Introduction. The results of a 25-year observational program to assess the effect of glycated hemoglobin variability on the development of microvascular complications in patients with type 1 diabetes mellitus are presented.Objective: This study aimed to evaluate the effect of glycated hemoglobin (HbA1c) variability on the development of microvascular complications in patients with type 1 diabetes mellitus (DM1) and disease duration of 25 years.Materials and methods: A retrospective analysis of the database of patients with DM1 was performed from the moment of the disease manifestation until the time of the last visit. Determination of HbA1c level is carried out using parameters certified in accordance with the National Standard for Glycohemoglobin Standardization (NGSP) or the International Federation of Clinical Chemists (IFCC). HbA1c variability was determinated by average current HbA1c, average of longitudinal HbA1c (from the manifestation to the last visit – 2019), median and maximum of difference in changes of HbA1c (median and max∆HbA1c). Statistical analysis was performed by IBM SPSS Statistics ver.22. A statistically significant difference is the value p < 0.05.Results. A total of 88 patients were enrolled in this study, they were divided in 3 groups depending on the registered microvascular complications (MVC): without MVC (n = 38), isolated MVC (retinopathy or nephropathy) (n = 25) and multiple MVC (retinopathy and nephropathy) (n = 25). Clinical characteristics [median (25; 75 percentile)]: age of manifestation of DM1 is 9 years (5; 12), age of patients at the time of the last visit is 33 years (29; 35), duration of DM1 is 24 years (20; 27), body mass index 24 kg/m2 (21; 25). Medication: basal-bolus insulin therapy (n = 82) or pump insulin therapy (n = 6). The average level of longitudinal HbA1c for the three groups was: 8% (7.6; 8.9), 8.5% (7.9; 8.9), 8.6% (7.8; 10), p = 0.2. Average of current (at the time of the last visit) HbA1c – 8.2% (7.2; 9.0), 8.1% (7.5; 9.0), 8.4% (7.3; 9.7), p = 0.4. Statistically significant differences were determined in the group without complications and in the group with multiple complications between the levels of maxΔ HbA1c 2.3% (1.8; 2.8) vs 4.7% (3.2; 5.6), p < 0.0001 and median Δ HbA1c 0.7% (0.6; 0.9) vs 1.4% (1; 1.7), р < 0.0001. There were no statistically significant relationships between the maximum and medianΔ HbA1c in the groups without complications and in the group with isolated complications.Conclusions: Longitudinal HbA1c and current HbA1c are not associated with the development of microvascular complications. The potential role in the development of microvascular complications was determined for the maximum and median Δ HbA1c.
The effect of glycated hemoglobin variability on the development of microvascular complications in patients with type 1 diabetes
