Non-Adherence Related Factors to Antihypertensive Medications Among Hypertensive Patients on Follow up at Nedjo General Hospital in West Ethiopia

1. INTRODUCTION

Hypertension (HTN) is an overwhelming global challenge [1, 2]. Hypertension is defined as persistently elevated arterial Blood Pressure (BP) and it is identified as one of the most significant risk factors for Cardiovascular (CV) disease. Increasing awareness and diagnosis of hypertension, and improving control of BP with appropriate treatment are considered critical public health initiatives to reduce CV morbidity and mortality [3].

A study done on global burden of blood-pressure-related disease revealed that Worldwide, 7·6 million premature deaths (about 13·5% of the global total) and 92 million Disability-Adjusted Life Years (DALYs) (6·0% of the global total) were attributed to high blood pressure [2]. Even though there are medications that are used to treat hypertension, because of large proportion of patients not taking these medicines as prescribed the benefits of these drugs are not being realized and this indirectly raises the issue of therapeutic adherence among hypertensive persons [4].

The most frequently used definition of adherence is “the extent to which a person’s behavior – taking medication, following a diet, executing lifestyle changes – follows medical advice” [5]. Adherence has also been defined as “the extent to which patient behavior corresponds with recommendations from a health care provider” [5]. A review from the 2095 articles identified that therapeutic non-adherence occurs when an individual’s health-seeking behavior lacks similarity with the recommendations as prescribed [6].

Non adherence to treatment medication and lifestyle modification is a complicated issue affecting patients’ health, health expenditure, and resources’ utilization while adherence to Antihypertensive Treatment (AHT) has been associated with improved blood pressure (BP), decreased hospitalizations rates, and lower medical care costs [7-9]. Survey conducted 2003-2004 showed only 37% of hypertensive patients have their blood pressure controlled [10]. Uncontrolled high blood pressure indirectly raises the issue of therapeutic adherence among hypertensive persons [11]. According to the WHO, poor adherence to treatment is the most important cause of uncontrolled blood pressure and only 20 to 80% of patients receiving treatment for hypertension in real life situations are considered to be “good compliers” [5].

Different studies had identified factors determining the levels of antihypertensive drug adherence such as; the complexity of the treatment, the drugs’ side effects, the balance between established medical guidelines and their own convictions, communication between patient and doctor, patient’s satisfaction with the healthcare system, socio-economic factors, socio-demographic factors, the cost of treatment and lack of medical insurance [3, 6, 7, 12-25].

This study aimed to examine adherence to antihypertensive medication and to assess factors associated with non-adherence to medications at Nedjo General Hospital. Identification of non-adherence related factors will help the healthcare professionals and patients to work on those factors to improve non-adherence. The findings of the study will also suggest strategies for improving non-adherence. As there was no study done in West Ethiopia, this study will help as a base to perform further studies.

2. METHODS AND PARTICIPANTS

3. RESULTS

A total of 172 hypertensive patients out of the 184 cases were included in the study. Twelve of the respondents were excluded by the exclusion criteria. Of this 5 were not volunteer to participate while 7 patients, even though they are volunteer they did not fulfill the inclusion criteria because they were newly diagnosed for hypertension and medication initiation was less than one year. So the response rate was 93.5%. Majority of the respondents were females (55.8%). The mean age of the respondents was 51.5 + 12.1 years. Out of the study participants 49.4% were in the age range of 35-54 years. More than half of the study participants 119 (69.2%) were married and 84 (48.8%) were farmers (Table 1).

Most of the respondents, 109 (63.4%) were taking a single antihypertensive medication and 48 (27.9%) respondents were taking two antihypertensive medication. Among 172 study participants, 72 (41.9%) respondents were treated for less than two years and 51 (29.7%) were treated for > 5 years. Regarding knowledge of the study participants about hypertension and its treatment, more than half of the study participants 112 (65.1%) had inadequate knowledge about hypertension and its treatment (Table 2).

