Health Literacy and Relation to Adherence to Pharmacologic Treatment of Patients in Hemodialysis

— Objective: to analyze the relationship between health literacy and adherence to treatment of dialysis patients. Method: cross-sectional study with 424 end-stage renal disease patients on conventional HD in the West and Middle West of Santa Catarina. The SALPHA questionnaire was used to analyze health literacy and the Brief Medication Questionnaire was used for treatment adherence. Minimental was used to analyze cognition. Results: the mean age was 57.3±15.8 years, 53.3% men, 71.4% with low education level, 10.1% have had a kidney transplant, 5.0% reported having already taken an extra dose of medication, 4.0% said they had missed doses and 22.6% admitted failure of days or prescribed doses. Literacy was inadequate for 67%, 49.1% were considered to have cognitive impairment, 55.2% are adhered to treatment. Low adherence to treatment was related to inadequate literacy (p<0.01), literacy and cognition showed a positive correlation (r=0.5; p<0.00), those who reported taking extra dose of the medication were less adherent (p<0.03), as well as those who omitted medication at some point (p<0.02). Conclusion: Inadequate literacy was related to low adherence to treatment, and also to cognitive deficit, low education, and old age.


INTRODUCTION
Patients with Chronic Kidney Disease (CKD) on hemodialysis need to face a complex treatment, which involves changes in lifestyle, dietary adjustments, use of continuous medication and attendance at dialysis sessions 1 . For the treatment to be successful, it is essential that the patient understands the information passed on by the multidisciplinary team and has adequate adherence to the treatment².
To have sufficient understanding of the disease and treatment, it is desirable that the patient has an adequate level of health literacy (HL), which refers to the individual's cognitive and social capacity to obtain, understand and use basic health information for a proper decision-making about your own health³.
HL is defined by the World Health Organization (WHO) as a social determinant of health ⁴and its relevance concerns the possibility of the patient to identify risks to their health, their family and community and have the necessary knowledge to seek help from a professional, as well as assimilate the prescribed care and apply them in their daily lives⁵.
As well as literacy, adherence to medication treatment is also fundamental for the success of therapy, and the high number of daily medications favors nonadherence 6 , which contributes to the increase in mortality associated with the disease. Treatment adherence is directly related to the parameters of disease control and care, more specifically in relation to organizational access and bonding indicators⁷.
During the hemodialysis session, participants responded to four instruments. The Brief Medication Questionnaire (BMQ) for analyzing adherence to medication treatment; the Mini Mental State Examination (MMSE) for cognitive screening; the Short Assessment of Health Literacy for Portuguese-speaking Adults (SAHLPA) to analyze health literacy and a questionnaire to collect socio-demographic and health status data.
Data were analyzed using the SPSS program, using the Shapiro Wilk normality test. The association of categorical data was performed using the chi square and numerical data using the Student t test. When nonparametric data were used, Mann Whitney of independent samples was used. Pearson was used for correlation analysis and 95% confidence was adopted.

III. RESULTS
A total of 424 patients participated in the study (88.1% of the total people on hemodialysis considering the three regions), 39 were excluded for not attending dialysis on the day of data collection, whether due to travel, hospitalization or absence without justification. The mean age was 57.3±15.8 years. Dialysis time had a median of 26 months (interquartile range 11-60), mean of 44.06 months, minimum one month and maximum 288 months. Table 1 shows the profile of the interviewees, their self-reported health habits, medication profile and treatment adherence. Regarding literacy, the mean in the Salpha questionnaire was 11.8±4.3 points, 33% were considered as having adequate literacy and 67% inadequate. Salpha and MEEN values showed a positive correlation (r=0.5; p<0.00). Table 2 shows the relationship between literacy and the characteristics of patients on hemodialysis. Those who reported taking an extra dose of medication were less adherent (p<0.03), as well as those who reported that they had already missed medication at some point (p<0.02). Other adherence characteristics in relation to hemodialysis patient characteristics are described in Table 3.  Table 4 shows literacy and treatment adherence in relation to age, Salpha value and dialysis time.

