HbA(1c) level as a risk factor for retinopathy and nephropathy in children and adults with type 1 diabetes: Swedish population based cohort study.

To evaluate if the lowest target level for glycated haemoglobin (HbA1c) of <6.5% is associated with lower risk for retinopathy and nephropathy than less tight control in children and adults with type 1 diabetes. Population based cohort study. Swedish National Diabetes Registry, 1 January 1998 to 31 December 2017. 10 398 children and adults with type 1 diabetes followed from diagnosis, or close thereafter, until end of 2017. Relative risk (odds ratios) for retinopathy and nephropathy for different mean levels of HbA1c. Mean age of participants was 14.7 years (43.4% female), mean duration of diabetes was 1.3 years, and mean HbA1c level was 8.0% (63.4 mmol/mol). After adjustment for age, sex, duration of diabetes, blood pressure, blood lipid levels, body mass index, and smoking, the odds ratio for mean HbA1c <6.5% (<48 mmol/mol) compared with 6.5-6.9% (48-52 mmol/mol) for any retinopathy (simplex or worse) was 0.77 (95% confidence interval 0.56 to 1.05, P=0.10), for preproliferative diabetic retinopathy or worse was 3.29 (0.99 to 10.96, P=0.05), for proliferative diabetic retinopathy was 2.48 (0.71 to 8.62, P=0.15), for microalbuminuria or worse was 0.98 (0.60 to 1.61, P=0.95), and for macroalbuminuria was 2.47 (0.69 to 8.87, P=0.17). Compared with HbA1c levels 6.5-6.9%, HbA1c levels 7.0-7.4% (53-57 mmol/mol) were associated with an increased risk of any retinopathy (1.31, 1.05 to 1.64, P=0.02) and microalbuminuria (1.55, 1.03 to 2.32, P=0.03). The risk for proliferative retinopathy (5.98, 2.10 to 17.06, P<0.001) and macroalbuminuria (3.43, 1.14 to 10.26, P=0.03) increased at HbA1c levels >8.6% (>70 mmol/mol). The risk for severe hypoglycaemia was increased at mean HbA1c <6.5% compared with 6.5-6.9% (relative risk 1.34, 95% confidence interval 1.09 to 1.64, P=0.005). Risk of retinopathy and nephropathy did not differ at HbA1c levels <6.5% but increased for severe hypoglycaemia compared with HbA1c levels 6.5-6.9%. The risk for severe complications mainly occurred at HbA1c levels >8.6%, but for milder complications was increased at HbA1c levels >7.0%.

Lind M ，Pivodic A ，Svensson AM ，Ólafsdóttir AF ，Wedel H ，Ludvigsson J ... -  《BMJ-British Medical Journal》

Impact of HbA1c, followed from onset of type 1 diabetes, on the development of severe retinopathy and nephropathy: the VISS Study (Vascular Diabetic Complications in Southeast Sweden).

HbA1c is strongly related to the development of diabetes complications, but it is still controversial which HbA1c level to strive for in the treatment of type 1 diabetes. The aim of the current study was to evaluate HbA1c, followed from diagnosis, as a predictor of severe microvascular complications and to formulate HbA1c target levels for treatment. A longitudinal observation study followed an unselected population of 451 patients diagnosed with type 1 diabetes during 1983-1987 before the age of 35 years in a region of Southeast Sweden. Retinopathy was evaluated by fundus photography and nephropathy data collected from medical records. HbA1c was measured starting from diagnosis and during the whole follow-up period of 20-24 years. Long-term weighted mean HbA1c was then calculated. Complications were analyzed in relation to HbA1c levels. The incidence of proliferative retinopathy and persistent macroalbuminuria increased sharply and occurred earlier with increasing long-term mean HbA1c. None of the 451 patients developed proliferative retinopathy or persistent macroalbuminuria below long-term weighted mean HbA1c 7.6% (60 mmol/mol); 51% of the patients with long-term mean HbA1c above 9.5% (80 mmol/mol) developed proliferative retinopathy and 23% persistent macroalbuminuria. Long-term weighted mean HbA1c, measured from diagnosis, is closely associated with the development of severe complications in type 1 diabetes. Keeping HbA1c below 7.6% (60 mmol/mol) as a treatment target seems to prevent proliferative retinopathy and persistent macroalbuminuria for up to 20 years.

