An Innovative Chemical Adherence Test Demonstrates Very High Rates of Nonadherence to Oral Cardio-Metabolic Medications

Abstract

Chronic kidney disease (CKD) is one of the leading causes of death worldwide. About 13% of the world’s population are living with CKD; and over the last 20 years, there has been over a 40% increase in mortality rates due to CKD.1,2 Compared to patients without CKD, CKD stages G3a to G4 (estimated glomerular filtration rate 15–60 ml/min per 1.73 m2) is associated with a 2 to 3 fold increase in risk of cardiovascular disease mortality.3 It is estimated that about 17% to 74% of patients with CKD are nonadherent to their medications.4 Improvement in adherence has been identified as a key strategy to enhance cardiovascular outcomes.5 However, the diagnosis of nonadherence, until recently, was difficult due to the lack of objective tools in busy clinics because some subjective methods have been found to be unreliable.6 Chemical adherence testing (CAT) is a novel, objective, robust and clinically reliable test that uses liquid-chromatography tandem mass spectrometry to assess adherence to medications. A random spot urine or blood sample is screened to determine the presence or absence of 70 of the most common cardio-metabolic medications (Supplementary Table S1) (including antihypertensives, lipid lowering medications, and glucose lowering drugs).7 There are guidelines available to help implement the use of the test and address common questions about the clinical use of the test.7 Currently, CAT is being used in routine care in some specialist hypertension clinics across Europe and has been recommended by the European Society of Cardiology and the European Society of Hypertension as the method to be used to measure adherence in patients with suspected resistant hypertension.8 The use of CAT is limited outside of hypertension and to the best of our knowledge there has been no publication that has used CAT to diagnose medication nonadherence in renal patients. The aim of this study was therefore to demonstrate and highlight the usefulness of CAT to determine the prevalence of nonadherence to cardio-metabolic medications in patients attending routine renal clinics.</p