IV. DISCUSSION
Health literacy was considered inadequate for most participants, which was also verified in other studies 8,9 . In the united kingdom, a survey with 6,842 patients with kidney disease also found inadequate HL 11 . This theme has brought challenges to health professionals due to the need for adjustments in health strategies for effective care 11 .
Analyzing adherence, in this study more than half of the interviewees were considered non-adherent, similar studies that evaluated patients undergoing hemodialysis also showed that most of them had low adherence to treatment 12,13 .
HL was positively correlated with treatment adherence, demonstrating that patients with low adherence also had low ls. In a literature review on the association of sl and adherence to drug treatment 14 , other studies showed a positive relationship between the association of sl and adherence to drug treatment, which is currently also being verified worldwide 15,16,17 .
Treatment adherence is a very complex situation and ckd has several impacts on the lives of individuals and their families, especially in the hemodialysis stage where the need for a transformation in the individual and family lifestyle occurs 18,19 .
It was evident that sl and treatment adherence were related to the presence of cognitive deficit and older age. The relationship with age has already been verified in other studies, as years of education and duration of hemodialysis suggest that older people, with less education and longer duration of hemodialysis had more cognitive impairment 20 . Low educational level contributes to the individual having difficulty in understanding the disease and its clinical picture as complications and associated comorbidities 15,21 .
Marital status was also related to low HL and older age. The fact of having a partner was also found in other studies and was probably related to the factor of advanced age and because it represents a source of emotional support 22 . Family support was verified as a role of protection and socialization of its members, in addition to serving as support in coping with the difficulties arising from the chronic disease and its treatment 23 .
The therapeutic regimen and the amount of medication that patients use were not identified as a difficulty in non-adherence. In a literature review, they concluded that, although there is little evidence, treatment carried out in a structured manner can contribute to improving adherence to treatment of individuals on hemodialysis 24 .
Smokers or former smokers and those who have never had a transplant also had worse results in SL, it is noteworthy that inadequate SL can affect health, so that it reduces their self-management capacity for care 25 , in the same way that the lack of knowledge and skills related to health can be considered as a barrier to the adoption of healthy behaviors and in the prevention or management of acute and chronic diseases 26 .
In this research, the dialysis time of those who adhered to the treatment was longer, but it was not statistically significant. The aspects that motivate treatment adherence include living with the hemodialysis machine, performing laboratory tests, faith and the presence of social support, mitigation of complications and adverse events, requiring interaction between the team and the patient with the purpose of understanding the phenomena that lead to the failure of this process and in the development of educational strategies in order to make individuals aware of the importance of adherence to treatment and possible improvement in quality of life 27 .
The analysis of the HL of patients with CKD can be a tool for situational diagnosis and intervention in the way health professionals work in the management and care of hemodialysis patients, as well as knowing in detail the profile of patients and the difficulties encountered in the its treatment can contribute to the construction of actions that involve their adherence. It ratifies the importance of considering the family context as a supportive source and, mainly, as a factor to be worked on, being necessary to include the family in the teachings and information of the treatment, as a determining factor for the success in the adherence to the treatment.

V. CONCLUSION
Inadequate literacy was found in most of the study population and was correlated with low adherence to treatment, this relationship was accompanied by cognitive deficit, low education, smoking, high age and not having undergone a kidney transplant before.
The complexity of the factors involved in the treatment of chronic kidney disease patients, and the patients' difficulties in adapting to imposed health habits, must be known to support the planning of actions, highlighting the need for a multidisciplinary approach and the importance of education in health, not in a simplified and isolated way, but with different analyzes and approaches.
Understanding and accepting the importance of dialysis treatment is fundamental, and should enable patients to have their autonomy and active participation in the quest to overcome difficulties.