Non-adherence to heart failure medications predicts clinical outcomes: assessment in a single spot urine sample by liquid chromatography-tandem mass spectrometry (results of a prospective multicentre study)

Aims: \ud Liquid chromatography-mass spectrometry (LC-MS/MS) is an objective new technique to assess non-adherence to medications. We used this method to study the prevalence, predictors and outcomes of non-adherence in patients with heart failure with reduced left ventricular ejection fraction (HFrEF).\ud \ud Methods and results: \ud This study included 1296 patients with HFrEF from BIOSTAT-CHF, a study that aimed to optimise guideline-recommended therapies. Angiotensin-converting enzyme inhibitors (ACEi), angiotensin receptor blockers (ARBs), mineralocorticoid receptor antagonists, β-blockers and loop diuretics were measured in a single spot urine sample at 9 months using LC-MS/MS. The relationship between medication non-adherence and the composite endpoint of all-cause death or heart failure hospitalisation, over a median follow-up of 21 months, was evaluated. Non-adherence to at least one prescribed medication was observed in 45.9% of patients. The strongest predictor of non-adherence was non-adherence to any of the other medication classes (P