Illness perception and treatment adherence in patients with chronic heart failure and sideropenic anemia

Objective: The primary aim of this study was to examine whether the perception of the patient’s disease and adherence to treatment process influence treatment outcomes of heart failure. The secondary aim was to analyze whether there were differences in perception and adherence in patients with heart failure in relation to anemia. Method. A cross-sectional study was carried out in 2015. One group consisted of 100 patients with heart failure and sideropenic anemia. The other group consisted of 100 patients without anemia. The standardized questionnaire was used to collect demographic data, the Brief Illness Perception Questionnaire to measure the patients’ perception of the disease and modified Clinician rating scale to assess patient’ s adherence. Results: The majority of respondents in the first group were women 63%, while in the second group there were 58% male and 42% female respondents. Respondents from the first group had statistically significantly lower adherence compared to respondents from the second group (χ2 = 23.28; p=0.05). A significant difference was found between the groups of subjects in comparison to the perception of disease control (χ2=18.03; p=0.05). Conclusion: The illness perception and treatment adherence have a significant impact on treatment outcomes of heart failure. Comorbidities, such as anemia, contribute to the patients’ perception of their disease and influence their adherence. Кey words: heart failure, sideropenic anemia, illness perception, adherence doi:10.5937/opmed1902029D


Introduction
In the cardiovascular continuum chronic heart failure (HF) represents the final stage of all cardiovascular diseases, regardless of whether it is ischemic, hypertensive, valvular or immuno-infected.Hospitalization rates, post-discharge mortality and readmission rates are still very high despite the improved treatment options; ultimately leading to high consumption of healthcare resources in developed as well as in developing countries 1 .
Previous studies found that health -related quality of life, as a treatment outcome, is deteriorated in heart failure 2 , particularly when associated with comorbidities 3,4,5 .Anemia is very common in heart failure, especially in hospitalized patients, females, elder people and those with renal insufficiency.An erythropoietin inhibition occurs on two levels: the kidneys and the bone marrow have the biggest role in the onset of anemia in heart failure.The damaged myocardium in heart failure produces increased amounts of cytokine tumor necrosis factoralfa, which inhibits the effect of erythropoietin on the progenitor cell of the red blood cell, due to which it prevents the release of iron from the reticuloendothelial system and reduces the hemoglobin synthesis 6 .Anemia may lead to the worsening of heart failure and decline of health-related quality of life of patients suffering from heart failure 4 .
The perception of disease represents a patient`s cognitive belief about their disease, and it signifies important determinant of behavior and results in numerous outcomes that are important for the patient's cooperation and functional recovery.Illness perception is also important for clinician in order to understand what kind of beliefs a person has (whether ethical, social or religious), how disease affects patients' everyday life (a relationship with family, friends), or how much a person is able to control the disease (does the disease control a person or a person controls the disease) 7 .Identification of patients' beliefs and behavior plays an important role in the treatment and education of patients with HR 8 .However, data on the association of illness perception and treatment outcomes in patients with heart failure and associated anemia are lacking.
The primary aim of this study was to examine whether the perception of the patient's disease and adherence in the treatment process influences treatment outcomes of heart failure.The secondary aim was to analyze whether there are differences in perception and adherence in patients with heart failure in relation accompanying anemia.

Study participants
A cross-sectional study was carried out at the Department of Cardiology, Clinical Center Banja Luka, Bosnia and Herzegovina, from April to September 2015.Eligible patients were men and women, 18 years of age or older, outpatients, with symptomatic chronic heart failure and New York Heart Association (NYHA) functional classes III and IV at time of enrolment.Another enrolment criterion was left ventricular ejection fraction (LVEF] ≤45% measured by echocardiography.The diagnosis of heart failure was made by experienced cardiologists.The patients were further divided into two groups.One group consisted of 100 consecutive patients with heart failure and associated anemia, and the other group of 100 consecutive patients with heart failure but without anemia.Patients were excluded if they were unable to complete the questionnaires, had undergone intervention within the last 6 months, experience symptoms for which hospitalization was considered necessary and had chronic liver disease or pericardial disease.

