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Baden-Württemberg: Significantly Reduced Risk of Going Blind among People with and without Diabetes

So far, Germany has lacked reliable figures for the comparison of blindness incidence in people with and without diabetes as well as a time-trend analysis of the incidence rates. Researchers at the DZD partner German Diabetes Center (DDZ) have now calculated that the risk of blindness in the population in southern Germany has decreased significantly – in people with diabetes more than in people without diabetes. The results of the analysis suggest that in addition to the treatment of diabetic retinopathy, the early detection and treatment of cataracts and glaucoma as well as age-related macular degeneration have also improved.

Neuerblindungsrate bei Personen mit Diabetes (gestrichelte Linie) und ohne Diabetes (durchgezogene Linie) zwischen 1990 und 2012. Quelle: DDZ

Almost nine percent of the world's population (approx. 415 million) suffer from diabetes. This is a common cause of blindness. As a result, early in the 1990s measures were taken to reduce the blindness incidence in people with diabetes. For example, guidelines were introduced in Germany that recommended regular examinations of the ocular fundus in order to detect and treat diabetic retinopathy at an early stage. The scientists at the German Diabetes Center (DDZ) have therefore investigated new-onset blindness in people with and without diabetes in Baden-Württemberg in cooperation with the State Health Office and the local welfare authorities in Baden-Württemberg. The study was published in the journal Diabetes Care.

Database and Results
The database for the study comprised newly recognized recipients of disability benefits for the blind in about 50 percent of all districts and district-free cities in Baden-Württemberg, which were recorded for the period 2008-2012. A total of 1,897 people were newly registered as recipients of disability benefits due to blindness (23.7% of them with diabetes). Between 2008 and 2012, the number of people newly registered as disability benefit recipients due to blindness declined in the diabetic population group. Out of 100,000 people with diabetes, there were around 17 new cases of blindness in 2008, compared with only around 9 in 2012. Likewise, for the first time, a decrease was also observed in the number of persons without diabetes who were  newly registered as recipients of benefits for the blind. Of the 100,000 persons without diabetes, there were around 9 new cases in 2008. In 2012, seven new cases were registered. There were no gender differences – similar results were reported for men and women. The relative risk, which indicates how much higher the risk of blindness in the population with diabetes is compared to the population without diabetes, decreased from factor 2 in 2008 to factor 1.4 in 2012. "The reduction was thus much more pronounced in persons with diabetes – especially in the last decade,” said Professor Andrea Icks, MD, director of the Institute for Health Services Research and Health Economics at the DDZ.

Conclusion
In summary, it can be concluded that the incidence risk of blindness in Baden-Württemberg has decreased significantly both for people with and without diabetes. The observed decline is independent of the aging population. Therefore, the authors of the study suggest that the continuous decline in blindness is due to the improvement in diabetic retinopathy care, as well as the earlier identification and treatment of other eye diseases such as cataracts, glaucoma and senile macular degeneration.

A comparison with study results from other countries is difficult because the definitions and detection of blindness differ significantly. In Germany, the definition of blindness – vision less than a fiftieth of normal vision – is very strict. In order to gain insight into whether similar results are also observed in other regions in Germany for a longer or more recent period, a corresponding analysis of data from Saxony for the period 2008-2016 is currently being undertaken.

    • Nearly 50 percent reduction in the incidence rate of blindness in the diabetic population in Baden-Württemberg between 2008 and 2012
    • The incidence rate of blindness among people without diabetes decreased by almost 30 percent during this period
    • Continuous decline probably due to improved early detection and treatment of eye diseases and diabetic retinopathy care

    Original publication:
    Claessen H, Kvitkina T, Narres M, Trautner C, Zöllner I, Icks A. Decreasing incidence of blindness in people with and without diabetes in southern Germany, 2008–2012. Diabetes Care 41(3):478-484. doi: 10.2337/dc17-2031. Epub 2018 Jan 9.