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DSTXXX10.1177/1932296816658746Journal of Diabetes Science and TechnologyJacob et al

Original Article

Prescription Patterns and the Cost of Antihyperglycemic Drugs in Patients With Type 2 Diabetes Mellitus in Germany

Journal of Diabetes Science and Technology 2017, Vol. 11(1) 123­–127 © 2016 Diabetes Technology Society Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1932296816658746 journals.sagepub.com/home/dst

Louis Jacob, PhD1, Christian von Vultee, PhD2, and Karel Kostev, DMSc, PhD2

Abstract Aims: The goals were to analyze prescription patterns and the cost of antihyperglycemic drugs in patients with type 2 diabetes (T2DM) treated in Germany in 2015. Methods: This study included 36382 patients aged 40 years or over treated in general practices (GPs) and diabetologist practices who were diagnosed with T2DM in 2015. Nine different families of antihyperglycemic therapy were included in the analysis. Demographic data included age, gender, and type of health insurance coverage. Clinical data included HbA1c level, body mass index (BMI), and the number of T2DM complications. The annual antihyperglycemic treatment cost per patient was calculated based on pharmacy retail prices. The multivariate regression analysis was fitted to estimate the adjusted treatment cost differences. Results: The percentage of T2DM patients receiving antihyperglycemic treatments was 87.6. This share was slightly higher in men than in women (89.1% vs 86.0%). Interestingly, the share of people treated with antihyperglycemic drugs decreased with age yet increased with HbA1c levels, BMI, and the number of complications. The average annual cost of antihyperglycemic drugs amounted to €498. It was significantly higher in men than in women (difference of €22). It was also significantly higher in individuals with private health insurance coverage than in people with public health insurance coverage (difference of €153). The annual cost decreased with age. It is compelling to note that this cost increased with HbA1c levels and BMI. Finally, the annual cost also increased with the number of complications. Conclusions: The share and the cost of antihyperglycemic treatments vary with gender, age, type of health insurance coverage, HbA1c levels, BMI, and the number of complications. Keywords type 2 diabetes, therapy cost, primary care, HbA1c, BMI, complication

Diabetes is a chronic disease which affects around 8.3% of the worldwide population.1,2 It is estimated that 1 in every 13 persons in Germany has diabetes.3 Type 2 diabetes mellitus (T2DM) is found in 90% of individuals with diabetes.4 The current annual German cost associated with T2DM of approximately €11.8 billion in 2010 will exceed €21 billion in 2040, underscoring the major burden of diabetes in this country.5 Reduction of blood glucose levels in T2DM patients is important since it can prevent microvascular and macrovascular complications.6-8 If these levels remain high despite the introduction of lifestyle measures such as weight control and physical activity, oral antihyperglycemic medications and insulin treatments can be used in people with T2DM. Several studies have targeted the prescription of antihyperglycemic

drugs and the cost of these medications in Germany.9-10 In 2007, Rathmann and colleagues discovered that there had been a 100% increase in the average cost for antidiabetic medication between 1994 (€86.7) and 2004 (€172.1).9 More recently, Tamayo et al further found regional and individual social disparities in the cost of overall and newer antihyperglycemic medications unexplained by other confounders.10 Although these works have shed light on medical and 1

Department of Biology, École Normale Supérieure de Lyon, Lyon, France IMS Health, Frankfurt, Germany

2

Corresponding Author: Karel Kostev, DMSc, PhD, IMS Health, Epidemiology, Darmstädter Landstraße 1089, 60598 Frankfurt am Main, Germany. Email: [email protected]

124 economic aspects of the treatment of T2DM in Germany in the past decades, they may be obsolete and may not reflect the status of current antihyperglycemics prescriptions in this country. Consequently, the goal of the present study was to analyze prescription patterns and the cost of antihyperglycemic drugs in T2DM patients treated in German general and diabetologist practices in 2015.

Methods Database The Disease Analyzer database (IMS HEALTH) compiles drug prescription, diagnosis, basic medical, and demographic data obtained directly and in anonymous format from computer systems used in the practices of general practitioners. Diagnoses (ICD-10), prescriptions (Anatomical Therapeutic Chemical [ATC] Classification System), and the quality of reported data have been monitored by IMS based on a number of criteria (eg, completeness of documentation, linkage between diagnoses and prescriptions). In Germany, the sampling methods used for the selection of physicians’ practices were appropriate to obtain a representative database of primary care practices.11 Prescription statistics for several drugs were very similar to data available from pharmaceutical prescription reports.12 The age groups for given diagnoses in Disease Analyzer also agreed well with those in corresponding disease registries.11 Finally, this database has already been used in several studies focusing on diabetes.2,12-14

Study Population The present study included 36382 patients aged 40 years or over with a T2DM diagnosis in 2015. In all, 29779 patients were treated by GPs and 6603 by diabetologists. Nine different families of antihyperglycemic therapy were included in the analysis: human insulins and analogues (ATC: A10C), sulphonylureas (A10H), biguanides (A10J), glitazones (A10K), alpha-glucosidase inhibitors (A10L), glinides (A10M), dipeptidyl peptidase-4 (DPP-4) inhibitors (A10N), sodium-glucose cotransporter 2 (SGLT-2) inhibitors (A10P), and glucagon-like peptide 1 (GLP-1) agonists (A10S). Demographic data included age, gender, and type of health insurance coverage (public or private). Clinical data included HbA1c levels, body mass index (BMI), and the number of T2DM complications, which comprised coronary heart disease (CHD, ICD 10: I24-25), myocardial infarction (I21-23), stroke/transient ischemic attack (I63-64, G45), peripheral arterial disease (PAD, I73.9, E11.5), polyneuropathy (E11.4), retinopathy (E11.3), and renal complication (N18-19, E11.2). BMI and HBA1c were estimated based on the last documented value in 2014.

Journal of Diabetes Science and Technology 11(1)

Statistical Analyses The study sample was stratified by age, gender, type of health insurance coverage, HBA1c levels, BMI, and the number of T2DM complications. The share of patients who received antihyperglycemic treatments was further estimated. The annual antihyperglycemic treatment cost per patient was calculated based on pharmacy retail prices. The multivariate regression analysis was fitted with the annual antihyperglycemic medication cost as dependent variable, and age, gender, type of health insurance coverage, HBA1c levels, BMI, and number of complications were used as predictor variables to estimate the adjusted treatment cost differences. An additional regression model included antihyperglycemic drug classes as dependent variables to estimate the cost changes depending on the therapy received. Analyses were carried out using SAS version 9.3.

Results In 2015, 87.6% of T2DM patients received antihyperglycemic treatments (Table 1). This share was slightly higher in men than in women (89.1% vs 86.0%). It is interesting to note that the share of people who received antihyperglycemic drugs decreased with age (≤60 years: 89.1% vs >80 years: 83.3%) yet increased with HbA1c levels (89.0%). Table 2 displays the average cost of antihyperglycemic medications per patient in 2015 and the results of the regression model. This cost amounted to €498 (SD €590) for the overall population. It was significantly higher in men than in women (adjusted difference of €22). It was also significantly higher in individuals with private health insurance coverage than in people with public health insurance coverage (adjusted difference of €153). The annual cost decreased with age, from €548 in patients aged 60 years or younger to €388 in patients aged over 80 years (adjusted difference of €168). Interestingly, the cost increased with HbA1c levels and BMI (HbA1c