The addition of glipizide to insulin therapy in type-II diabetic patients with secondary failure to sulfonylureas is useful only in the presence of a significant residual insulin secretion.
The present study aimed at 1) investigating the effect of a combined insulin + glipizide treatment on the metabolic control (HbA1c levels) and insulin requirements (Biostator assessment) in ten non-obese Type-II diabetic patients with recent secondary failure to sulfonylureas; and 2) characterizing the relative contributions of changes in endogenous insulin secretion (C-peptide response) and insulin sensitivity (insulin-induced glucose disposal in clamped conditions) to this effect. The patients were treated in a randomized cross-over order with either insulin alone or insulin + glipizide (3 X 10 mg/day) during two periods averaging 6 weeks each. Mean HbA1c levels were similar in both experimental conditions (8.2 +/- 0.6 vs 7.9 +/- 0.6%, NS). In fact, during the combined therapy, HbA1c levels decreased in five subjects (from 8.6 +/- 0.7 to 7.1 +/- 0.5%; 'responder'), but not in the five others ('non-responders'); the 20-h Biostator insulin infusion was significantly decreased in the responders (29%; P less than 0.05), but not in the non-responders. Basal (0.271 +/- 0.086 vs 0.086 +/- 0.017 nmol/l; P less than 0.05) and post-glucagon (0.468 +/- 0.121 vs 0.180 +/- 0.060 nmol/l; P less than 0.05) C-peptide plasma levels were significantly higher in the responders than in the non-responders; in addition, glipizide significantly increased basal C-peptide concentrations in the responders only (+68%; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Castillô
M
M
Division of Diabetes, University of Liège, Belgium.
Scheen
A J
AJ
Paolisso
G
G
Lefèbvre
P J
PJ
D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000097:blood; D002986:Clinical Trials as Topic; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D004359:Drug Therapy, Combination; D005260:Female; D005913:Glipizide / Q000008:administration & dosage*; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007328:Insulin / Q000008:administration & dosage* / Q000378:metabolism; D000078790:Insulin Secretion; D008297:Male; D008875:Middle Aged; D013453:Sulfonylurea Compounds / Q000008:administration & dosage*
D001786:Blood Glucose; D002096:C-Peptide; D005913:Glipizide; D006442:Glycated Hemoglobin; D007328:Insulin; D013453:Sulfonylurea Compounds