ABC | Volume 112, Nº2, February 2019

Original Article Cut-Point for Satisfactory Adherence of the Dietary Sodium Restriction Questionnaire for Patients with Heart Failure Karina Sanches Machado d’Almeida, 1,2,5 Sofia Louise Santin Barilli, 2,3 Gabriela Corrêa Souza, 2,4 Eneida Rejane Rabelo-Silva 1,2,3 Programa de pós-graduação em Cardiologia e Ciências Cardiovasculares da Faculdade de Medicina da Universidade Federal do Rio Grande do Sul, 1 Porto Alegre, RS – Brazil Clínica de Insuficiência Cardíaca do Hospital de Clínicas de Porto Alegre, 2 Porto Alegre, RS – Brazil Programa de pós-graduação da Escola de Enfermagem da Universidade Federal do Rio Grande do Sul, 3 Porto Alegre, RS – Brazil Departamento de Medicina Interna da Faculdade de Medicina da Universidade Federal do Rio Grande do Sul, 4 Porto Alegre, RS – Brazil Curso de Nutrição da Universidade Federal do Pampa, 5 Itaqui, RS – Brazil Mailing Address: Eneida Rejane Rabelo da Silva • Escola de Enfermagem da Universidade Federal do Rio Grande do Sul - Rua São Manoel, 963. Postal Code 90620-110, Rio Branco, Porto Alegre, RS – Brazil E-mail: eneidarabelo@gmail.com, esilva@hcpa.edu.br Manuscript received April 06, 2018, revised manuscript July 21, 2018, accepted August 02, 2018 DOI: 10.5935/abc.20190011 Abstract Background: The low or non-adherence to reduction of sodium intake has been identified as one of the main precipitating factors of heart failure (HF). The Dietary Sodium Restriction Questionnaire (DSRQ) identifies factors that can interfere with adherence to this recommendation. However, there is still no cut-point to define adherence for this questionnaire. Objectives: To identify the cut-point for satisfactory adherence to the Brazilian version of the DSRQ, (the Questionário de Restrição de Sódio na Dieta, QRSD). Methods: Multicenter study. Patients with HF in outpatient treatment (compensated) and those treated in emergency departments due to acute HF (decompensated) were included. For the cut-point definition, the DSRQ scores were compared between groups. A ROC curve was constructed for each subscale to determine the best point of sensitivity and specificity regarding adherence. A 5% significance level was adopted. Results: A total of 206 compensated patients and 225 decompensated were included. Compensated patients exhibited scores that showed higher adhesion in all subscales (all p <0.05). Scores ≥ 40 points of a total of 45 for the subscale of Attitude and Subjective Norm; scores ≤ eight of a total of 20 for Perceived Behavioral Control; and ≤ three of a total of 15 for Dependent Behavior Control were indicative of satisfactory adherence. Conclusions: Based on the evaluation of patients in these two scenarios, it was possible to determine the cut-point for satisfactory adherence to the reduction of sodium in the diet of patients with HF. Countries with similar culture could use this cut-point, as other researchers could also use the results as a reference for further studies. (Arq Bras Cardiol. 2019; 112(2):165-170) Keywords: Heart Failure/physiopathology; Sodium,Dietary; Surveys and Questionnaires; Behavior Control; Decision Making; Muklticenter Study. Introduction Reduction of sodium intake is usually part of the non‑pharmacological treatment for patients with heart failure (HF), since the excessive consumption is associated with fluid retention and congestive situations. 1,2 A poor or non-adherence to this recommendation has been identified among the main precipitating factors of HF decompensation 3-5 and has been linked to the need for hospitalization and worse outcomes. 6,7 To understandwhat factors could potentially interferewith the adherence to the reduction of sodium intake, researchers from the United States of America developed the Dietary Sodium Restriction Questionnaire (DSRQ). 8 This instrument is based on the Planned Behavior Theory and considers three constructs: attitude, subjective norm and perceived behavioral control. Recently, the DSRQ was adapted (transculturally) and validated for the Portuguese language in Brazil, with the name Questionário de Restrição de Sódio na Dieta (QRSD). 9,10 Although the DSRQ has already been the object of other studies, 11-13 there is still no cut-point to define satisfactory adherence for the interviewed patients. Seeking to fill this gap, this study was designed to identify a cut-point for satisfactory adherence to sodium restriction when using the QRSD, both for stable patients on outpatient care, and for decompensated patients. Methods Design and sample This is a case-control study, conducted in two institutions in southern Brazil from March 2010 to October 2014. 165