Most of the study participants 118 (68.6%) were non-adherent to antihypertensive medications, whereas 54 (31.4%) were adherent (Table 2). For non-adherent respondents 118 (68.6%), the major reasons for non-adherence were forgetfulness 81 (47.1%), followed by inability to buy medications 29 (16.9%) (Table 3).

In our study regarding antihypertensive medications Hydrochlorothiazide, 45 (26.2%) and Enalapril, 44 (25.6%) were the commonly prescribed antihypertensive medications followed by Nifedipine 20 (11.6%) and a combination of Enalapril plus Hydrochlorothiazide 20 (11.6%) Fig. (1).

The bivariable analysis showed that non-adherence was associated with marital status, occupation, place of residence, level of education, income status, number of antihypertensive medication, physical activity, extra salt intake and knowledge of hypertension. However, other factors did not show statistically significant association with non-adherence (Table 4). Majority of patients with age > 55 years, patients who live in rural, patients who are illiterate and their level of education was elementary and patients with low level of Knowledge about hypertension and treatment were non-adherent to their antihypertensive medication (Table 4).

Multivariable logistic regression have shown that variables such as age, level of education, monthly income status, duration of treatment, physical activity status and knowledge about hypertension and treatment were associated with non-adherence to antihypertensive medications. Factors like marital status, occupation, place of residence, number of antihypertensive medication and extra salt intake have shown significant association in bivariable analysis but the effect was absent after controlling for confounding factors (Table 5).

4. DISCUSSION

Despite the availability of effective treatments, studies have shown that in many countries less than 25% of patients treated for hypertension achieve optimum blood pressure. Poor adherence has been identified as the main cause of failure to control hypertension [5]. In this study, only 31.4% of the study participants were adherent to their medication. This is comparable to studies reported from hospitals in Ghana and Nigeria 33.3%, Kenya 31.8%, Palestine 36.2%, Nepal 35.4% [17, 28-30]. When we compare the current finding to other studies done in Ethiopia, adherence to antihypertensive treatment was lower than studies done in University of Gondar Referral Hospital 64.6%, Black Lion Hospital 69.2%, Northern Ethiopia 52.9%, Adama Referral Hospital 59.5% [13-16]. Similarly the adherence to antihypertensive treatment found in current study was lower than studies done in Ghana 68.7%, Nigeria 44.7%, Zambia 83%, Malaysia 48.7%, Brazil 52.9%, Italy 48.6%, USA 57.6%, Pakistan 77%, United Arab Emirates 54.4% [12, 18-25]. The reason for the difference might be due to better access and skilled health care professionals for the patients in these regions and countries. It could also be due to participants’ better knowledge toward hypertension and its management than the current study area. The results of this study suggest that greater effort is needed to improve patient adherence to antihypertensive medications at Nedjo General Hospital. To improve adherence the following intervention should be done: education on the use of medicines, management of disease and treatment in conjunction with patients, adherence education, multidisciplinary care, training in monitoring adherence, more intensive intervention by increasing the number and duration of contacts [5]. In addition involving the patient's family members and friends in providing education on the importance of adherence to antihypertensive medications and telling them the consequences if the patient is not adherent to his medication should also be targeted/ adopted.

The results obtained from multivariable logistic regression analysis of the present study revealed that younger age, being illiterate, income status of <500 Ethiopian birr, duration of treatments of >5 years, physical inactivity and knowledge deficit about hypertension were associated with non-adherence.

In this study, age was significantly associated (p=0.035) with non-adherence observed in younger age. The present finding is consistent with that reported by other studies from Adama Referral Hospital [16], in hospitals of Ghana and Nigeria [17], Nigeria [18] and Pakistan [24]. A probable reason for better adherence in elderly might be because of a better care given by the family members for patients in this age group. The other reason could be patients with younger age could be reluctant for their medication. Older people might have more concern about their health than younger patients, so that older patients’ non-compliance is non-intentional in most cases. As a result, if they can get the necessary help from healthcare providers or family members, they may be more likely to be compliant with therapies [6].

