Objective: To assess the prevalence and characteristics of patients with type 1 diabetes (T1D) who dose bolus insulin postprandial (PostP) versus preprandial (PreP).
Methods: Data for this cross-sectional study were obtained from 21,533 participants in the T1D Exchange Registry. Data were drawn from the enrollment questionnaire. Patients who dosed 'immediately before meal' or 'several minutes before meal' were classified as PreP. Patients who dosed 'during meal' or 'after meal' were classified as PostP. Data reported (PostP vs. PreP) are mean ± SD and percentage, as appropriate.
Results: After exclusion of patients who did not answer the dose-timing question or who selected 'not given regularly' or 'depends on glucose level prior to meal,' (4,229 of 25,762), 21,533 patients were included in the study. Ninety-nine percent of patients used rapid-acting insulin analogues; 32% dosed insulin PostP. Compared to PreP, children <18 years of age dosing PostP were characterized by higher glycated hemoglobin (HbA1c) (8.7 ± 1.5% [72 ± 16.4 mmol/mol] vs. 8.4 ± 1.7% [68 ± 18.6 mmol/mol]), larger insulin dose (1.2 ± 0.7 IU/kg/day vs. 1.1 ± 0.7 IU/kg/day), greater prevalence of history of hypoglycemia, and diabetic ketoacidosis. Adults who dosed PostP were characterized by younger age (33.0 ± 15.3 years vs. 39.5 ± 16.6 years), higher HbA1c (8.3 ± 1.5% [67 ± 16.4 mmol/mol] vs. 7.8 ± 1.5% [62 ± 16.4 mmol/mol]), and larger insulin dose (1.0 ± 0.6 IU/kg/day vs. 0.9 ± 0.5 IU/kg/day) than PreP.
Conclusion: This study reveals that a large proportion of patients dose bolus insulin PostP. Despite the use of current rapid-acting insulin analogues, patients who dose PostP are characterized by poorer glycemic control in all patients and a greater prevalence of history of severe hypoglycemia and diabetic ketoacidosis in children.
Abbreviations: BMI = body mass index; CGM = continuous glucose monitoring; DKA = diabetic ketoacidosis; HbA1c = glycated hemoglobin; PostP = postprandial; PreP = preprandial; SMBG = self-monitored blood glucose; T1D = type 1 diabetes.