High blood pressure (BP) is often asymptomatic and usually referred to as the silent killer. It is responsible for approximately half of the incidence of stroke and ischemic heart diseases, and it is the leading cause of mortality worldwide, posing a formidable challenge to healthcare [
Globally, hypertension is one of the most prevalent chronic diseases and one of the greatest public health concerns [
One goal of antihypertensive therapy is to achieve optimal BP control and reduce co-occurring chronic conditions [
Antihypertensive medications, along with lifestyle improvements, play important roles to achieve optimal BP control and reduce their complications [
Only a few studies in Palestine examined the adherence of hypertensive patients to the treatment. These studies revealed a level of adherence ranging between 36.8% and 54.2% [
A cross-sectional descriptive design was used in this study.
The target population included adults (over 18 years) who agreed to participate, had been diagnosed with hypertension for at least one year prior to the time of data collection, and received at least one antihypertensive agent. Hypertensive patients who met these criteria were included in the study. Patients who had other comorbidities were not excluded from this study. This helped to explore if the presence of comorbidity had an impact on the participants’ level of adherence or not. On the contrary, patients who were under the age of 18, were diagnosed with hypertension for less than one year, or did not receive at least one antihypertensive drug were excluded from the study.
A convenience sample of 689 participants was recruited randomly from primary healthcare centers across the Gaza Strip. The purpose of the study and their involvement were explained to them before they were invited to participate. The sample size was calculated on the basis of the annual report from the Palestinian Ministry of Health [
The data collection instrument consisted of three parts. The first part contained questions regarding demographic data about the participants along with history of the disease and medications they received. The second part was the Hill-Bone Compliance to High Blood Pressure Therapy Scale (Hill-Bone CHBPTS), which was developed by Kim et al. in 2000 [
The original questionnaire consists of 14 questions which fall into three categories: medication adherence, dietary regimen adherence, and medical appointment adherence. A fifteenth item, related to how often participants eat extra salty food such as pickles, was added to the questionnaire by the research team because salty foods, as well as adding extra salt to food, are important parts of the local diet. Each item was measured on a four-point Likert scale: never (1), occasionally (2), often (3), and always (4); the minimum and maximum possible scores are 15 and 60, respectively. While a lower score means a higher degree of adherence, a higher score means higher level of nonadherence to treatment regimens. Based upon the review of the literature, the researchers prepared a list of 17 items of possible barriers for adherence to hypertension treatment. Each item was measured on a five-point Likert scale in which 1 = strongly agree and 5 = strongly disagree.
The Hill-Bone CHBPTS was translated into Arabic to remove language barriers. This was done by three bilingual members of the research team. Then, face validity of the instrument was assessed by two bilingual healthcare professionals who reviewed the translation. The reviewers provided a few suggestions to improve the quality of the translation and to make it more user-friendly. The final version of the tool was modified accordingly and was sent to seven experts in the field to examine its content validity. After the validation of the instrument, it was pilot tests by 10 participants who were excluded from the study. Scale reliability of the translated instrument was assessed using Cronbach’s alpha which revealed an acceptable value of 0.745.
Statistical Package for Social Science (SPSS), version 22, was used to compute and analyze the data. All responses provided by participants were entered into a personal computer. The accuracy of the data entered into SPSS was ensured by double-checking of 70 completed questionnaires (which were randomly selected), and the data entered into the computer were compared with the original data. The researchers also checked that all data fell within the accurate range for each item prior to data analysis. Two questionnaires were eliminated from the study because they had more than five missing items. Missing values were replaced with the means for each item.
Data analysis procedures included basic descriptive statistics to describe the sample. Means and standard deviations were computed for continuous variables. Frequencies and percentages were calculated for categorical variables. ANOVA and
Ethical approval was obtained from the Helsinki Committee (a research ethics committee) in the Gaza Strip. Furthermore; the Ministry of Health and the Palestinian Medical Relief Society provided the research team permissions to conduct the study at their primary healthcare centers. Each potential participant was approached by one of the data collectors who explained the purpose of the research to him/her. Then, each participant was asked to sign informed consent detailing the purpose of the study, the voluntary nature of participation, and the confidentiality of the information gathered from each one. It was explained to participants that refusing to participate or withdrawing from the study would not affect their treatment plan at the primary healthcare center.
