#671 Perinatal factors, age of onset, early glycaemic control, sex and the development of microvascular complications in type 1 diabetes after 30 years
Authors: Hornbrinck Edvin , Lundqvist Martin , Eriksson Jan W , Svensson Maria K 
Published: May 2024

Abstract

Background and Aims
Long-term glycaemic control and duration of disease are both well-established risk factors for the development of complications in type 1 diabetes (T1D). The effect of perinatal factors, age at onset of T1D and early glycaemic control on development of diabetic complications have not been fully evaluated. The aim of this study was to investigate the long-term impact of such factors in childhood-onset type 1 diabetes.

Method
90 subjects diagnosed with T1D between the ages of 0-14 years were included in this prospective observational cohort study in in a geographically defined area in northern Sweden. Baseline data for these subjects have previously been reported by Svensson M et al (Diabetes Care 2004). Outcome and follow-up data was obtained during approximately 30 years of follow-up from the Swedish National Diabetes Registry (NDR). Differences between groups were assessed using independent t-test and Chi-square test. Kaplan-Meier survival curves were used to illustrate time-to-diabetic nephropathy (DN) by sex and age at onset. Multivariable logistic regression analyses were performed to evaluate the influence of risk factors of interest on the development of DN, assessed as any degree of albuminuria without signs of other underlying conditions.

Results
Forty-one subjects (46%) developed any degree of DN during the follow-up period of mean 33 (range 19-40) years after T1D onset. Moreover, 80 subjects (89%) had any degree of retinopathy (RP) and among those, 18 (20%) had proliferative diabetic retinopathy (PDR), and 13 (4%) had both PDR and DN. Mean HbA1c during the first five and ten years after diagnosis was higher in subjects who developed DN or PDR compared to those who did not develop these complications; DN 58 ± 16 vs 51 ± 13 (p = 0.038) and 63 ± 16 vs 55 ± 11 mmol/mol (p = 0.007), respectively; PDR 60 ± 13 vs 53 ± 15 (p = 0.059) and 67 ± 10 vs 56 ± 14 mmol/mol (p = 0.002), respectively. Women had an increased risk of PDR compared to men (28% vs 11%, p = 0.045) and a near-significantly higher risk of DN (55% vs 36%, p = 0.087) (Table 1). Time to DN by sex and by age at onset are shown in Figure 1A and B. Women seemed to have a somewhat lower risk in the early years, but in the later years the risk was increased. A young age at onset of diabetes prolonged the time to development of DN but after twenty years of diabetes duration, no difference was seen. In a multivariate regression analysis, older age of gestation was negatively associated with (OR 95% CI 0.894-0.989, p = 0.017) and hyperglycaemia (higher HbA1c) during the first five years (OR 95% CI 1.004-1.078, p = 0.028) were positively and independently associated with development of DN (Fig. 1C).

Conclusion
Interestingly, longer gestational time at birth and, more well-known, poor early glycaemic control were associated with development of DN after 30 years of diabetes duration. However, there was no impact of age of onset or sex on the long-term risk for DN.