Cost-Utility Of Liquid Chromatography -Tandem Mass Spectrometry (LC-MS/MS)-Based Urine Analyses To Improve Adherence To Antihypertensive Treatment

Abstract

Objectives: In the UK, over 28% of the population are estimated to suffer from hypertension. A high systolic blood pressure (SBP) increases the risk for cardiovascular disease (CVD). While antihypertensive medications, along with lifestyle changes, are deemed effective in combatting hypertension, adherence to drug treatment may not be optimal. Data from UK patient samples show that discussion of the results from LC-MS/MS-based urine analyses with patients can improve adherence significantly. The objective of this study was to determine whether performing LC-MS/ MS-based urine analyses is cost-effective by improving adherence in hypertensive patients. Methods: Cost-utility analysis was performed from a UK healthcare payer perspective over a lifetime horizon. A Markov model was adapted from an existing published model in a UK setting. Hypertensive patients entered the model event-free, but at risk for cardiovascular events. Effectiveness of urine analysis was modelled by lowering the probability of having an event, as a consequence of lowered SBP by improved adherence to drug treatment, as found in the empirical study. Cost and utilities were derived from literature. The base case cohort consisted of males aged 65. Further analysis varied sex and age of the population. Subgroup analysis concerned those with resistant hypertension, and univariate and probabilistic sensitivity analyses were also performed. Results: The intervention resulted in an incremental health benefit of 0.020 quality-adjusted life-years (QALYs) per patient, and incremental cost was -£867 per patient, i.e. the intervention strategy is dominant compared to care as usual. Sensitivity analyses showed that targeting younger patients (aged 45) or only patients with resistant hypertension would increase cost savings and QALY gains. Conclusions: Using LC-MS/MS-based urine analyses to improve adherence in hypertensive patients is an effective and cost-saving strategy, especially in patients with resistant hypertension, since nonadherence is found to be higher in this population.