A total of 689 questionnaires were collected, with only seven participants refusing to participate in the study. Of them, 41 questionnaires were eliminated (two had more than three missing variables, six did not mention for how long they had been diagnosed with hypertension, and 33 had been diagnosed with hypertension for a period of less than one year). The remaining 648 valid questionnaires were included in the analysis.
The age of participants ranged from 23 to 88 years with a mean of 59.0 (±11.49) years. Of them, 41.8% (
Sociodemographic characteristics of the participants.
Variable | Frequency | Percentage |
---|---|---|
Mean (minimum/maximum) | 59.0 (±11.49) years (23–88 years) | |
≤30 | 9 | 1.4 |
31–40 years | 31 | 4.9 |
41–50 years | 95 | 15.0 |
51–60 years | 234 | 36.9 |
61–70 years | 172 | 27.1 |
>70 years | 93 | 14.7 |
Males | 253 | 39.0 |
Females | 395 | 61.0 |
Married | 509 | 79.3 |
Single | 32 | 5.0 |
Widow | 83 | 12.9 |
Divorced | 18 | 2.8 |
None | 75 | 11.8 |
Primary | 107 | 16.8 |
Preparatory | 131 | 20.5 |
High school | 176 | 27.6 |
Diploma | 53 | 8.3 |
Bachelor | 89 | 13.9 |
Postgraduate studies | 7 | 1.1 |
Yes | 55 | 8.5 |
No | 542 | 83.8 |
Previous smoker | 50 | 7.7 |
Number of cigarettes | Range: (1–40) cigarettes/day | Mean: 13.9 (7.90) |
Age started smoking | Range: (10–49) years | Mean: 20.4 (7.26) |
Yes | 7 | 1.1 |
No | 625 | 96.6 |
Previous smoker | 15 | 2.3 |
Yes | 424 | 65.4 |
No | 224 | 34.6 |
1-2 times a week | 194 | 45.5 |
3-4 times a week | 101 | 23.7 |
5–7 times a week | 131 | 30.8 |
In 353 (39.0%) participants, duration of being diagnosed with hypertension was between 1 and 5 years, and 28.4% (
Medical history of participants.
Variable | Frequency | Percentage |
Range: 1–40 years | Mean: 9.77 (±7.48) | |
1–5 years | 253 | 39.0 |
6–10 years | 184 | 28.4 |
11–15 years | 94 | 14.5 |
≥16 years | 117 | 18.1 |
Yes | 395 | 61.5 |
No | 247 | 109 |
One | 301 | 38.5 |
Two | 87 | 74.7 |
Three or more | 15 | 21.6 |
Diabetes | 275 | 3.7 |
Heart disease | 123 | |
Other chronic diseases | 109 | |
One | 420 | 64.8 |
Two | 147 | 22.7 |
Three | 13 | 2.0 |
Missing (or do not know the name of their drugs) | 68 | 10.5 |
Amlodipine besylate | 299 | 54.56 |
Enalapril | 152 | 27.74 |
Losartan | 31 | 5.66 |
Bisoprolol | 106 | 19.34 |
Atenolol | 142 | 25.91 |
Co-Diovan (valsartan/hydrochlorothiazide) | 23 | 4.20 |
Valsartan | 51 | 9.31 |
Other medications | 51 | 9.31 |
Diuretics | 79 | 12.2 |
Low-dose aspirin | 127 | 22.7 |
Participants of this study showed highest adherence rates to the domain of medication adherence with a mean total score of 1.42 out of 4, while they were least adherent to diet with a mean total score of 2.18 (Table
Domains of the Hill-Bone Compliance to High Blood Pressure Therapy Scale.
