease. For people from South Asian descent, not only is the prevalence of diabetes and cardiovascular disease higher, but they are also at an increased risk of developing severe DR compared to white Europeans. However, how big this risk gap is between ethnic groups and the relation with DR severity have not been studied.

The HinDu The Hague Diabetes Study

Researchers from the Public Health department of the LUMC/LUMC Campus the Hague in cooperation with the Haaglanden Medical Center have quantified the time difference from the moment of diabetes diagnosis up to a first Major Adverse Cardiovascular Event (MACE) in distinct DR groups (no, mild/moderate only and severe) in South Asians and Europeans. The association between the presence, absence and severity of DR was investigated in 3831 participants of The HinDu The Hague Study. Participants comprised of 1358 South Asian and 2473 white European adults with type 2 diabetes. Patients were treated at the Diabetes Center between 2006 and 2017, with an average follow-up period of 17 years after diabetes diagnosis.

Patients were selected from a diabetes-specific database (DiabetesNed). Descriptive statistic methods were used to analyze patient information and Cox proportional-hazards models – a statistical model commonly used in medical research for investigating the association between the survival time of patients and one or more predictor variables – were used to examine the differences between South Asians and Europeans in terms of MACE within the three RD subgroups.

Comparing DR severity in ethnic groups

Diabetes duration was the same in all DR-subgroups. The percentage of patients without DR was significantly higher in white Europeans and severe DR was twice as high in South Asians. In the absence of DR, no differences were observed in the presence of MACE among both ethnic groups. However, the time until a first MACE was 4 years earlier for South Asians. The prevalence of MACE increased in both ethnic groups with increasing severity of DR, but was significantly higher in South Asians. Our findings indicate that in the presence of DR, MACE difference between the ethnic groups increased from 4 to 7.4 years.

Cardiovascular risk management for South Asians

Presence of DR should be considered an important predictor for the development of cardiovascular disease. However, the current study showed that its absence does not reduce the high cardiovascular risk found particularly in South Asian subgroups. Researchers of The HinDu The Hague Study suggest cardiovascular risk management for South Asians demands, therefore, an early aggressive approach of all cardiovascular risk factors to narrow the time gap until first MACE compared to that of white Europeans.

Read The HinDu The Hague Study findings published in  Endocrinology, Diabetes & Metabolism.