Effects of once-daily and twice-daily dosing on adherence with prescribed glipizide oral therapy for type 2 diabetes

South Med J. 2002 Jan;95(1):68-71.


Background: We evaluated differences in adherence and persistence with prescribed therapy of once-daily (OD) dosing compared with twice-daily (BID) dosing of glipizide in patients with type 2 diabetes.

Methods: The study cohort was derived from a pharmacy benefit manager claims database. Patients new to extended-release gastrointestinal therapeutic system (GITS) and immediate-release glipizide therapy were identified and followed for 1 year. Adherence indices (AIs) were calculated and persistence curves were constructed.

Results: Adherence indices rates were 60.5% in the GITS OD cohort and 52.0% in the BID cohort. Rates of persistence at 12 months were 44.4% in the GITS OD cohort vs 35.8% in the BID cohort.

Conclusion: Initiation of OD pharmacotherapy results in better adherence and persistence compared with a BID regimen, despite a greater daily pill burden in the OD cohort. These data suggest that dosing frequency exerts a greater impact on patient adherence and persistence than number of tablets per dose.

MeSH terms

  • Administration, Oral
  • Adult
  • Age Factors
  • Aged
  • Cohort Studies
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Drug Delivery Systems*
  • Female
  • Glipizide / administration & dosage*
  • Glipizide / therapeutic use
  • Humans
  • Hypoglycemic Agents / administration & dosage*
  • Hypoglycemic Agents / therapeutic use
  • Male
  • Middle Aged
  • Patient Compliance*
  • Retrospective Studies
  • Sex Factors
  • Time Factors
  • Treatment Outcome


  • Hypoglycemic Agents
  • Glipizide