The aim of this study was to evaluate the metabolic effects of continuous subcutaneous insulin infusion (CSII) with flexible multiple daily insulin (FMDI; premeal lispro + bedtime glargine) therapy as determined by glycosylated hemoglobin (HbA1c), body mass index (BMI), and hypoglycemic episodes in a group of patients who made the transition from multiple daily insulin (premeal lispro + bid ultralente) to either CSII or FMDI therapy. Data from 40 (27 female and 13 male) patients (10.1-17.8 years of age) who were on CSII and 40 age- and gender-matched (27 female and 13 male) patients (10.3-17.3 years of age) who were on FMDI were collected during regularly scheduled visits at a similar frequency over a 1-year period. The total daily insulin dose did not change in CSII (0.97 +/- 0.24 vs 0.91 +/- 0.22 U/kg) and FMDI (0.98 +/- 0.21 vs 0.97 +/- 0.21 U/kg) patients, whereas the bolus:basal insulin ratio was significantly increased in both CSII (1.01 +/- 0.43 vs 1.32 +/- 0.52) and FMDI (1.07 +/- 0.0.41 vs 1.29 +/- 0.47) patients. The total cohort of CSII patients showed a decrease in HbA1c from 8.4 +/- 1.0% to 7.8 +/- 0.8%, whereas the FMDI cohort did not show a significant change in HbA1c (8.5 +/- 1.1% to 8.2 +/- 0.9%). However, 40% of the CSII group and 22.5% of the FMDI group showed > or =1.0% improvement in HbA1c. Also, a similar number of patients in CSII (52.5%; 8.0 +/- 1.1 to 7.2 +/- 0.5%) and FMDI (47.5%; 8.0 +/- 0.5% to 7.5 +/- 0.4%) maintained or achieved target HbA1c values <8.0%. The BMI increased significantly in the CSII group (21.6 +/- 3.2 vs 23.0 +/- 3.0 kg/m2) but did not change in the FMDI group (21.9 +/- 3.9 vs 22.6 +/- 3.8 kg/m2). There was a significant reduction in the rate of severe hypoglycemia (events/100 patient-years) in both cohorts: 20.6 to 8.2 in the CSII and 18.8 to 7.5 in the FMDI. Similarly, the rate of moderate hypoglycemia decreased in both CSII (68.3-35.4) and FMDI (56.3-30.4). CSII therapy resulted in a significant improvement in HbA 1c in the entire group, whereas FMDI therapy improved HbA1c in only a subgroup of patients. However, almost half of the patients in each of the treatment groups maintained or achieved target glycemic control. Both CSII and FMDI treatment groups demonstrated a decreased rate of hypoglycemia without an abnormal increase in BMI. Although the design of this study does not allow direct comparison of the metabolic effects of CSII and FMDI therapies, both regimens seem to be superior to basal ultralente and lispro multiple daily insulin regimen and offer desirable therapeutic alternatives in pediatric diabetes care.