Cardiovascular diseases (CVDs) cause 17.9 million deaths occurred in developing nations (WHO, 2021). In Sub-Saharan African (SSA) countries, poor access to high-quality and inaccessible healthcare contributes to an increase in CVD morbidity and death (Mensah et al., 2015; Meyer et al., 2017; Schultz et al., 2018; Rosengren et al., 2019). The prevalence of CVD in Ethiopia was 5,534 per 100,000 people (Ali et al., 2020).

Globally, heart failure (HF) constitutes a significant medical and economic challenge (Lesyuk et al., 2018). It results from changes in cardiac structure or function that impair the ability of the ventricle to fill with or eject blood (Parker et al., 2020). The incidence and prevalence of HF are increasing; approximately 6.5 million Americans currently have HF, with 1,000,000 new cases diagnosed each year and annual expenditures exceeding 30 billion US dollars (Benjamin et al., 2018). Based on the phenotypes of the disease, HF can be classified as HF with reduced ejection fraction (EF) (HFrEF) and HF with preserved EF (HFpEF) (Mann et al., 2018).

Managing HF remains challenging due to co-existing co-morbidities (Chiatti et al., 2012). In addition, prescribing a higher number of medications for HF patients results in non-adherence to medication and more frequent hospital stays (Page et al., 2016). To achieve favorable clinical outcomes, HF guidelines emphasize the paramount importance of adhering to prescribed treatment regimens (Riegel et al., 2011; Ponikowski et al., 2016). Maximizing treatment results depends critically on adherence to HF medications (Pallangyo et al., 2020).

Studies conducted in various countries indicated that HF patients adhering to their medication experienced fewer emergency department visits, improved clinical survival, fewer HF exacerbations, and lower healthcare costs (Hope et al., 2004; Murray et al., 2009; Wu et al., 2009). However, medication non-adherence was associated with increased hospitalization (Knafl and Riegel, 2014a; Aggarwal et al., 2015), worsening symptoms, disease progression, an overall increase in healthcare costs (Aggarwal et al., 2015), and frequent emergency department visits (Davis et al., 2014). Heart failure medication adherence often falls below optimal levels in global investigations using various adherence evaluation methods (Fitzgerald et al., 2011; Lee et al., 2015; Shah et al., 2015; Amininasab et al., 2018; Fernandez-Lazaro et al., 2019; Rehman et al., 2019; Pallangyo et al., 2020).

Patient satisfaction with prescriptions or services influences treatment outcomes, the duration of pharmacological care, optimal service utilization, clinical compliance, and treatment plan adherence (Langebeek et al., 2014).

Patients satisfied with their treatment adhere more to prescribed therapeutic regimens, take an active role in their self-care, and improve their quality of life compared to those dissatisfied with their therapy (Asadi-Lari et al., 2003; Liberato et al., 2016). Individuals treated satisfactorily with services are more likely to remain members of the healthcare facility and adhere to prescribed medication regimens (Holsclaw et al., 2005). Medication non-adherence in HF patients ranged from 18% (Simpson et al., 2021) to 92% (Chang et al., 2018). While the rate of treatment satisfaction among HF patients was 4.2 mean score out of 5 best scores (Bjertnaes et al., 2012). However, no study has assessed treatment adherence and patient satisfaction among HF patients at DBCSH, Ethiopia. Hence, this study aims to evaluate treatment satisfaction and medication adherence and their predictors, which influence treatment outcomes in HF care.

The study revealed that a treatment satisfaction rate of 67.6% and a medication adherence rate of 60.9% among HF patients.

In medical studies, knowing how satisfied patients are with their treatment is essential to understanding their perspective on care. It is also shown that improving clinical outcomes is connected to increasing patient satisfaction with their care (Al-Jabi et al., 2015).

In this study, most participants were aged 30–59, with an average age of 53.4 years. This was lower than a study in Brazil (average age 60.2, range 28–87) (), but similar to a study in Nigeria (average age 52, range 32–83) (Iloh and Amadi, 2017). But, the study conducted in Greek reported that 74% of participants found in the age range of 18–59 years (Geitona et al., 2008). Age among HF patients was linked to both treatment satisfaction and medication adherence.

More than two-thirds of participants had a co-morbid illness, a finding similar to a Palestinian study (63.2%) (Al-Jabi et al., 2015). Almost three-fourths of the study subjects had received treatment for 4 years or less, in contrast to research in Palestine (Al-Jabi et al., 2015), where the majority had been treated for more than 4 years (69.7%). The variations could be differences in the study participants’ clinical characteristics.

