Hypertension-related knowledge, medication adherence and health-related quality of life (HRQoL) among hypertensive patients in Islamabad, Pakistan

Purpose: To determine knowledge regarding hypertension, adherence to medication and HealthRelated Quality of Life (HRQoL), and their associations in hypertensive patients in Pakistan. Methods: A cross-sectional study was conducted among 384 hypertensive patients attending a tertiary health care public sector hospital in Islamabad, Pakistan. Data were collected using knowledge questionnaire regarding hypertension, Morisky Medication Adherence Scale, and EuroQol (EQ-5D) scale. Results: The mean systolic and diastolic blood pressures of the 384 patients were 140.39 ± 15.485 and 88.74 ± 10.683 mmHg, respectively. The coefficient of correlation between knowledge regarding hypertension and adherence was 0.638 (p < 0.001), showing a positive association. The correlation coefficient between knowledge and HRQoL was 0.709 (p < 0.001), suggesting a good association. The correlation coefficient between adherence to medication and HRQoL was 0.545 (p < 0.001), which indicated a positive correlation. Conclusion: These results indicate that there are statistically significant associations between hypertension knowledge and HRQoL, hypertension knowledge and medication adherence, and between adherence and HRQoL in the hypertensive patients studied.


INTRODUCTION
Hypertension (HTN) is a chronic disease of worldwide concern. It is an important and avoidable risk factor for cardiovascular diseases. Hypertension has substantial negative impacts on health, and results in needless morbidity and mortality. It is believed to be responsible for > 5.8 % of deaths worldwide, and loss of about 11.9 % of life expectancy. The success rate in control of hypertension is poor all over the world. Pakistan is faced with an epidemic of hypertension as well as cardiovascular (CV) diseases [1]. Life expectancy in Pakistan (62 years) is 17 -20 years lower than the range in developed countries [2]. Low knowledge regarding hypertension as well as other cardiovascular diseases has been reported on the continent. Data relating to knowledge as well as risk factors related to hypertension are not available in Pakistan. This has become a major public health and clinical issue in Pakistan. It has been reported that the prevalence of hypertension in Pakistan is 33 %. Every third individual aged above forty years is prone to different diseases. It has also been reported that only 50 % of hypertensive individuals were diagnosed, while only about half of the diagnosed patients received treatment. Half of those diagnosed patients treated for hypertension were prescribed with correct medication for effective control of hypertension. Thus, only 12.5 % of hypertension cases were properly controlled [1].
The present study was aimed at assessing the level of hypertension-related knowledge, adherence to medication and HRQoL among hypertensive patients in Islamabad, Pakistan and to assess the association between hypertension related knowledge, medication adherence and HRQoL.

Study design and settings
A questionnaire-based, cross sectional study was adopted to assess knowledge, HRQoL and blood pressure of hypertensive patients. Since the prevalence of hypertension is 33 % in Pakistan, a sample of 384 patients, based on prevalence [1] was recruited from Federal Government Poly Clinic (Postgraduate Medical Institute). The study was conducted from August to November 2017.

Inclusion criteria
Patients aged thirty years and above, who were diagnosed with hypertension, and were receiving treatment for high blood pressure in the previous 6-months, and patients with the ability to write or speak Urdu (Pakistan's official language) were recruited for this study.

Exclusion criteria
Patients aged less than thirty years, and those aged over seventy years; pregnant women, patients with co-morbidities, patients having dementia, and immigrants were excluded from this study.

Ethical approval
Approval for this study was obtained from the Ethical Committee of Poly Clinic Hospital (affiliated to Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad) (approval no. FGPC.1/12/2016/Ethical Committee). The study was conducted according to ethical principles as described in Helsinki Declaration of 1964, revised in 2013 [3]. Prior to collection of data, written consent was obtained from the hypertensive patients.

Data collection
Knowledge questionnaire about hypertension, Morisky medication adherence scale (MMAS-U) and EuroQol (EQ-5D) scale were utilized for data collection.

Assessment of knowledge of hypertension
Hypertension knowledge questionnaire in Urdu was developed after extensive survey of literature [4]. It consisted of 22 questions. Each question required a 'Yes', 'No' or 'Do Not Know' response. Knowledge was evaluated by scoring 1 for a correct response, and 0 for a wrong response. The response of 'Do Not Know' was also scored zero. Knowledge was measured on a scale from a minimum of 0 to maximum of 22. Scores < 10 were categorized as poor, while scores in the ranges of 10 -18 and 19 -22 were categorized as moderate and adequate knowledge, respectively, about hypertension.

Assessment of medication adherence
The Urdu version of Medication Adherence questionnaire by Morisky was used to evaluate adherence to treatment. It included seven questions having responses of Yes or No, and 1 question as a 5-point Likert type scale. Each ''No'' response was scored 1, and each ''Yes'' response scored 0 except for question 5, in which each ''Yes'' response was scored 1. Adherence scores were grouped viz: 8 for high adherence, 6 -7 for medium adherence, and ˂ 6 for low adherence [5].

Assessment of HRQoL
The HRQoL was measured in hypertensive patients using EuroQol EQ-5D scale which included 2 parts [6]. The first part comprised 5 dimensions of health: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension had three levels viz: no problem, some or moderate problems and extreme problem corresponding to levels 1, 2, and 3, respectively [7].
For Pakistani population, EQ-5D preference weight was not available for each state of health. Therefore, as EQ-5D Index score, these preference weights were derived from Time Trade-Off (TTO) tariff of preference weights of UK general population [8]. The second part consisted of visual analogue scale (VAS). It determined the respondent's self-rated status of health on a graduated (0 -100) scale, with a score of 100 as the best imaginable state of health, and a score of 0 as the worst imaginable state of health, and higher scores for higher HRQoL. The Urdu version of EQ-5D was provided on request, by EuroQol. This study was also registered with EuroQol.

