title: A practical approach for measurement of antihypertensive medication adherence in patients with resistant hypertension.
abstract: Confirmation of medication adherence is a challenge in clinical practice and essential for the accurate diagnosis of resistant hypertension. Although it is well established that drug adherence is critical for controlling blood pressure, there are still difficulties applying a simple, inexpensive, and reliable assessment of adherence in the clinical setting. We aimed to test a simple method to assess adherence in resistant hypertensive (RH) patients. A pilot study with normotensives or mild/moderate hypertensive subjects was performed to provide a fluorescence cutoff point for adherence. After that, 21 patients referred to the Resistant Hypertension Clinic had triamterene prescribed and were monitored for a 30-day period. We conducted two unannounced randomly selected home visits for urine collection to test drug intake that day. Office, home and 24-hour ambulatory blood pressure, biochemical data, and the 8-item Morisky Medication Adherence Scale (MMAS-8) were systematically acquired. According to adherence indicated by urine fluorescence, subjects were divided into adherent and nonadherent groups. We found 57% of nonadherence. No differences were found between groups regarding baseline characteristics or prescribed medications; Kappa's test showed concordance between adherence through MMAS-8 items and fluorescence (kappa = 0.61; 95% confidence interval: 0.28-0.94; P = .005). Nonadherent patients had higher office (81 ± 11 vs. 73 ± 6 mm Hg, P = .03), 24-hour ambulatory blood pressure monitoring (75 ± 9 vs. 66 ± 7 mm Hg, P = .01), and home blood pressure measurement (77 ± 9 vs. 67 ± 8 mm Hg, P = .01) diastolic blood pressure than their counterparts. Nonadherence to antihypertensive therapy is high in patients with RH, even when assessed in clinics specialized in this condition. Fluorometry to detect a drug in the urine of RH patients is safe, easy, and reliable method to assess adherence.
authors.affiliation: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Nathália Batista
authors.initials: NB
authors.lastname: Corrêa
authors.affiliation: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: de Faria
authors.affiliation: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Alessandra M V
authors.initials: AM
authors.lastname: Ritter
authors.affiliation: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Andrea Rodrigues
authors.initials: AR
authors.lastname: Sabbatini
authors.affiliation: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Aurélio
authors.initials: A
authors.lastname: Almeida
authors.affiliation: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Veridiana
authors.initials: V
authors.lastname: Brunelli
authors.affiliation: Vascular Biology and Hypertension Program, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Calhoun
authors.affiliation: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil.
authors.forename: Heitor
authors.initials: H
authors.lastname: Moreno
authors.affiliation: Cardiovascular Pharmacology Laboratory, Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil. Electronic address: rodrigo_modolo@yahoo.com.br.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Modolo
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000627:therapeutic use* / Q000652:urine; D001795:Blood Pressure Determination; D018660:Blood Pressure Monitoring, Ambulatory; D003329:Coronary Vasospasm / Q000188:drug therapy* / Q000523:psychology* / Q000652:urine; D004232:Diuretics / Q000008:administration & dosage / Q000627:therapeutic use* / Q000652:urine; D005240:Feasibility Studies; D005260:Female; D005470:Fluorometry; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000523:psychology* / Q000652:urine; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D014223:Triamterene / Q000008:administration & dosage / Q000627:therapeutic use / Q000652:urine
chemical_list: D000959:Antihypertensive Agents; D004232:Diuretics; D014223:Triamterene
keywords: Pharmacological adherence; refractory hypertension; triamterene; urine fluorescence