Comparison of knowledge, attitude and practices among apparent treatment resistant hypertensive patients and non-apparent treatment resistant hypertensive patients in a tertiary care center

INTRODUCTION

Globally, hypertension (HTN) affects over one billion people, seven million of whom die annually as a direct result of it.¹ HTN is a non-communicable disease that has become a serious public health problem and a leading cause of death and disability, along with resistant HTN in developing nations.² Approximately 26% of the adult population in the world is affected by HTN. This number is estimated to increase to 29% by 2025, i.e., from 972 million as of the year 2000 to 1.56 billion.²

HTN is a major worldwide public health problem as it is associated with major cardiac diseases, stroke, premature deaths, etc. HTN is considered the tip of the iceberg and is often diagnosed for seeking treatment for other health problems.³ The ‘rule of halves’ for HTN states that: ‘half the people with high blood pressure are not known (“rule 1”), half of those known are not treated (“rule 2”) and half of those treated are not controlled (“rule 3”),⁴ and in that there is further partition called apparent treatment resistant hypertension (aTRH). Resistant HTN has been consistently defined as high blood pressure (BP) requiring four or more medications for treatment, but this definition also includes those whose BP remains uncontrolled, not because of antihypertensive treatment failure, but for a variety of other reasons. Hence, use of the terms ‘‘true resistant hypertension’’ versus ‘‘apparent resistant hypertension,’’ with the latter including those patients in whom common causes of poor BP control could not be excluded.⁵ The increasing prevalence of HTN as well as aTRH is mainly due to a lack of understanding about the disease, insufficient patient education programs, low economic status, etc, which might even lead to medication non-adherence. There is a paucity of information about knowledge, attitude, and practices (KAPs) among apparent treatment-resistant hypertensive patients in India.

Therefore, this area is being targeted for specific assessment and intervention to overcome any challenge, obtain adequate health awareness about HTN, and understand lifestyle behavior modifications which play an important role in successful control of the disease, its symptoms, and prevent short- and long-term complications. The primary objective of the study is to evaluate knowledge, attitude, and practices among patients with aTRH presenting to a tertiary care hospital in Delhi. The secondary objective of the study is to compare knowledge, attitude, and practices between aTRH and non-aTRH hypertensive patients.

MATERIAL AND METHODS

The case control study was conducted in the Department of Medicine at University College of Medical Sciences and associated Guru Teg Bahadur Hospital, Delhi, for 3 years. Subjects were recruited from the Medicine out patient department and special clinics. Despite an intensive search of the literature, no study could be found on KAP regarding management of HTN among aTRH patients. Hence, considering the logistical constraints of time and resources for the present study, a minimum of 100 subjects were recruited, with inclusion of 50 subjects each of aTRH and non-aTRH patients. aTRH is defined as BP ≥140/90mmHg despite concurrent use of antihypertensive medications from three different drug classes or drugs from ≥ 4 antihypertensive drug classes, regardless of BP. One of the three or four agents should be a diuretic, and all agents should be prescribed at optimal dose amounts. When issues of dosing, medication adherence, and white coat HTN have not yet been ruled out, the term aTRH is utilized in lieu of true resistant patients.

Consecutive adult hypertensive patients age ≥18 years, who consented to the study and were on antihypertensive agents for at least 6 months, were included. Patients who could not understand Hindi or English were excluded. All participants were interviewed using a validated questionnaire. The questionnaire had information regarding demographic profile, KAP in the management of HTN. The questionnaire was administered by the investigator to the participants in a language understood by them.

A case record form was filled out for each subject and included a socio-demographic profile, treatment history, and relevant clinical and laboratory data. The weight of each patient was measured in kilograms using a bathroom scale. The waist circumference of each patient was measured in centimeters at the level of the highest point of the iliac crest for each patient and central obesity would be defined as a waist circumference > 90 cm for South Asian men and >80 cm for South Asian women.⁶ Height was measured with a fixed stadiometer. Body mass index (BMI) was calculated as weight divided by height square (kg/m²). Two consecutive resting seated blood pressure was recorded 10 minutes apart, using an automated blood pressure instrument. Detailed treatment history was taken, which included a number of drugs, name and class of anti-hypertensive with their respective doses, use of over-the-counter drugs, and side effects, if any.

