Adult-onset type 1 diabetes: Predictors of glycaemic control

Aims: Knowledge about adult-onset (AO) type 1 diabetes remains insufficient. We sought to characterize the initial 5 years of AO type 1 diabetes and hypothesized that initial factors predictive of subsequent glycaemic control might exist.

Materials and methods: A retrospective cohort study based on electronic medical records of 280 subjects with newly diagnosed AO type 1 diabetes (>18 years of age, excluding secondary and latent autoimmune diabetes) with available data for the initial 5-year treatment.

Results: Characteristics at diagnosis: 61% men, mean age 37 ± 12 years, BMI 23 ± 3.3 (kg/m2), systolic/diastolic blood pressure: 123 ± 15/76 ± 9 mm Hg and LDL cholesterol: 2.9 ± 0.9 mmol/L. HbA1c decreased from 106 mmol/mol (11.8%) at diagnosis to 52 mmol/mol (6.9%) at 6 months and then increased gradually to 67 mmol/mol (8.3%) after 5 years. Strict glycaemic control (<53 mmol/mol (7%)) was achieved by 66% within 6-9 months and 30% after 5 years. Comparing patients with and without strict glycaemic control after 5 years revealed no differences in HbA1c, C-peptide or any other diabetes-related parameter at the time of diagnosis. However, reaching strict control within 6-9 months after diagnosis was strongly associated with remaining in strict control after 5 years (OR: 9.2 (CI-95% 4.0-20.9; P < 0.0001)). Conversely, patients who did not achieve early strict control were very unlikely to be well controlled after 5 years.

Conclusions: Long-term tight glycaemic control in subjects with AO type 1 diabetes is both achievable and to some extent predictable. Whether alternative strategies shortly after diagnosis would benefit patients with insufficient glycaemic control should be investigated.