7B.06

Hyphenated mass spectrometry techniques for assessing medication adherence: advantages, challenges, clinical applications and future perspectives

Nonadherence to prescribed pharmacotherapy is an understated public health problem globally and is costing many patients their chance to return to good health and healthcare systems billions. Clinicians need an accurate assessment of adherence to medications to aid the clinical decision-making process in the event of poor patient progress and to maximise the patient health outcomes from the drug therapies prescribed. An overview of indirect and direct methods used to measure medication adherence is presented, highlighting the potential for accurate measuring of drugs in biological samples using hyphenated mass spectrometry (MS) techniques to provide healthcare professionals with a reliable evidence base for clinical decision making. In this review we summarise published applications of hyphenated MS techniques for a diverse range of clinical areas demonstrating the rise in the use of such direct methods for assessing medication adherence. Although liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods using plasma, serum and urine samples are the most popular, in recent years increased attention has been given to liquid chromatography high-resolution mass spectrometry (LC-HRMS) methods and alternative biosample matrices including hair, saliva and blood microsamples. The advantages and challenges of using hyphenated MS techniques to address this healthcare problem are also discussed alongside future perspectives.

Systolic Blood Pressure and Biochemical Assessment of Adherence: A Cross-Sectional Analysis in the Emergency Department

Elevated blood pressure (BP) is common in the emergency department (ED), but the relationship between antihypertensive medication adherence and BP in the ED is unclear. This cross-sectional study tested the hypothesis that higher antihypertensive adherence is associated with lower systolic BP (SBP) in the ED among adults with hypertension who sought ED care at an academic hospital from July 2012 to April 2013. Biochemical assessment of antihypertensive adherence was performed using a mass spectrometry blood assay, and the primary outcome was average ED SBP. Analyses were stratified by number of prescribed antihypertensives (<3, ≥3) and adjusted for age, sex, race, insurance, literacy, numeracy, education, body mass index, and comorbidities. Among 85 patients prescribed ≥3 antihypertensives, mean SBP for adherent patients was 134.4 mm Hg (±26.1 mm Hg), and in adjusted analysis was -20.8 mm Hg (95% confidence interval, -34.2 to -7.4 mm Hg; P=0.003) different from nonadherent patients. Among 176 patients prescribed <3 antihypertensives, mean SBP was 135.5 mm Hg (±20.6 mm Hg) for adherent patients, with no difference by adherence in adjusted analysis (+2.9 mm Hg; 95% confidence interval, -4.7 to 10.5 mm Hg; P=0.45). Antihypertensive nonadherence identified by biochemical assessment was common and associated with higher SBP in the ED among patients who had a primary care provider and health insurance and who were prescribed ≥3 antihypertensives. Biochemical assessment of antihypertensives could help distinguish medication nonadherence from other contributors to elevated BP and identify target populations for intervention.