Systolic Blood Pressure and Biochemical Assessment of Adherence

Abstract

Elevated blood pressure is common in the emergency department, but the relationship between antihypertensive medication adherence and blood pressure in the emergency department is unclear. This cross sectional study tested the hypothesis that higher antihypertensive adherence is associated with lower systolic blood pressure in the emergency department among adults with hypertension who sought emergency department care at an academic hospital from July 2012-April 2013. Biochemical assessment of antihypertensive adherence was performed using a mass spectrometry blood assay, and the primary outcome was average emergency department systolic blood pressure. Analyses were stratified by number of prescribed antihypertensives (<3, ≥3) and adjusted for age, sex, race, insurance, literacy, numeracy, education, body mass index, and co-morbidities. Among 85 patients prescribed ≥3 antihypertensives, mean systolic blood pressure for adherent patients was 134.4 mm Hg (+/− 26.1 mm Hg), and in adjusted analysis was −20.8 mmHg (95% CI −34.2 to −7.4 mm Hg, p=0.003) different from non-adherent 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% CI −4.7 to 10.5 mm Hg, p=0.45). Antihypertensive non-adherence identified by biochemical assessment was common and associated with higher systolic blood pressure in the emergency department 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 non-adherence from other contributors to elevated blood pressure and identify target populations for intervention.

Characteristics and treatment of African-American and European-American patients with resistant hypertension identified using the electronic health record in an academic health centre: a case−control study

“… 79 We recently reported a rigorous adherence rate of 58.8%, among hypertensive patients in an emergency department prescribed three or more antihypertensive medications based on the detection of drugs in the plasma. 14 Second, we used outpatient office BP measurements to define resistant hypertension in the EHR, but ambulatory measurements would be necessary to distinguish between apparent resistant and true resistant hypertension. 7 Lastly, it is possible that offsite prescriptions or discontinuations of antihypertensive medications were not captured in the EHR; we overcame this potential limitation by requiring repeated documentation of a medication over more than a month in the study algorithms.…”

“…Studies assessing medication adherence using blood and urine levels to measure antihypertensive medication intake estimate the rate of non-adherence, including partial and complete non-adherence, to be approximately 50% in resistant patients with hypertension and 25% in patients with hypertension with uncontrolled BP. 14–16 These conditions may contribute to uncontrolled BP in some but not all patients with resistant hypertension. The molecular mechanisms underlying resistant hypertension in the remaining population remain unknown.…”

Medication adherence during laboratory workup for primary aldosteronism: pilot study

“…Qualitative drug screening based on LOQ thresholds may thus easily generate false positive results when drugs are slowly cleared from plasma and can be detected still days after discontinuation. 5 , 10 , 25 , 26 , 29 , 30 Using indexed plasma drug concentrations and expected C min as a threshold for same-day drug intake, we additionally revealed up to four nonadherent patients compared with only qualitative plasma drug screening. Drug concentrations in our study were generally around the expected C max or within the therapeutic range, that is, between C max and C min .…”

Assessment of Patient Medication Adherence, Medical Record Accuracy, and Medication Blood Concentrations for Prescription and Over-the-Counter Medications

“…A convenience cohort of patients with hypertension who were treated by a VUMC primary care professional and who sought medical care in the VUMC adult emergency department (ED) between July 1, 2012, and April 25, 2013, was used as the ED care cohort, and these patients were approached for enrollment. A full description of the inclusion criteria and the patient cohort is available elsewhere 13 ; in brief, patients prescribed at least 1 of 14 antihypertensive medications for hypertension and a functioning peripheral intravenous line were approached for consent. Of the 300 individuals who provided written informed consent to participate, 296 had serum samples available for secondary exploratory analyses.…”