Nordwall M ，Abrahamsson M ，Dhir M ，Fredrikson M ，Ludvigsson J ，Arnqvist HJ ... -  《-》

The association between retinopathy, nephropathy, cardiovascular disease and long-term metabolic control in type 1 diabetes mellitus: a 5 year follow-up study of 442 adult patients in routine care.

Agardh CD ，Agardh E ，Torffvit O 《DIABETES RESEARCH AND CLINICAL PRACTICE》

A high mean-HbA1c value 3-15 months after diagnosis of type 1 diabetes in childhood is related to metabolic control, macroalbuminuria, and retinopathy in early adulthood--a pilot study using two nation-wide population based quality registries.

Intensive treatment of patients with type 1 diabetes delays the onset of long-term complications. On the basis of the information from two nation-wide quality registers, we investigated to which extent HbA1c values 3-15 months after diagnosis in childhood are related to metabolic control, albuminuria, and retinopathy in early adulthood. In Sweden, physicians register all children and adolescents with type 1 diabetes mellitus in the Swedish Pediatric Quality Registry. After 18 yr of age, people with diabetes are followed by the Swedish National Diabetes Register. We identified 1543 children and adolescents with a mean age of 13.9 yr at diagnosis and a mean duration of type 1 diabetes mellitus of 7.1 yr. Children and adolescents with poor metabolic control (mean HbA1c ≥ 70 mmol/mol (8.6 %)) adjacent to diagnosis had a significantly higher mean HbA1c value years later as adults than did patients with a good metabolic control [<50 mmol/mol (6.7%) (p < 0.001)]. The patients in the high group were also less physically active and smoked more as adults. The proportion of females was higher in the poor metabolic group. Patients with a high mean HbA1c 3-15 months after diagnosis had significantly more often macroalbuminuria and retinopathy in early adulthood. Metabolic control adjacent to the diagnosis of type 1 diabetes in childhood or adolescence can predict metabolic control in early adulthood. It is therefore very important that pediatric diabetes teams identify key factors for successful early metabolic control. Actively using quality registries may be one such factor.

Samuelsson U ，Steineck I ，Gubbjornsdottir S 《-》

Impact of HbA1c Followed 32 Years From Diagnosis of Type 1 Diabetes on Development of Severe Retinopathy and Nephropathy: The VISS Study.

To evaluate HbA1c followed from diagnosis, as a predictor of severe microvascular complications (i.e., proliferative diabetic retinopathy [PDR] and nephropathy [macroalbuminuria]). In a population-based observational study, 447 patients diagnosed with type 1 diabetes before 35 years of age from 1983 to 1987 in southeast Sweden were followed from diagnosis until 2019. Long-term weighted mean HbA1c (wHbA1c) was calculated by integrating the area under all HbA1c values. Complications were analyzed in relation to wHbA1c categorized into five levels. After 32 years, 9% had no retinopathy, 64% non-PDR, and 27% PDR, and 83% had no microalbuminuria, 9% microalbuminuria, and 8% macroalbuminuria. Patients with near-normal wHbA1c did not develop PDR or macroalbuminuria. The lowest wHbA1c values associated with development of PDR and nephropathy (macroalbuminuria) were 7.3% (56 mmol/mol) and 8.1% (65 mmol/mol), respectively. The prevalence of PDR and macroalbuminuria increased with increasing wHbA1c, being 74% and 44% in the highest category, wHbA1c >9.5% (>80 mmol/mol). In comparison with the follow-up done after 20-24 years' duration, the prevalence of PDR had increased from 14 to 27% and macroalbuminuria from 4 to 8%, and both appeared at lower wHbA1c values. wHbA1c followed from diagnosis is a very strong biomarker for PDR and nephropathy, the prevalence of both still increasing 32 years after diagnosis. To avoid PDR and macroalbuminuria in patients with type 1 diabetes, an HbA1c <7.0% (53 mmol/mol) and as normal as possible should be recommended when achievable without severe hypoglycemia and with good quality of life.

Arnqvist HJ ，Westerlund MC ，Fredrikson M ，Ludvigsson J ，Nordwall M ... -  《-》