Ketoacidosis at diagnosis in childhood-onset diabetes and the risk of retinopathy 20years later.

Aims: To investigate on the relationship between severity of ketoacidosis, an important risk factor for C-peptide preservation, and long-term microvascular complications in childhood-onset type 1 diabetes mellitus (T1DM).

Methods: 230 childhood-onset diabetic patients (177 pre-pubertal), aged 7.0±3.8years followed for at least 15years after their diagnosis, were enrolled. Clinical and laboratory data at diagnosis, and C-peptide levels in a subset of patients, were compared with the severity of retinopathy and nephropathy, after a mean of 19.6±3.8years of disease. Digital retinal photographs were taken in all patients, and centrally graded. Repeated measurements of HbA1c and microalbuminuria for the whole duration of diabetes were collected in over half of the cases.

Results: Out of 230 patients, those with the lowest age at diagnosis had the most severe DKA and clinical conditions (p<0.05), and lower C-peptide levels (p<0.0001) at diagnosis. There was a significant relationship between pH and clinical severity (r=-0.783, p<0.0001), and between pH and C-peptide levels (r=0.278, p<0.05). The severity of ketoacidosis had no relationship with subsequent lifetime HbA1c values and long-term microvascular complications. In logistic regression analysis, the only variables that independently influenced severity of retinopathy were lifetime HbA1c (B=0.838, p<0.001), duration of disease (B=0.208, p<0.005) and age at diagnosis (B=0.116, p<0.05).

Conclusions: The degree of metabolic derangement at diagnosis is not associated with retinopathy and nephropathy in childhood-onset T1DM. Age at diagnosis seems to be an important variable to be considered when evaluating the long-term effects of residual beta-cell function.