Initiation of insulin therapy in elderly patients taking oral antidiabetes drugs

Abstract

Methods Data sourcesUsing the database of the Quebec health insurance board (La Régie de l'assurance maladie du Québec) and the Quebec registry of hospital admissions (Maintenance et exploitation des données pour l'étude de la clientèle hospitalière [MedEcho]), we performed a population-based inception cohort study. The health insurance plan of Régie de l'assurance maladie du Québec covers all permanent residents of the province for both medical services and hospital admissions. Its public drug plan covers recipients of welfare, those not eligible for a private group plan for drug insurance and all people aged 65 years and over who do not live in an institution. This drug-plan database is accurate for prescription claims.12 In 2006, a total of 3.2 million people (out of a population of 7.5 million) were beneficiaries of this drug plan.A unique encrypted health number was used to link the databases and the registry at the patient level. Initiation of insulin therapy in elderly patients taking oral antidiabetes drugsFrom the Unité de recherche en santé des populations (Pérez, Moisan, Sirois, Grégoire), Centre de recherche du centre hospitalier affilié universitaire de Québec; the Faculty of Pharmacy (Moisan, Sirois, Poirier, Grégoire), Université Laval, and the Quebec Heart and Lung Institute (Poirier), Hôpital Laval, Québec, Que. Background:We sought to estimate the rate of initiation of insulin therapy among elderly patients using oral antidiabetes drugs and to identify the factors associated with this initiation. Methods:We conducted a population-based cohort study involving people aged 66 or more years who were newly dispensed an oral antidiabetes drug. Individuals who had received acarbose or a thiazolidinedione were excluded. The rate of insulin initiation was calculated by use of the KaplanMeier method. Factors associated with insulin initiation were identified by multivariable Cox regression analyses. Results:In this cohort of 69 674 new users of oral antidiabetes drugs, insulin was initiated at rate of 9.7 cases per 1000 patient-years. Patients who had initially received an insulin secretagogue (rather than metformin), who were prescribed an oral antidiabetes drug by an endocrinologist or an internist, who received higher initial doses of an oral antidiabetes drug, who received oral corticosteroids, used glucometer strips, or were admitted to hospital in the year before initiation of oral antidiabetes therapy, or who received 16 or more medications were more likely than those without these characteristics to have insulin therapy initiated. In contrast, patients who received thiazides or who used up to 12 medications (v. none) were less likely to have insulin therapy initiated.Interpretation: Several factors related to drugs and health services are associated with the initiation of insulin therapy in elderly patients receiving oral antidiabetes drugs. It is unclear whether these factors predict secondary failure of oral antidiabetes drugs or instead reflect better management of type 2 diabetes.

Progression to insulin therapy among patients with type 2 diabetes treated with sitagliptin or sulphonylurea plus metformin dual therapy

“…Results were in line with previous literature that found that patients treated with sulphonylureas had a higher likelihood of insulin use, and earlier insulin initiation, compared with patients treated with other OADs such as metformin [4][5][6][7]14,16]. Only one previous study has assessed the risk of insulin initiation among patients treated with DPP-4 inhibitors specifically, reporting similar findings.…”

“…These include patient demographics, such as younger age [8][9][10][11][12][13], lower income [13] and non-Hispanic race/ethnicity [9], as well as higher glycated haemoglobin (HbA1c) [8][9][10][11][12][13][14][15], fasting plasma glucose [11], serum creatinine [14], duration of T2DM [9,13] and presence of comorbidities and diabetesrelated complications, including depression, lipid disorders, micro-and macrovascular complications and overall chronic disease score [4,7,9,11,13]. Patients who are treated with higher doses of OADs [16], initiate with more than one agent [13], have greater concomitant medication use [11,16], and who have a history of hospitalization are also at increased risk [16]. Furthermore, being treated by a specialist has been shown to be positively associated with insulin use [9,13,16].…”

“…Patients who are treated with higher doses of OADs [16], initiate with more than one agent [13], have greater concomitant medication use [11,16], and who have a history of hospitalization are also at increased risk [16]. Furthermore, being treated by a specialist has been shown to be positively associated with insulin use [9,13,16]. Some of these factors may affect treatment patterns more than the underlying biology of disease.…”

Initial Sulfonylurea Use and Subsequent Insulin Therapy in Older Subjects with Type 2 Diabetes Mellitus

“…The annualized rates of insulin initiation were approximately 1.5% for those started with metformin and 3% for those started with sulfonylureas. These rates on insulin initiation are generally similar to the annualized rates reported for a Canadian (1%) and a Swedish cohort (3.5%) of patients who initiated therapy with an oral antihyperglycemic agent [13, 14]. Furthermore, initiating treatment with sulfonylurea monotherapy was significantly associated with a shorter time to insulin use compared to initiating with metformin monotherapy.…”

“…In a cohort of older Canadian subjects with T2DM (age ≥ 66 years), new users of insulin secretagogues (including sulfonylureas) were more likely to initiate insulin therapy than new users of metformin [13]. In a Swedish cohort of subjects with T2DM, initial metformin monotherapy use was associated with a lower probability of initiating insulin relative to non-metformin therapy (primarily sulfonylurea) [14].…”