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Retrospective Analysis of Liraglutide as Add-On Therapy in Type 2 Diabetes Mellitus: Quantifying the Changes in Insulin Requirements

Clinical pharmacists in VA primary care pharmacy clinics can effectively and safely use liraglutide to reduce hemoglobin A1c and insulin requirements in veterans.
Federal Practitioner. 2019 February;36(2)a:83-87
February 12, 2019|Federal Practitioner
Katherine Czarnowski, PharmD;Chirlie Silver, PharmD;Bryan Wood, PharmD;Patricia Underwood, PhD, NP, RN, CDE;Dhiren Patel, PharmD, CDE, BC-ADM, BCACP
Author and Disclosure Information

Katherine Czarnowski is a Clinical Pharmacist, Bryan Wood is a Pharmacy Residency Director and Clinical Pharmacy Specialist, Patricia Underwood is a Nurse Practitioner in Endocrinology, and Dhiren Patel is a Clinical Pharmacy Specialist, all at VA Boston Healthcare System in Massachusetts. Chirlie Silver is an Adjunct Faculty of Pharmacy Practice at Massachusetts College of Pharmacy and Health Sciences University in Worcester. Dhiren Patel is an Associate Professor of Pharmacy Practice at Massachusetts College of Pharmacy and Health Sciences University in Boston.
Correspondence: Katherine Czarnowski (kczarnowskipharmd@gmail.com)

Author disclosures
Dhiren Patel is on the speaker's bureaus of AstraZeneca, Boehringer Engelheim, Merck, Novo Nordisk, and Valeritas. He also is on the Advisory Board/Consultant for AstraZeneca, Becton Dickinson, Eli Lilly, Merck, and Sanofi. The other authors report no actual or potential conflicts of interest with regard to this article.

Disclaimer
The opinions expressed herein are those of the authors and do not necessarily reflect those of Federal Practitioner, Frontline Medical Communications Inc., the US Government, or any of its agencies. This article may discuss unlabeled or investigational use of certain drugs. Please review the complete prescribing information for specific drugs or drug combinations—including indications, contraindications, warnings, and adverse effects—before administering pharmacologic therapy to patients.

Methods

We performed a retrospective chart analysis to quantify the benefit of using liraglutide as an add-on therapy to basal and bolus insulin regimens in veterans treated at VA Boston Healthcare System (VABHS). The analysis evaluated changes in insulin doses and HbA1c levels when liraglutide was added to these regimens. Patients identified for the study had electronic medication orders for concurrent therapy with liraglutide, insulin glargine, and insulin aspart filled through outpatient VABHS campus pharmacies for at least 3 months between January 2010 and December 2016. Sixty-nine patients who were on basal-bolus insulin for T2DM and who were prescribed liraglutide for treatment intensification were screened for inclusion and exclusion criteria. Data were analyzed at baseline and 3 months after liraglutide treatment.

Study Protocol

The inclusion criteria were patients aged ≥ 18 years, T2DM diagnosis, and therapy with insulin glargine and insulin aspart for at least 3 months before treatment intensi fication with liraglutide. Exclusion criteria were diagnosis of type 1 DM. To accurately quantify mean change in number of insulin units used, the study included patients only if they had been prescribed insulin glargine and insulin aspart before starting liraglutide. All other insulin regimens were excluded. To detect the true change that occurs when liraglutide is added to basal-bolus insulin, the study also excluded patients if they had been previously prescribed another GLP-1 RA. Patients with contraindications to liraglutide, insulin aspart, or insulin glargine were excluded as well. In addition, patients were excluded from the exposed arm if they were injecting < 1.2 mg of liraglutide once daily or if they had been on liraglutide for < 3 months.

Study Outcomes

All 35 patients who met the inclusion and exclusion criteria were included in this retrospective chart review. The primary outcome was determined by changes in HbA1c level and number of insulin doses 3 months after treatment with liraglutide. For each patient, a chart review was performed to determine the amount of insulin added or reduced during the study period. Data were collected at baseline and 3 months after initiation of liraglutide.

 

Statistical Analysis

Statistical analyses were performed with SPSS Version 20.0 (IBM, Armonk, NY). Population characteristics and study outcomes with normal distribution were compared using a paired t test and are reported as means with standard deviations. Nonnormally distributed variables (bolus insulin, HbA1c level) were compared using the nonparametric Wilcoxon rank sum test and are reported as median values with interquartile ranges. Normality was tested with the Shapiro-Wilk test. The primary outcome evaluated was change in number of insulin units used. Secondary outcomes included change in HbA1c level and change in body weight. A Bonferroni correction for multiple comparisons was used to prevent type I error. Significance at the Bonferroni-corrected level of .01 (.05/5 = .01) is indicated.

Results

Patients were included if they were previously on insulin glargine and insulin aspart before starting liraglutide for treatment intensification. 

Although 69 patients matched the initial search, only 35 were included in the analysis owing to insufficient duration of liraglutide therapy (Figure 1).  Those patients were not on liraglutide therapy for at least 3 months with HbA1c results to allow for an appropriate analysis.

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