For medication knowledge, subjects were asked five questions on each medicine that they were taking, including the name of the drug, dose, frequency, indication, and how and when it was taken. The total number of correct answers with respect to the total number of questions was expressed as percentage.⁷ Patients were interviewed by the doctor regarding the medication adherence as per the Adherence to Refills and Medication Scale (ARMS),⁸ which includes a set of 12 questions. The range of possible scores is 12 to 48. Lower scores indicate better adherence. Scores can be treated as a continuous measure or dichotomized as 12 or >12. Presence of Depression was assessed as per the PHQ-9 scale.⁹

KAP were assessed by a validated questionnaire having 13 questions of knowledge, five questions of attitude, and nine questions of practice, as shown in Tables 1-3. Knowledge and attitude answers were scored one for correct and zero for incorrect whereas, the practice answers were scored two for frequent adherence towards the guidelines, one for occasional adherence and zero for non-adherence (never) for all the questions except question 4, 7, and 8, in which a response of never was scored two, occasional was scored one and frequent was scored zero. The total score for each outcome variable was obtained by adding the score obtained from each question.

RESULTS

DISCUSSION

In the present study, we observed no significant difference in mean age between the aTRH and non-aTRH groups. Hung et al.¹⁰ (2014) found a higher prevalence of aTRH in the elderly (>60years). Higher prevalence of aTRH in males was reported in a study by Wu et al. (2019) (51.48% vs 40.65%).¹¹ Egan et al. (2013) showed the same result of higher prevalence in males.¹² In our study, males were more in the aTRH group (52% vs. 48%), but not statistically significantly. This may be due to local female preponderance in attendance at medical outdoor events in general.

Obesity is a major health problem in developed as well as developing countries. There is a relative increased risk of HTN as well as aTRH in overweight people. We observed slightly higher BMI in the aTRH group, although statistically insignificant. Many studies have shown BMI as an important risk factor for aTRH. Shimbo et al. (2013), reported that those with aTRH also had a higher mean BMI.¹³ Viazzi et al. (2017) also found significantly higher BMI in aTRH patients.¹⁴

Lifestyle factors play an important role in the pathogenesis of HTN. Smoking and chronic alcohol use are associated with increased incidence of diabetes, HTN, stroke, and metabolic syndrome. Excessive alcohol intake is usually associated with uncontrolled HTN. In our study, no significant difference in alcohol and smoking habits in the two groups was found. We found a slightly higher prevalence of tobacco usage in cases as compared to controls (2.90 vs 2.74), but the results were not statistically significant. Shimbo et al. (2013), found no significant difference in the prevalence of heavy alcohol use between participants with and without aTRH.¹³

Our study showed that the aTRH group had higher per capita income as compared to controls. A study conducted by Thomas et al. (2016) analyzed the data from the CRIC study and showed that aTRH patients were more likely to have a per capita income of <$20000, which was consistent with the results obtained in our study.¹⁵ This can be explained by the fact that financially good families having higher per capita income have a more sedentary lifestyle in terms of dietary habits as well as outdoor activities. Non-ATRH patients were more financially dependent as compared to aTRH, but the tests were not statistically significant. This was not expected, as more financial dependence means more problems regarding refilling medication. No literature has been published that shows a relationship between financial dependency and aTRH.

Multiple cross-sectional studies comparing patients with aTRH to those without have suggested increased frequency of target organ damage and later cardiovascular complications. This is due to increased frequency of various co-morbidities which are present in increased frequency in patients with aTRH. In our study, diabetes (26%) was the most common co-morbidity, followed by CKD (22%), Obesity (22%), CAD, COPD, and depression in the aTRH group. The total number of co-morbidities was higher in the aTRH group as compared to the non-aTRH, but not statistically significantly. In the study reported by Viazzi et al. (2017) the aTRH patients were being followed up for renal outcomes, and it was found that they were more likely to develop low eGFR as compared to non-aTRH patients.¹⁴ Hung et al.,(2014) found that patients with aTRH had a higher prevalence of co-morbidities, such as diabetes mellitus, hyperlipidemia, ischemic heart disease, peripheral vascular disease, valvular heart disease, pulmonary disease, and renal disease, when compared to non-aTRH patients (p values <0.001).¹⁰ Carey et al.(2019) found the same result of higher prevalence of aTRH in diabetic and CKD patients.¹⁶

