The characteristics of the analyzed article
There were 19 articles included in the analysis which was published between the year 2001–2020 (n = 19), nine articles as secondary analysis [17,18,19,20,21,22,23,24,25], one article in pilot study (longitudinal design) , eight articles in original study (cross-sectional design) [27,28,29,30,31,32,33,34]. Except one of the articles published from South Korea , the rest were from the United State (n = 17) [17,18,19,20,21,22,23,24,25,26,27,28, 30,31,32,33,34]. As in study population, except one article paired patients with HF (mostly male) and primary care providers (mostly female), there were 114 patients recruited as research subjects , while the remaining research subjects were received as outpatients (n = 14) [17,18,19, 21,22,23,24,25,26,27, 29, 31,32,33], male (n = 17) mostly [17,18,19, 21,22,23,24,25,26,27,28,29,30,31,32,33,34], number of recruitment cases between 24 and 445 [17,18,19, 21,22,23,24,25,26,27,28,29,30,31,32,33,34], with an average age of 54–71 years [17,18,19, 21,22,23,24,25,26,27,28,29,30,31,32,33,34]. In terms of patients’ HF characteristics, the mean Left Ventricular Ejection Fraction (LVEF) was between 27 and 68% [17, 20,21,22,23,24,25,26,27,28,29,30, 32,33,34]. New York Heart Association (NYHA) Functional Classification (FC) was dominated by I ~ II mostly (n = 9) [17, 18, 20, 21, 27, 29, 31, 33, 34]. In the method of sodium intake estimation, self-reports were majorly used (e.g. diet logs, questionnaires, interviews, checklists, etc.) (n = 7) [18, 19, 26, 29–31, 34], followed by urinary sodium excretion (n = 8) [21,22,23,24,25, 28, 32, 33]. The reports of sodium intake estimation that utilized both urinary sodium excretion and self-reports simultaneously were least (n = 3) [17, 20, 27] (Table 1).
Related factors of compliance behavior towards low-sodium diet
This study identified meaning units through content analysis which were classified into four categories (Table 2). The four categories were: social and economic conditions, patient conditions, disease conditions and therapy conditions. Social and economic conditions contained two subcategories: personal demographics and attribute information. Patient conditions include three subcategories: health, social support, and self-care.
Social and economic conditions
Ten included articles (55.56%) in this study demonstrated the low-sodium dietary compliance was associated with social and economic conditions. Social and economic conditions referred to two categories which were personal demographics and attribute information. Personal demographics subcategorized as age [25, 31], gender [17, 21, 29, 33], race . Whereas attribute information subcategorized as education level , income level , marital status , body mass index [18, 22, 24, 25, 28].
Thirteen included articles (72.22%) in this study showed that low-sodium dietary compliance was associated with patient conditions. Patient conditions contained three subcategories, health, social support, and self-care. Health subcategory consisted of cognitive function [24, 25], diabetes [24, 30], nutrition , mental health [29, 31, 34], physical health . Social support subcategory referred to factors such as the meaningfulness and attitude of the significant others of the patients toward a low-sodium diet , anyone who eat together also followed a low-sodium diet , if there is a chef helps to prepare the food at home . Self-care subcategory, such as patients’ knowledge to low-sodium diet [20, 28], patients controlled their impulsivity of eating high-sodium foods (willpower) , incentive to follow a sodium diet (motivation) [27, 32, 34].
Disease conditions referred to the characteristics of the condition in patients with HF. Two included articles (11.11%) in this study showed that low-sodium dietary compliance was associated with disease conditions. For example: period of suffering from HF , severity of HF .
Therapy conditions referred to treatment related to HF. One included article (5.56%) in this study showed that low-sodium dietary compliance was associated with therapy conditions, such as the medication .
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