No. of items | Minimum | Maximum | Mean of the total score | SD | Mean (total score/no. of items) | |
---|---|---|---|---|---|---|
Diet | 4 | 4.00 | 16.00 | 8.47 | 3.07 | 2.18 |
Appointment keeping | 2 | 2.00 | 8.00 | 3.6 | 1.69 | 1.8 |
Medication adherence | 9 | 9.00 | 31.00 | 12.82 | 3.90 | 1.42 |
Total score | 15 | 15.00 | 49.00 | 24.90 | 6.14 | 1.66 |
Hill-Bone Compliance to High Blood Pressure Therapy Scale responses.
Question: How often do you | Response rate (frequency/%) | Mean (SD) | |||
---|---|---|---|---|---|
None of the time | Some of the time | Most of the time | All of the time | ||
(1) Forget to take your HBP medicine? | 443 (68.5) | 132 (20.4) | 53 (8.2) | 19 (2.9) | 1.46 (0.77) |
(2) Decide not to take your HBP medicine? | 501 (77.7) | 102 (15.8) | 26 (4.0) | 16 (2.5) | 1.31 (0.67) |
(3) Eat salty food? | 232 (36.1) | 208 (32.4) | 117 (18.2) | 85 (13.2) | 2.09 (1.03) |
(4) Shake salt on your food before you eat it? | 169 (26.3) | 225 (35.0) | 146 (22.7) | 103 (16.0) | 2.28 (1.03) |
(5) Eat extra salty foods such as pickles and salty grounded red pepper? | 213 (33.2) | 271 (42.2) | 83 (12.9) | 75 (11.7) | 2.03 (0.96) |
(6) Eat fast food? (fat cook, chips, burgers) | 177 (27.4) | 302 (46.7) | 114 (17.6) | 53 (8.2) | 2.07 (0.88) |
(7) Get the next appointment before you leave the clinic? | 371 (57.6) | 77 (12.0) | 102 (15.8) | 94 (14.6) | 1.87 (1.14) |
(8) Miss scheduled appointments? | 378 (58.7) | 136 (21.1) | 54 (8.4) | 76 (11.8) | 1.73 (1.04) |
(9) Leave the dispensary without obtaining your prescribed pills? (due to long line, closure of clinic, forgot) | 394 (61.5) | 166 (25.9) | 45 (7.0) | 36 (5.6) | 1.57 (0.85) |
(10) Run out of blood pressure pills? | 282 (43.8) | 218 (33.9) | 78 (12.1) | 6 (10.2) | 1.89 (0.98) |
(11) Skip your blood pressure medicine 1–3 days before you go to the clinic? | 489 (75.9) | 106 (16.5) | 35 (5.4) | 14 (2.2) | 1.34 (0.68) |
(12) Miss taking your blood pressure pills when you feel better? | 495 (77.0) | 85 (13.2) | 32 (5.0) | 31 (4.8) | 1.38 (0.79) |
(13) Miss taking your blood pressure pills when you feel sick? | 497 (77.3) | 118 (18.4) | 13 (2.0) | 15 (2.3) | 1.29 (0.62) |
(14) Take someone else’s blood pressure pills? | 578 (89.6) | 40 (6.2) | 20 (3.1) | 7 (1.1) | 1.16 (0.51) |
(15) Miss taking your blood pressure pills when you care less? | 457 (70.7) | 121 (18.7) | 45 (7.0) | 23 (3.6) | 1.43 (0.77) |
In general, the great majority of participants (
Interestingly, the overall adherence scores on the Hill-Bone CHBPTS correlated significantly and in a negative direction with age (
Correlation of the total HILL-BONE CHBPTS score with variables of hypertensive patients.
Variables | Correlation ( | |
---|---|---|
Age | −0.201 | 0.0001 |
Duration of diagnosis with hypertension | −0.089 | 0.023 |
Number of comorbidities | 0.028 | 0.478 |
Number of antihypertensive drugs | −0.012 | 0.773 |
Impact of different variables on the level of participants’ adherence to the hypertension treatment regimen was measured by ANOVA and
Impact of demographic variables on compliance.