Medication non-adherence is a known behavioral contributor to poor BP control that puts patients with HTN at elevated cardiovascular risk. There are different scales to measure medication adherence, such as MARS (Medication Adherence Rating Scale),¹⁷ ASRQ (Adherence Self Report Questionnaire),¹⁸ BARS (Brief Adherence Rating Scale),¹⁹ MORISKY Scale,⁸ ARMS (Adherence to Refills and Medication Scale).⁸ In our study, we used the ARMS scale for calculating adherence, in which a subject can obtain a score of 12 or >12. A score of 12 means good adherence and anything above this score means poor adherence. None of our subjects had scored 12. Although the aTRH group had a higher total score on the ARMS scale as compared to the non-aTRH group, this indicates poor adherence of the aTRH group (p <0.001). In the meta-analytic study conducted by Durand et al. in 2017, the prevalence of non-adherence varied between the studies, ranging from 3.3% to 86.1%.²⁰ A similar study done by Malik et al. (2014) comparing KAP between controlled hypertensives and uncontrolled hypertensives found that controlled hypertensives were significantly more adherent to antihypertensive drugs (80.4% vs. 22.8%).¹

It was found in many studies that depressive patients have increased sympathetic tone and increased secretion of adrenocorticotropic hormones; therefore, pathophysiologically plausible that depression and HTN affect one another. Secondly, anti-depressants like MAO inhibitors can exacerbate HTN. Thirdly, due to symptoms of depression, patients can forget to take anti-hypertensive drugs. Above mentioned reasons clearly depict that depressed patients are more likely to have uncontrolled HTN. In our study, we applied the PHQ-9 scale and found that although depression was more prevalent in the aTRH group, but was not statistically significant (p-value=0.627). This states that there is a slight increased risk of depression in the aTRH group as compared to the non-aTRH group. Similar results were found in a study done by Shimbo et al.(2013), that there were elevated depressive symptoms in the aTRH group as compared to non-aTRH patients (12.1% vs. 11.7%), but results were not significant.¹³ Study done by A.F. Rubio Guerra et al. (2013) showed that depression is a common feature in patients experiencing uncontrolled HTN and found a significant positive correlation between self-measured depression test and higher blood pressure.²¹

Knowledge, perceptions, and attitudes of people towards HTN have a significant role in changing lifestyle, including modifiable risk factors. Based upon a validated questionnaire, the aTRH group in the present study showed an average score of 4.9 in knowledge, 2.3 in attitude, and 9.7 in practice. No similar study about the KAP score in aTRH was found. But, by several studies such as Durand et al.,²⁰(2017) Malik et al.¹ (2014) and Durand et al.²⁰(2017) it is clear that leading cause of aTRH is poor drug adherence, other causes being poor lifestyle, obesity, physical inactivity, and all of these are modifiable by just increasing the knowledge and changing the attitude and practices about HTN which results in better blood pressure control. A study done by Gonzalez et al. (1990), indicated that the most important factor to increase compliance and blood pressure control is knowledge about HTN.²²

In the present study, we have also carried out a comparison of KAP mean scores about HTN via a validated questionnaire among aTRH and non-aTRH patient groups. We found that aTRH had poor knowledge about HTN, had poor practices and attitude towards HTN compared to non-aTRH. Till present date, no study has been done for assessing KAP scores among aTRH patients as well as comparing mean KAP scores between aTRH versus non-aTRH subjects. Malik. et al. (2014) studied the KAP score in two groups: controlled and uncontrolled hypertensives. They observed that most participants from the control group had more knowledge about HTN.¹ Only 33.3% of HTN-controlled and 29.1% of uncontrolled group patients knew that even a person with high BP might not feel any symptoms. Furthermore, the HTN-controlled patients were significantly more adherent to antihypertensive drugs than uncontrolled patients.¹ In India, Ahmad S et al. (2015) studied the knowledge, attitude and practice of hypertensive patients and found that out of 354 patients, 72.3%, 77.7%, and 82.8% had poor score of knowledge, attitude and practices of HTN respectively and those with poor scorers of KAP were having higher mean systolic and diastolic blood pressures which was found to be statistically significant.²³

Earlier studies clearly depict that uncontrolled hypertensive patient are resistant not just because of failure of their treatment regimen but due to inadequate knowledge, improper attitude, and practices towards HTN, and that this group, if compared to controlled hypertensives, will have poorer knowledge, attitude, and practices about HTN.

CONCLUSION

We found that the KAP scores of the non-aTRH group were better than aTRH group, which explains their good blood pressure control. Hence, educating about HTN and its related attitudes and practices should be our primary goal to decrease the prevalence of aTRH and its related morbidities and mortalities.