Retrospective comparative analysis of metabolic control and early complications in familial and sporadic type 1 diabetes patients

Background: Genetic susceptibility and lifestyle are associated with glycemic control and diabetic complications in type 1 diabetes (T1D). Objectives: To investigate metabolic control and occurrence of acute and microvascular complications among familial and sporadic T1D patients. Patients and Methods: Retrieved from our institutional registry of new T1D cases for the years 1979-2008 were 226 familial patients belonging to 121 families (58 parent-offspring, 63 sib-pairs) and 226 sporadic cases matched for age, gender, and year of diagnosis. Extracted from medical files were clinical course and therapeutic regimen. Results: Mean age at diagnosis of diabetes of the cohort was 10.8 ± 5.7 years. Throughout follow-up (11.1 ± 8.7 years) mean HbA1c values were significantly higher in familial than in sporadic cases (8.18% ± 1.15% vs. 7.85% ± 1.15%, p = 0.005). Diabetic ketoacidosis (DKA) rates were higher in familial than sporadic cases (2.8 vs. 1.9 events per 100 patient-years; incidence rate ratio (IRR) = 1.5, 95% CI [1.03, 2.22, p = 0.03]). Severe hypoglycemia events per 100 patient-years were comparable in familial and sporadic groups (3.7 vs. 4.0 events); sib-pairs had higher rates than parent-offspring (4.8 vs. 2.4 events; (IRR) = 2, 95% CI [1.03, 3.25, p = 0.03]). The percentage of patients with microvascular complications was similar in the familial (21.7%) and sporadic (26.7%) groups. In both familial and sporadic cases the most significant predictor for metabolic control and microvascular complications was diabetes duration; a higher mean HbA1c level was the predictor for DKA events. Conclusions: The worse metabolic control and increased rate of DKA in familial T1D patients as compared to those in the sporadic T1D patients warrant intensified surveillance in this population.