Background and aim: Both micro- and macro vascular complications represent major problems for diabetes patients and monitoring of the extent of these among diabetes patients is essential. Several studies have reported decreasing complications rates. We describe the burden and trend in 18 groups of complications in persons with diabetes in Denmark 1996-2016.

Methods: We compiled a diabetes register for the entire Danish population, including reliable classification of type of diabetes. From the National Patient Register we extracted dates of recorded complications in 18 classes. Binomial regression was used to describe the prevalence of complications at diagnosis and change in these over time. Rate models based on Poisson likelihood were used to describe the incidence rates and changes in these. Analyses were conducted separately for T1D and T2D, and controlled for sex, age, duration of diabetes and including a linear term to describe the calendar time effect (date of diagnosis).

Results: The prevalence at diagnosis of previous CVD was 10% in T1D and 37% in T2D, with annual relative changes of 3% in T1D and 5% in T2D. Retinopathy prevalence at diagnosis was 4.3% in T1D and 1.7% in T2D with no change in T1D, but a relative decrease of 6% in T2D. We found similar decreases in rates of complications in T1D and T2D; decrease of 2%/year in rates of CVD, 5%/year in amputations, while there were no changes in the incidence rates of retinopathy and renal disease over the period 1996-2016. For most complications we found a very high incidence during the first year after diagnosis, most likely reflecting a diagnostic catch-up and not any biological phenomenon.

Conclusions: A steady decrease in incidence rates of most complications was seen, but not for microvascular complications. The pattern of complications at diagnosis was more mixed, influenced by fluctuations in diagnostic activity over the period. In general an encouraging trend in complication occurrence was seen in Denmark in the period 1996-2016.


B. Carstensen: Stock/Shareholder; Self; Novo Nordisk A/S. H. Amadid: None. M.E. Jørgensen: Research Support; Self; Amgen, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Sanofi-Aventis. Stock/Shareholder; Self; Novo Nordisk A/S.

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