Effects of Once-Daily and Twice-Daily Dosing
Effects of Once-Daily and Twice-Daily Dosing
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.
Nonadherence to prescribed therapy continues to be a major challenge to the health care system. In the United States, the economic consequences are estimated at $100 billion per year, 30% of which is indirect medical costs. Studies suggest that regimen complexity is an important determinant of nonadherence. Complicated dosing regimens hamper adherence, especially if multiple dosing of multiple drugs is involved. Previous studies, with intervals ranging from 12 weeks to 5 months, have indicated an adherence benefit over the short term of once-daily (OD) dosing versus twice-daily (BID), three-times-daily, and four-times-daily dosing. Cramer et al examined a total of 15 patients in the OD and BID categories, and Detry et al examined 104 patients overall. Pullar et al found greater adherence on an OD regimen (n = 52) but not much better than BID (n = 54); however, these patients with diabetes were followed for 28 days using phenobarbital as a pharmacologic indicator of compliance. An interesting review of adherence among health care professionals by Corda et al revealed a statistically significant advantage achieved through OD dosing (88% adherence) compared with BID (74% adherence) in both the short term and the long term. This may indicate the upper limit of adherence, given the nature of the participants and the use of a self-administered survey for data collection. In a recent Scottish study of 2,920 patients receiving oral hypoglycemic drugs for type 2 diabetes, Morris et al established a highly significant and independent association of an improved adherence index (AI) with OD sulfonylurea dosing and an observed decrease in adherence of 22% for each increase in the frequency of the daily dose over 12 months.
Our research sought to examine the relationship between patient adherence and persistence with therapy patterns using an OD oral antidiabetic extended-release formulation glipizide gastrointestinal therapeutic system (GITS) and a BID oral antidiabetic immediate-release formulation glipizide, and examine whether the dosage frequency or number of tablets per dose influenced the adherence patterns. The goal of the study is to quantify the impact of regimen complexity on adherence in cohorts with type 2 diabetes.
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.
Nonadherence to prescribed therapy continues to be a major challenge to the health care system. In the United States, the economic consequences are estimated at $100 billion per year, 30% of which is indirect medical costs. Studies suggest that regimen complexity is an important determinant of nonadherence. Complicated dosing regimens hamper adherence, especially if multiple dosing of multiple drugs is involved. Previous studies, with intervals ranging from 12 weeks to 5 months, have indicated an adherence benefit over the short term of once-daily (OD) dosing versus twice-daily (BID), three-times-daily, and four-times-daily dosing. Cramer et al examined a total of 15 patients in the OD and BID categories, and Detry et al examined 104 patients overall. Pullar et al found greater adherence on an OD regimen (n = 52) but not much better than BID (n = 54); however, these patients with diabetes were followed for 28 days using phenobarbital as a pharmacologic indicator of compliance. An interesting review of adherence among health care professionals by Corda et al revealed a statistically significant advantage achieved through OD dosing (88% adherence) compared with BID (74% adherence) in both the short term and the long term. This may indicate the upper limit of adherence, given the nature of the participants and the use of a self-administered survey for data collection. In a recent Scottish study of 2,920 patients receiving oral hypoglycemic drugs for type 2 diabetes, Morris et al established a highly significant and independent association of an improved adherence index (AI) with OD sulfonylurea dosing and an observed decrease in adherence of 22% for each increase in the frequency of the daily dose over 12 months.
Our research sought to examine the relationship between patient adherence and persistence with therapy patterns using an OD oral antidiabetic extended-release formulation glipizide gastrointestinal therapeutic system (GITS) and a BID oral antidiabetic immediate-release formulation glipizide, and examine whether the dosage frequency or number of tablets per dose influenced the adherence patterns. The goal of the study is to quantify the impact of regimen complexity on adherence in cohorts with type 2 diabetes.