Mean | SD | ||
---|---|---|---|
Males | 24.94 | 6.37 | 0.899 |
Females | 24.87 | 6.0 | |
0.0001 | |||
≤30 | 30.49 | 10.35 | |
31–40 years | 27.56 | 7.49 | |
41–50 years | 26.10 | 6.59 | |
51–60 years | 25.25 | 5.94 | |
61–70 years | 23.48 | 5.30 | |
>70 years | 23.71 | 5.50 | |
None | 25.00 | 6.05 | 0.229 |
Primary | 25.67 | 6.91 | |
Preparatory | 25.16 | 5.50 | |
High school | 24.98 | 6.46 | |
Diploma | 24.24 | 6.40 | |
Bachelor | 23.66 | 5.32 | |
Postgraduate studies | 27.29 | 5.09 | |
0.996 | |||
Married | 24.89 | 6.22 | |
Single | 24.89 | 6.73 | |
Widow | 24.91 | 5.76 | |
Divorced | 25.26 | 5.87 | |
0.019 | |||
Yes | 27.46 | 7.91 | |
No | 24.82 | 5.91 | |
0.452 | |||
Yes | 25.03 | 6.01 | |
No | 24.64 | 6.39 | |
0.092 | |||
Yes | 24.87 | 6.07 | |
No | 24.96 | 6.31 | |
0.695 | |||
One | 25.09 | 5.94 | |
Two | 24.70 | 6.75 | |
Three | 25.92 | 4.62 |
Finally, the mean of the total score of the Hill-Bone CHBPTS and its subdomains was calculated according to the type of antihypertensive medication received by the participants (Table
Scores of the HILL-BONE CHBPTS and its subdomains according to the antihypertensive drug.
Diet | Appointment keeping | Medication adherence | Total score | |
---|---|---|---|---|
Amlodipine besylate | 8.40 (±3.40) | 3.62 (±1.68) | 12.65 (±3.85) | 24.66 (±5.98) |
Enalpril | 8.83 (±2.93) | 3.41 (±1.61) | 13.27 (±4.53) | 25.50 (±6.84) |
Losartan | 8.90 (±3.35) | 3.77 (±1.746) | 13.06 (±4.17) | 25.74 (±7.02) |
Bisoprolol | 8.65 (±3.00) | 3.75 (±1.52) | 12.85 (±4.1) | 25.25 (±5.94) |
Atenolol | 7.83 (±3.21) | 3.93 (±1.70) | 12.32 (±3.45) | 24.08 (±6.19) |
Co-Diovan | 8.41 (±3.26) | 4.32 (±1.62) | 12.75 (±3.99) | 25.48 (±5.62) |
Valsartan | 7.75 (±2.80) | 3.90 (±1.86) | 12.37 (±3.44) | 24.02 (±5.54) |
Other medications | 8.70 (±2.57) | 3.43 (±1.65) | 13.43 (±4.55) | 25.55 (±6.45) |
Since many participants received two or more antihypertensive drugs at the same time as shown in Table
Total score of the Hill-Bone CHBPTS according to the type of the antihypertensive drug.
Drug | Mean | SD | ||
---|---|---|---|---|
Amlodipine besylate | Yes | 24.66 | 5.98 | 0.352 |
No | 25.11 | 6.27 | ||
Enalpril | Yes | 25.50 | 6.84 | 0.201 |
No | 24.71 | 5.91 | ||
Losartan | Yes | 25.74 | 7.02 | 0.436 |
No | 24.86 | 6.10 | ||
Bisoprolol | Yes | 25.25 | 5.94 | 0.507 |
No | 24.83 | 6.18 | ||
Atenolol | Yes | 24.08 | 6.19 | 0.378 |
No | 24.96 | 6.14 | ||
Co-Diovan | Yes | 25.48 | 5.62 | 0.627 |
No | 24.88 | 0.25 | ||
Valsartan | Yes | 24.02 | 5.54 | 0.247 |
No | 24.97 | 6.19 | ||
Other medications | Yes | 25.55 | 6.45 | 0.477 |
No | 24.85 | 6.12 |
Barriers to adherence to hypertension therapy reported by participants are listed by decreasing strength in Table
Reported barriers to adherence to hypertension therapy.