Present study revealed that participants who were illiterate (p=0.049) and participants whom educational status was elementary (p=0.002) were significantly associated with non-adherence. Similar results were reported from studies in hospitals of Ghana and Nigeria [17], Zambia [19], Pakistan [24] and Nepal [30]. This could be due to lack of awareness about hypertension, its management and medications for this condition in this study area. It may be expected that patients with higher educational level should have better knowledge about the disease and therapy and therefore be more compliant [6]. To improve adherence in illiterate patients and patients with low level of education, interventions to optimize adherence must go beyond the provision of advice and prescriptions; supplementing oral teaching with written materials are required to improve adherence [5]. Using simple, everyday language, when explaining about the disease and giving instructions will also improve their adherence.

Different studies have identified inability to afford the cost of medications as an important barrier to medication adherence [14, 17, 24, 29]; however these studies did not show association of medication adherence with level of income. Unlike thus studies, this study showed an association between level of income and non-adherence (p=0.011) with non-adherence 18.51 times more likely to occur in patients with low income than higher income. The reason could be because of patients with low income cannot able to afford the cost of medication.

In this study, duration of treatment was significantly associated (p=0.041) with non-adherence and patients on hypertension treatment for more than or equal to five years were 5.41 times more likely to be non-adherent than those with duration of treatments of less than two years. Similar finding was reported from study done in Black Lion Hospital [14]. This could be because long use of drugs would burden the patient and lead to forget their medication and discontinue medication too soon. Beside once the patient blood pressure had got stabilized they might felt to be in better condition.

A study done in Nigeria [27] revealed that exercise is a facilitator for adherence to antihypertensive medication. The result of present study showed that, physical inactivity was significantly associated (p=0.001) with non-adherence. Physicians should help patients find an activity that they enjoy, because enjoyment will increase their adherence [31].

In this study, lack of knowledge about hypertension and its treatment was significantly associated with non-adherence. The present finding is consistent with that reported by other studies from University of Gondar Referral Hospital [13], Adama Referral Hospital [16], in hospitals of Ghana and Nigeria [17], Pakistan [24], United Arab Emirates [25] and Congo [32]. Right knowledge about HTN and its treatment creates a clear understanding and avoids confusion about the treatment and the disease condition [5].

The present study revealed that the major reasons for non-adherence were forgetfulness followed by inability to buy medications. To improve non adherence related to forgetfulness we recommend the patients to use medication boxes with dates/times written on them (“Pill organizers”) or setting an alarm clock. For patients with lack of finance, we recommend the government to find a means in which patients with lack of finance that cannot afford the cost of medication can get the medications; for example providing medications for free for patients that cannot afford the cost of medication, creating drug discount cards that can be helpful to patients who can afford to pay part of their prescription costs.

Strengths of our study were that adherence to antihypertensive medications was measured by using the 8-item Morisky medication adherence scale and data were collected from patients’ card and by face to face interview with patients; this helped us to have more complete information. Limitations of our study were that, this study was conducted only in government District Hospitals in Nedjo Town and did not include patients who attended private Hospitals. Therefore results cannot be generalized to all hypertension patients in Nedjo woreda. However, the results have important insights for same hospitals within the same characteristics. Self-reporting was used for measuring adherence. This method has the disadvantages of recall bias and eliciting only socially acceptable responses and hence, may, lead to overestimation of some of the results, because they are self- reports by the patients which can be misleading.

CONCLUSION

In general, a finding of this study revealed that an adherence status of study participants was low. Thus greater effort is needed to improve patient adherence to antihypertensive medications. The major reasons for non-adherence among the study participants were forgetfulness, followed by inability to buy medications. Factors such as age, educational level, income status, duration of treatments, physical activity and knowledge deficit about hypertension and its treatment were significantly associated with non-adherence. We recommend that practitioners should always look for poor adherence and enhance adherence by emphasizing the value of a patient’s regimen, making the regimen simple, and customizing the regimen to the patient’s lifestyle. Health care professionals should assist hypertensive patients develop systems that will remind them to take their medications. There should be total collaboration between all the health professionals in the institution to promote patient education and medication counseling.

REFERENCES