Subanalyses of Elderly Type 2 Diabetes Patients or Type 2 Diabetes Patients With Renal Impairment

Background: In January 2012, the US Food and Drug Administration approved a once-weekly form of exenatide, Bydureon, for the treatment of type 2 diabetes mellitus. Evidence from clinical trials suggested that Bydureon improves glucose control with low risk of hypoglycemia. Bydureon does not require a dose titration as necessary for other glucagon-like peptide-1 agonists (GLP-1RAs), and appears to have other advantages, such as reducing insulin resistance, reducing weight, and improving blood pressure and lipid profiles. However, the degree to which these advantages of Bydureon lead to improve outcomes in patients with renal impairment or who are elderly is unknown.

Aims: The aim of this study is to evaluate the effectiveness and tolerability of Bydureon relative to basal insulin initiated as first-ever injectable therapeutic regimens among elderly patients and patients with renal impairment.

The specific study objectives are as follows:

• To quantify the effectiveness of Bydureon initiation relative to initiation of basal insulin, on improving:
• Glycated hemoglobin (HbA1c)
• Weight (body mass index (BMI))
• HbA1c simultaneous to reduction in weight
• Blood pressure and lipid profiles
• To examine the tolerability of Bydureon initiation relative to initiation basal insulin, on the occurrence of :
• Hypoglycemia
• Gastrointestinal symptoms (nausea, vomiting, diarrhea, and constipation)
• Change in the markers for renal function (estimated glomerular filtration rate (eGFR), serum creatinine, and albumin/creatinine ratio (ACR), and the stability of liver function test (AST, ALT) and standard blood counts (WBC, RBC, HCT, Hgb, PLT)
• To examine these measures of effectiveness and tolerability within potentially vulnerable subgroups of Bydureon and basal insulin initiators:
• T2D patients with renal impairment
• Elderly T2D patients Study Population and Design: This retrospective cohort study will use Optum's EHR data from July 2011 through March 2015 and identify injectable-naive T2D patients who initiated either Bydureon or basal insulin during the accrual period, January 2012 and January 2015. Injectable-naive T2D patients will be indetified. Propensity score methods will be used to match Bydureon initiators with basal insulin initiators.

Subgroup Comparisons: Within the EHR data, serum creatinine values will be used to calculate the eGFR using an equation developed by the Chronic Kidney Disease (CKD) Epidemiology (EPI) Collaboration, called the CKD-EPI Equation.

Renal Impairment: Patients will be stratified by eGFR ranges in baseline indicative of the renal impairment, as follows:

• Normal, eGFR ≥ 90.00 mL/min/1.73m2
• Mild impairment, 60.00 < eGFR < 89.99 mL/min/1.73m2
• Moderate and Severe impairment, eGFR < 59.99 mL/min/1.73m2

Elderly T2D Patients: Elderly subgroups will be defined as 65+ years of age. Patients will be stratified by age on index date, as follows:

• < 65 years
• 65 to 74 years
• 75+ years Outcomes and Analysis: To measure the effectiveness of Bydureon relative to basal insulin are changes in HbA1c and body weight, as well as changes in HbA1c and simultaneous reduction in weight. Changes in BMI, lipid profiles, and blood pressure will be assessed. These variables are part of the clinical and laboratory data in the EHR. Each outcome will be evaluated for completeness, multiply imputed, and reported across standardized time intervals. HbA1c, weight and BMI will be summarized in baseline and quarterly (3-month intervals) in the first year following drug initiation. Lipid measurements and blood pressure will be summarized in baseline and bi-annually (6-month intervals) in the first year following drug initiation.

To assess drug tolerability, incidence of hypoglycemia, and gastrointestinal symptoms (nausea, vomiting, diarrhea, and constipation) will be calculated. These outcomes will be ascertained using an ICD-9 algorithm applied to the structured fields and by extracting mentions of hypoglycemia using a natural language processing (NLP) algorithm developed by Optum and applied to the free text clinical notes available in the data. In addition the stability of renal function evaluated by change in eGFR, or albumin/creatinine ratio (ACR); the change in serum hepatic enzymes [aspartate aminotransferase (AST), alanine aminotransferase (ALT)], and hematologic measures [red blood cells counts (RBC), white blood cell counts (WBC), platelets (PLT), hemoglobin (Hgb) and hematocrit (Hct) will be evaluated. Each of these laboratory values will be evaluated for completeness, multiply imputed, and reported across standardized time intervals. eGFR and ACR are summarized in baseline and quarterly (3-month intervals) in the first year following drug initiation. Hepatic enzymes and hematologic measures are summarized in baseline and semi-annually (6-month intervals) in the first year following drug initiation.

Inclusion criteria

• At least 18 years old;
• had received care documented in EHR (including at least one out-patient provider visit) for a minimum of 6-months prior index date;
• had at least one diagnosis of Type 2 diabetes (ICD-9-CM: 250.X0 or 250.X2) prior to and including the date of the study drug initiation, with no prior diagnosis of type1 diabetes (ICD-9-CM: 250.X1 or 250.X3), or gestational diabetes within the 6-months prior to index date;
• No evidence of prior injectable antidiabetic treatment, specifically no dispensing of a GLP-1-RA or any insulin during the 6-months baseline period prior to study drug initiation

Exclusion criteria

• Prior diagnosis of type 1 diabetes (ICD-9-CM: 250.X1 or 250.X3), or gestational diabetes within the 6-months prior to index date;
• Prior dispensing of a GLP-1RA or any insulin
• Missing data on renal function defined by eGFR or age