Blood pressure measurement
The blood pressure of each patient was measured using a calibrated mercury sphygmomanometer.

Data analysis
Data were analyzed statistically using SPSS software version 21.0. Spearman's test was performed to assess any association between knowledge, medication adherence and HRQoL. Measurement data are expressed as mean ± standard deviation (SD).

Patients' demographics
Cronbach's alpha value was 0.755 for hypertension knowledge, 0.747 for adherence, and 0.712 for EQ-5D questionnaires. Three hundred and eighty-four (384) HTN patients were enrolled in this study. Table 1 shows the sociodemographic variables as well as frequency distribution of the hypertensive patients.
Table shows that 138 out of the 384 patients were in the age range of 41 -50 years, with 56 % as males. Three hundred and eighty-three of the patients (99.7 %) were married. Mean duration of disease was 3.31 ± 2.13 years. Majority of the patients (101, 26.3 %) had matriculation level of education, while 156 patients (40.6 %) were either housewives or house makers. Two hundred and twenty-one patients (57.6 %) had a monthly income of more than 15,000 Pakistan Rupees, and 220 patients (57.3 %) were urban dwellers.    Table 3 shows knowledge scores of patients. The mean knowledge score was 13.26 ± 5.16 and median score was 13. It also indicates the relationship between demographic characteristics and knowledge. Differences were statistically significant when age, gender, education, occupation and monthly income were analyzed (p ˂ 0.001).

EQ-5D health status
The 15 different health states of EQ-5D described are shown in Table 7.

Association between knowledge and medication adherence
The coefficient of correlation between knowledge related to hypertension and medication adherence was 0.638 (p < 0.001) which indicated positive correlation.

Association between knowledge and HRQoL
The coefficient of correlation between knowledge regarding hypertension and HRQoL was 0.709 (p < 0.001) which indicated positive correlation. The coefficient of correlation between knowledge and VAS was 0.459 (p < 0.001) which also indicated positive correlation.

Association between medication adherence and HRQoL
The coefficient of correlation between adherence and HRQoL was 0.545 (p < 0.001) which indicated positive correlation. The coefficient of correlation between adherence and VAS was 0.328 (p < 0.001), which also indicated fair correlation.

DISCUSSION
The results from the present study showed that among the HTN patients studied, knowledge regarding hypertension had good association with medication adherence. Some studies have also reported a good relationship between hypertension-related awareness and adherence to medication [9,10]. It has been reported that disease-related knowledge is one of the key factors in obtaining successful adherence to therapy [11]. In contrast, a study has also reported no association between knowledge regarding hypertension and adherence to medication [12].
Reduced HRQoL was seen in the HTN patients. The poor results in HRQoL are consistent with those reported in previous studies on pulmonary and essential hypertension patients [13][14][15]. Nonetheless, some studies of similar nature have reported mixed results. One study reported a statistically significant relationship among education, monthly income and HRQoL [16]. In another study, it was reported that age was the only factor that showed significant relationship with HRQoL [17], while another study reported that gender and income were the only variables significantly related to HRQoL [18]. A study highlighted that age, gender, education, employment status, annual household income, obesity and hypertension were significantly associated with HRQoL [19].
In the present study, knowledge regarding hypertension had good association with HRQoL and visual analogue scale. It has been demonstrated that after counseling on lifestyle modifications, energy/fatigue scores (a quality-oflife scale) were significantly improved in hypertensive patients [20]. Moreover, it has been reported that patient education, life style modifications and motivation for health resulted in improvement in the mean score of QOL of hypertensive patients [21]. In another study, it was indicated that EQ-5D index and EQ-5D VAS scores of hypertensive patients were significantly improved after pharmaceutical care intervention [13]. In addition, the HRQoL of patients have been improved by promoting patient's care activities and by supporting their QoL domains [22].
Results from the present study also showed that medication adherence had good association with HRQoL and a fair correlation with visual analogue scale. In a population-based survey in Brazil, poor HRQoL was associated with lower medication adherence among hypertensive patients [23]. It was also reported that better HRQoL was associated with higher medication adherence among patients with asthma in Japan [24]. However, another study reported a negative correlation between HRQoL and adherence in hypertensive patients [25].
A number of challenges are faced by developing countries in attempts to provide optimal healthcare to their citizens. Within this context, Pakistan is the 6 th most populous country in the world, with about 40 million people living below national poverty line, and half of the adult population is illiterate. More important is the fact that across regions, disparities in income per capita have persisted or even widened [22].
It is possible to attain optimized pharmaceutical care through provision of education to patients regarding self-management. This will result in improvement of their knowledge and understanding about hypertension, adherence to therapy, and coping strategies. The present research revealed that a large portion of patients had poor knowledge of hypertension, and had little information regarding management and control of the disease.

Limitations of the study
In current study, majority of hypertensive patients were in the age range of 41-50 years, and above that age majority of them had comorbidities like diabetes which limited the number of patients that met the inclusion criteria for this study. Therefore, the results of the current study cannot be generalized. .

CONCLUSION
The results obtained in this study show that knowledge about hypertension has a good association with medication adherence and HRQoL. A good association also exists between medication adherence and HRQoL.