In the current study, participants had an overall treatment satisfaction score was 67.6%. This finding was similar with a study done in Brazil (69.2%) (). However, this result was lower to studies conducted among cancer patients in Greece (85.6%) (Pini et al., 2014), Tikur Anbessa Specialized Hospital, Addis Ababa, Ethiopia (80.81) (Demoz et al., 2019), Nigeria (78.6%) (Iloh and Amadi, 2017), Greek (more than 80%) (Geitona et al., 2008) but higher than studies from Australia (nearly 65% fully satisfied only) (Candlish et al., 1998) and Addis Ababa, Ethiopia (Seid et al., 2020). These differences may be variations in the definition of treatment satisfaction between studies. Patient satisfaction with therapy is the most reliable indicator of continued medication use, impacting the effectiveness and efficiency of medical care (Zyoud et al., 2013; Iloh and Amadi, 2017). So, satisfaction with medication constitutes a quality indicator that can be used for improving healthcare of chronic patients like HF. The findings imply that barriers to treatment satisfaction of HF patients must be addressed.

The satisfaction scores of the study participants regarding medication side effects were relatively low (10.33%) compared to other domains. This result contrasts with a study in Addis Ababa, Ethiopia (79.3%) (Seid et al., 2020), a study in Palestine (86.0%) (Hope et al., 2004), Brazil (93.5%) (), . The discrepancy may be attributed to differences in the study setting, the number of comorbidities the study participant has, number and types of medication study participants take, severity of illness or the side effect items are being measured incorrectly. The Addis Ababa study by Seid et al. was conducted at a tertiary hospital, where patients might have multiple comorbidities and take multiple drugs, potentially leading to more drug side effects among participants. In addition, it is possible that the patients who participated in this study have different understanding of side effects, different perception of side effects, different perception of the severity of side effects, and different interpretation of the SATMED-Q questions.

The global treatment satisfaction domain score was 72.6% in the current study compared to other dimensions. This result was consistent with a study conducted in Palestine (72.1%) (Al-Jabi et al., 2015), but this finding was greater than a study done in Brazil (69.2%) (). The score in the medical care domain was 81%. This finding was higher than a study done in Estonia (68%) (Polluste et al., 2000). A possible reason for this variation could be the treatment satisfaction assessment tools used.

The occurrence of comorbidity, individuals with a diploma or higher educational level, and those with no salt reduction showed a statistically significant relationship with treatment satisfaction. However, other clinical and socio-demographic characteristics did not exhibit a statistically significant relationship with treatment satisfaction. Additionally, our result was inconsistent with studies reported from China (Fang et al., 2019) and Saudi Arabia (Ammo et al., 2014). Primary factors associated with low satisfaction with healthcare services include waiting time, extensive administrative procedures, appointments, and the attitudes of medical personnel toward patients (Zyoud et al., 2013; Lazarevik and Kasapinov, 2015). Our finding was contradicted with a web-based survey conducted in Macedonia, Serbia, and Bulgaria (Lazarevik and Kasapinov, 2015).

In the current study, most heart failure (HF) patients showed good treatment adherence (60.9%). This result was higher than a study in Yemen (45.8%) (Alakhali et al., 2013) but lower than in the Brazil (77%) (Da Silva et al., 2015).

It also aligned with findings from other studies (Murray et al., 2007; Bisharat et al., 2012; Zhao et al., 2015). These variations could be due to differences in how treatment adherence is measured, the patient-care strategies used by pharmacists, and differences in the definition of adherence. For example, our study was conducted at DBCSH, a referral hospital in a resource-limited setting, with participants dealing with complex medical conditions and multiple medications, leading to a lower treatment adherence rate compared to other study locations. Low adherence among patients with HF is adversely affecting clinical results and leading to greater HF exacerbations, lower physical activity, and a greater likelihood of hospitalization and mortality. Our study found that study participants had a low medication adherence rate; thus, effective interventions are needed to increase medication adherence and achieve improved medical outcomes.

Participants taking five or more drugs were 68% less likely to adhere to treatment compared to those using only one drug. This finding aligns with studies conducted in the United States of America and Iran, emphasizing that a higher pill burden could decrease treatment adherence (Knafl and Riegel, 2014b).

In conclusion, the study revealed a treatment satisfaction rate of 67.6% and a medication adherence rate of 60.9% among HF patients. The statistically significant association between drug-drug interactions (DDI) and the number of drugs used highlights the importance of addressing these factors for improving treatment adherence. The correlation between medication adherence and drug-drug interactions remains a possible pseudo-correlation via the number of medications taken. Therefore, it is imperative for medical facilities to ensure the provision of quality services and all necessary resources to enhance treatment satisfaction and medication adherence among heart failure patients. This may involve optimizing healthcare processes, reducing drug interactions, and promoting comprehensive patient care.