Efficacy of a brief multifactorial adherence-based intervention in reducing blood pressure: a randomized clinical trial

Abstract

Alfonso Leiva,1 Antonio Aguiló,2 Marta Fajó-Pascual,3 Lucia Moreno,4 Ma Carmen Martín,5 Elena Marina  Garcia,6 Rosa Elena Duro,7 Francisca Serra,8 Pilar Dagosto,9 Ana Aurelia Iglesias-Iglesias,10 Rosa Maria Company,11 Aina Yañez,12 Joan Llobera13 On behalf of The Adherence Group 1Primary Care Research Unit of Mallorca, Baleares Health Services-IbSalut, Mallorca, 2Research Group on Evidence, Lifestyles and Health, Universitat Illes Balears, Palma, 3Faculty of Health and Sport Sciences, University of Zaragoza, Huesca, 4Son Cladera Health Centre, Baleares Health Services-IbSalut, Mallorca, 5Actur Sur Health Centre, Aragon Health Services-Salud, Aragón, Zaragoza, 6Coll D’en Rabassa Health Centre, Baleares Health Services-IbSalut, Mallorca, 7San Agustín Health Centre, Baleares Health Services-IbSalut, Mallorca, 8Santa María Health Centre, Baleares Health Services-IbSalut, Mallorca, 9Sineu Health Centre, Baleares Health Services-IbSalut, Mallorca, 10Santa Ponça Health Centre, Baleares Health Services-IbSalut, Mallorca, 11Department of Pharmacy, Manacor Hospital-Llevant Sector, Baleares Health Services-IbSalut, Mallorca 12Montuiri Health Centre, Baleares Health Services-IbSalut, Mallorca, 13Fundació d’Investigació Sanitaria Illes Balears (FISIB), Son Espases Hospital, Baleares Health Services-IbSalut, Mallorca, SpainBackground: Lowering blood pressure (BP) by antihypertensive (AHT) drugs reduces the risks of cardiovascular events, stroke, and total mortality. However, poor adherence to AHT medications reduces their effectiveness and increases the risk of adverse events.Objective: To evaluate the effectiveness of a multifactorial adherence-based intervention in a primary care setting in lowering BP.Methods/design: Multicenter parallel randomized controlled trial. Thirty two nurses in 28 primary care centers of three Spanish regions. Patients aged 18–80 years, taking AHT drugs with uncontrolled BP (n=221) were randomized to a control group (usual care) or a multifactorial adherence-based intervention including nurse-led motivational interviews, pill reminders, family support, BP self-recording, and simplification of the dosing regimen by a pharmacist.Main outcome measures: The primary outcome was 12-month blinded measure of systolic BP (mean of three measurements). The secondary outcomes were 12-month diastolic BP and proportion of patients with adequately controlled BP.Results: One hundred and fourteen patients were allocated to the intervention group and 109 to the control group. At 12 months, 212 (89%) participants completed the study. The systolic BP in the intervention group was 151.3 versus 153.7 in the control group (P=0.294). The diastolic BP did not differ between groups (83.4 versus 83.6). Of the patients in the control group, 9.2% achieved BP control versus a 15.8% in the intervention group. The relative risk for achieving BP control was 1.72 (95% confidence interval: 0.83–3.56).Conclusion: A multifactorial intervention based on improving adherence in patients with uncontrolled hypertension failed to find evidence of effectiveness in lowering systolic BP.Trial registration: ISRCTN21229328.Keywords: hypertension, medication adherence, blood pressure, intervention studies