Linagliptin

Ten-week-old female C57BL/6N mice (n = 57) were purchased from Charles River (Boston, MA). The study design comprised four individual studies (Table 1) in which obesity was induced by feeding the mice a high-fat diet (60 kcal% fat; Research Diets D12492, Open Source Diets, New Brunswick, NJ) for 2, 3 or 4 months, depending on the study protocol. Chow-fed mice (n = 15) were used as controls for all the studies. Therapeutic intervention with linagliptin or vehicle was initiated after the high-fat feeding period for 3 or 4 additional weeks. Linagliptin (3 or 30 mg/kg in 0.5% Natrosol) was administered orally once-daily between 0800 and 0900 using a cannula; Natrosol alone was used as vehicle control. Clamp studies and magnetic resonance spectroscopy (MRS) studies used 15 and nine animals per group, respectively. Fed plasma glucose concentrations were measured once weekly before treatment. Experiments were performed in accordance with the rules for animal care of the local government authorities and were approved by the animal care and use committee of Leipzig University as well as by the animal care committee of the Bezirksregierung Leipzig, Germany (Approval ID: TVV 27/08).

The CARMELINA^® study is a multi-national, randomized, double-blind, placebo-controlled clinical trial conducted in 27 countries (ClinicalTrials.gov identifier: NCT01897532) (Fig. 2). CARMELINA^® is an event-driven trial designed to assess the impact of linagliptin versus placebo on CV and kidney outcomes in a population of patients with T2D enriched for both macrovascular and kidney microvascular risk. The study is designed to run until at least 611 participants have had an adjudicated primary-outcome event. The study protocol was approved by institutional review boards, independent ethics committees and competent authorities according to national and international regulations. CARMELINA^® was conducted in accordance with the ICH Harmonised Tripartite Guideline for Good Clinical Practice. All participants provided written informed consent prior to entering the study.Fig. 2

Design of the CARMELINA^® trial. *Additional glucose-lowering therapy may be given on top of study medication if HbA1c > 7.5%; investigators are encouraged to treat all other CV risk factors in accordance with local or regional standards of care. ^†Participants who stop study drug early are observed until study end (not just until 30 days after the end of treatment with study drug). CV cardiovascular, HbA1c glycated hemoglobin A1c

Within the database, a separate cohort was created for each pairwise comparison of SGLT2i versus an alternative non-gliflozin class. Cohort membership required patients to be new users of the study medications of interest (defined as no use of the medications in the 365-day washout period preceding medication initiation), be older than 65 years of age at cohort entry and have no evidence of gestational or type 1 diabetes (T1D), cancer, end-stage renal disease, or human immunodeficiency virus infection. With the sole exception of heart failure phenotype (see below), all baseline covariates including eligibility criteria and patient characteristics were assessed in the 365 days prior to the date of medication initiation.
The study cohort was further restricted to patients with the presence of HHF with ICD codes corresponding to HFrEF (ICD-9: 428.2× or ICD-10: I50.2×) or HFpEF (ICD-9: 428.3 × or ICD-10: I50.3×) in either the first or second position of the inpatient discharge diagnosis using all available lookback. The positive predictive value for this approach for identifying patients with HFrEF is 72% and 90% using ejection fraction [EF] thresholds of ≤ 40% and ≤ 50%, respectively, and 92% for HFpEF for an EF threshold of > 50% [19 ]. Patients with evidence of both or neither HF subtypes were excluded from analyses.
The study was comprised of four pairwise comparison cohorts, which included patients with: (1a) HFrEF initiating SGLT2i versus DPP4i; (1b) HFrEF initiating SGLT2i versus GLP-1RA; (2a) HFpEF initiating SGLT2i or DPP4i; and (2b) HFpEF initiating SGLT2i or GLP-1RA. For SGLT2i versus DPP4i comparisons, patients using combination empagliflozin–linagliptin therapy were excluded from analysis. Further, individuals initiating SGLT2i and the comparator on the same day were also excluded from analyses. Patients meeting the inclusion and exclusion criteria could contribute to each cohort only once, but the same patient could be included in more than one cohort.