Instruments
The standardized questionnaire was used to collect sociodemographic data about the study participants.
The Brief Illness Perception Questionnaire (IPQ) measured the patients' perception of the disease 9 , included 8 items, evaluating the perception on a 0-10 response scale.Five items analyzed cognitive aspects, such as identity, personal control, treatment control, consequences, and timeline.Questions numbered six and seven focused on concerns and emotions, and question eight on illness comprehensibility.Separate item was an open-ended question on the three most important causal factors of their illness.The higher the score, the more person felt endangered by the illness.
To evaluate treatment adherence, the researchers asked all patients to complete a Clinical rating scale (CRS).The scale encompassed 7 questions with dichotomous answers (YES or NO) and one question on how often the patient did not take his medications.According to the overall score, the adherence was categorized as low (<5), intermediate (5-6)  and high (7).Higher numbers represent greater adherence 10,11 .
Treatment outcomes assessed, included the Likert scale for dyspnea and fatigue, analysis of number and length of hospitalization, the presence of peripheral edema, 24-hour measurement of blood pressure, levels of CRP, sedimentation rate (ESR), hemoglobin, hematocrit, iron, TIBC, and ferritin values.

Statistical analysis
Statistical analysis was performed using the v22 SPSS package.Numbers and percentage for categorical variables were used to describe clinical outcomes, treatment adherence, and illness perception.The linear correlation between the variables was analyzed with Pearson correlation coefficient.Statistically significant difference was evaluated by application of χ2 square test.P-value level <0.05 was considered significant.

Ethical Considerations
All participants gave informed consent.Data are presented in a manner that conceals the participants` identities.

Discussion
The current study found a relationship between treatment outcomes and treatment adherence in addition to illness perception among patients with heart failure.The study participants with associated anemia felt more endangered by their disease and were less adherent to the treatment compared to individuals without anemia.Our findings corroborate the results of previous studies 3,5,12 .
Although the difference between the values of diastolic and systolic arterial pressure individually was not found between the participants in regards to anemia, anemic patients were more often hypertensive compared to non-anemic.Joseph et al. detected higher blood pressure values in HR patients with anemia 13 , while recent Korean study showed no association between anemia and hypertension 14 when adjusted to body mass index and waist circumference.Correlation between how patients perceive their illness or adhere to medication and hypertension was not statistically significant.However, the results may have been influenced by other risk factors that were not analyzed in the present study.
In line with previous research, anemic patients experienced fatigue, dyspnea, and edema more frequently compared to participants in G2, and it added to the general symptomatic status of the individuals 15 .Several groups of medications used to treat HR, angiotensin-converting inhibitors and betablockers may have increased the risk of anemia by inhibiting the hematopoietic activity or decreasing hemoglobin level.Anemia further decreases oxygen delivery and worsens dyspnea and fatigue 16 .Patients who considered dyspnea alarming and had edema, perceived their illness worse and were less adherent to the recommended treatment.
Anemic patients reported a strong impact of illness on their lives and poorly controlled, incurable disease.Earlier research showed that stronger illness perception leads to better control over disease, and hence, more effective strategies for overcoming the disease or ability to cope withchallenges posed by the chronic disease.It also detected that people with higher severity of the disease also express greater concern about the disease and consider that the disease has a major impact on their life 17 .The length of hospitalizations and the duration of disease were in negative correlation with a perception of the disease and treatment adherence in the current study, which could be explained by the fact that people are not passive objects affected by the disease, but that beliefs about the disease affect their perception 18 .The everity of the disease is significantly related to the perception of chronic diseases and the negative impact on the disease on the emotional state 19 .Morgan et al. found that emotions and mood are integral aspects of illness perception 20 .Disease understanding was the only domain of illness perception in correlation with patients' adherence.By exploring maladaptive illness perceptions among the patients with HR and anemia, patients' wellbeing, treatment outcomes and quality of life could be influenced and improved 12 .
Participants in group one had significantly lower adherence compared to participants from group two.Inadequate use of medicines by patients with cardiovascular disease is a common occurrance in physicians` daily practice 21 .Appropri- ate intervention, such as home-based, high-intensity interval training or multimodal approaches with interactive feedback could improve the adherence to pharmacological therapy and accompanying lifestyle recommendations can be improved by means of appropriate interventions [21][22][23][24] .Exploring patients' views, ideas, and expectations, or introducing the discussion between health care provider and patient during the medical encounter which is not purely medical, has a positive impact on illness perception and helps patients develop an identity and personal control over the treatment process 25 .
Study participants with anemia had higher CRP levels compared to the participants from group 2. The lower the CRP levels, the higher the adherence and illness perception was more positive.Higher levels of CRP are common finding among individuals with more severe heart failure, increasing the risk of mortality and morbidity.The majority of epidemiological studies showed a significant correlation between increased CRP and atherosclerosis, and the risk of repeated cardiovascular events in patients with chronic heart failure 26 .Data on the impact of sideropenic anemia treatment on CRP values in patients with heart failure are limited.

Table 4 .
The relationship between the illness perception and the treatment adherence Табела 4. Повезаност перцепције болести и сарадљивости