Biochemical urine analysis of atorvastatin and rosuvastatin by LC-MS: a pilot study of an objective method to assess non-adherence

Non-adherence to statins represents a contributing factor for poor attainment of low-density lipoprotein cholesterol treatment goals in secondary prevention of coronary artery disease (CAD). We aimed to establish urine analysis by liquid chromatography/mass spectrometry (LC-MS) as a method for objective measurement of non-adherence to high-potency statins. Additionally, we sought to apply the method to a population of ambulatory CAD patients at a German heart center in a cross-sectional pilot study. Volunteers provided urine samples one, two, three, and seven days after intake of a single dose of atorvastatin and/or rosuvastatin. Additionally, urine samples from ambulatory CAD patients on prescription of atorvastatin or rosuvastatin were obtained. All urine samples were analyzed by LC-MS for concentrations of atorvastatin or rosuvastatin. Lower limits of detection were determined on spiked urine samples to define cut-off values (COVs) for the detection of statins (atorvastatin 1.40 ng/mL, rosuvastatin 1.00 ng/mL). Non-adherence was defined as a measurement of the respective statin below the COV. On day one, in volunteers’ (n = 16, 37.3 ± 6 years, 81.3% male) urine samples, concentrations were above COV in 92.3% (atorvastatin, n = 13) and 90% (rosuvastatin, n = 10). After seven days, atorvastatin could not be detected in all 13 volunteers (100%) and rosuvastatin in nine of ten volunteers (90.0%), LC-MS analysis of urine is a feasible method for direct testing of adherence to high-potency statins within a one-week time-window. In the investigated population of ambulatory patients with CAD, non-adherence to statins was found in a considerably low range. ClinicalTrials.gov ID NCT05814692, first registered 20,230,403.