The study population included patients 18 years and older who initiated treatment with a SGLT2i (canagliflozin, dapagliflozin, empagliflozin, or ertugliflozin) or a DPP-4i (alogliptin, saxagliptin, linagliptin, or sitagliptin) between April 1, 2013 (consistent with the US Food and Drug Administration [FDA] approval of the first SGLT2i), and June 30, 2021. Treatment with DPP-4i was selected as the comparator because these medications are also frequently used as second-line therapy for T2D, have similar out-of-pocket costs as SGLT2i but a different mechanism of action, which does not involve inhibition of kidney glucose reabsorption and osmotic diuresis, and have shown no association with atherosclerotic cardiovascular outcomes. Cohort entry was the day of the first filled prescription of either SGLT2i or DPP-4i, with no use in the previous 6 months. Study eligibility was limited to patients with at least 6 months of continuous health plan enrollment, a recorded T2D diagnosis before cohort entry, and at least 1 HbA_1c laboratory result recorded within 3 months before cohort entry. We excluded patients with records of type 1, secondary, or gestational diabetes; malignant neoplasms; end-stage kidney disease; kidney replacement therapy; no laboratory results for creatinine; or nursing home residence within 6 months preceding cohort entry (eFigure 1 and eTable 2 in Supplement 1). Based on the most recent HbA_1c baseline value, we identified 3 different subcohorts which comprised patients with controlled (HbA_1c <7.5%), above-target (HbA_1c 7.5%-9%), or elevated (HbA_1c >9%) glycemia, respectively (to convert percentage of total hemoglobin to proportion of total hemoglobin, multiply by 0.01). The cutoffs for HbA_1c stratification were chosen by both inspecting terciles of the HbA_1c distribution among SGLT2i treatment initiators and considering the thresholds currently recommended to define controlled vs uncontrolled hyperglycemia.^{12 (link),13 (link)}

The study was approved by the Isfahan University of Medical Sciences ethics committee (Approval no. IR.MUI.MED.REC.1397.230), and was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all patients. The study protocol was registered at irct.ir as IRCT20171030037093N11 (https://irct.ir/trial/39062).
Ninety two eligible patients were selected using convenience sampling method. Then, these patients were divided into two groups using random allocation software. At the beginning of the study, patients’ demographic and clinical information including sex, age, BMI, waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), comorbidities, duration of T2D, history of drug use (lipid-lowering drugs, hypoglycemic drugs, and antihypertensive drugs), biochemical parameters including urine creatinine (Urine Cr), urine albumin (Urine Alb), UACR, Hemoglobin A1c (HbA1c), fasting plasma glucose (FPG), serum creatinine and glomerular filtration rate (GFR) by MDRD formula, lipid profile including triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and total cholesterol, and liver enzymes including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) were recorded.
For all patients, a routine diabetes treatment was prescribed according to the standard protocol of American Diabetes association (ADA) statement. In addition, 5 mg of linagliptin was administered to patients in the intervention group for 24 weeks while patients in the control group received placebo for 24 weeks.
It should be mentioned that in order to comply with the double-blind condition, linagliptin and placebo which had been already prepared by Alhavi Pharmaceutical Company, located in Tehran, Iran, in the same shape, size, and color. Starch had been used to make placebo tablets. The prepared drugs had been coded, and provided to the researcher. Therefore, the researcher, patients, the information evaluator, and the statistical analyst had no knowledge of the type of the intervention performed in the two groups.
Furthermore, all patients were requested to follow the healthy dietary patterns and proper physical activity in the treatment process to control these factors as much as possible and prevent the disruptive effect of patients’ eating habits and physical activity on the results of the study.
Patients were evaluated in terms of the complications of the medication two weeks after the beginning of the intervention and then every 4 weeks. In addition, patients’ anthropometric, blood pressure, and biochemical factors were assessed 12 weeks and 24 weeks after the intervention. To perform accurate measurements and evaluations, data collection was performed by a single specialist technician, and all biochemical tests were performed only in the Laboratory of Isfahan Endocrine and Metabolism Research Center.