Barrier | Mean | SD |
---|---|---|
(1) I am unable to do exercise | 2.716 | 1.774 |
(2) I like fast and fried food | 2.567 | 1.440 |
(3) I like salty foods (I cannot keep myself away from salty foods) | 2.434 | 1.520 |
(4) In general, I do not like medications | 2.423 | 1.517 |
(5) My medication is too expensive | 2.370 | 1.540 |
(6) I have to take too many medications every day | 2.346 | 1.525 |
(7) My medication is not available | 2.095 | 1.454 |
(8) I experience side effects from medication | 2.088 | 1.416 |
(9) I have no time for regular exercise in my life | 2.017 | 1.537 |
(10) Lack of motivation as there is no cure | 2.013 | 1.392 |
(11) I am not interested in doing exercise | 2.002 | 1.529 |
(12) I find it difficult to follow my treatment regime | 1.997 | 1.252 |
(13) I forget to take my medication | 1.956 | 1.338 |
(14) I do not want to take my medication | 1.953 | 1.347 |
(15) I am not able to go to the clinic to get my medication | 1.911 | 1.586 |
(16) I am not interested in stopping smoking | 0.363 | 1.110 |
(17) I would like to stop smoking, but find it difficult | 0.362 | 1.082 |
The results of our study revealed that the overall adherence to hypertension treatment regimens was moderate to good with a score of 1.66, when one represents the best possible adherence rate, while four represents the worst. The rates of adherence to antihypertensive medications and appointment keeping were moderate to good with scores of 1.42 and 1.8, respectively. Participants had more difficulty with their adherence to dietary advice, such as reducing salty foods, with a score of 2.14, representing poor-to-moderate adherence. The overall adherence to the management of hypertension was found to get better with older age as well as increasing duration since the diagnosis of hypertension was first made. However, no impact on adherence scores was found to be exerted by comorbidities or number of antihypertensive agents. Interestingly, smokers showed significantly better adherence to medications than nonsmokers. From the 17 examined barriers to good adherence to antihypertensive treatment regimens, all were rated <3 from a maximum of 4, representing a moderate-to-weak strength of feeling about them. However, among the highest rated barriers to follow recommended treatment regimens were difficulties with resisting certain food choices, such as fried or salty foods, as already identified in the difficulty of adherence to the domain of dietary management, as well as inability to do regular exercise.
Adherence to management regimens of hypertension remains a global challenge with rates of adherence around 30%–50% in low-income countries and 50%–72% in high-income countries [
As in numerous other studies, this study found adherence to lifestyle and dietary recommendations to be a greater challenge than adherence to taking medication [
A multitude of studies have examined potential factors affecting medication adherence and found that sociodemographic factors are poor determinants of adherence with very little consistency in findings [
Medication adherence is a dynamic process and can vary in individuals as well as populations, possibly increasing around clinic visits in individuals or decreasing with disease duration [
Another important factor influencing the effectiveness of interventions to improve the level of adherence to treatment regimens is the context in which they are applied, and their effectiveness varies from one setting to another and from one individual to another [
The Hill-Bone Compliance to High Blood Pressure Therapy Scale is a specific tool to address treatment for hypertension and has been validated in many languages, but this Arabic translation had not been validated before. Self-reporting of adherence to treatment regimens is prone to underestimation of the problem, and employing a second objective measurement of adherence could have made results more accurate and reliable. Furthermore, actual blood pressure control has not been measured in this study to see how adherence correlates with blood pressure control.
The sample of this study was a convenience sample, which might limit its generalizability. Due to the geopolitical isolation of the Gaza Strip, participants had been recruited from the Gaza Strip only; however, participants came from all geographical regions within the territory. Thus, while this study is representative of the local population and might add important points for low-income settings, it might not always be generalizable to different high-income settings.
Overall adherence to antihypertensive medication was surprisingly good in patients with a diagnosis of hypertension for over one year. However, adherence to lifestyle advice or dietary regimes remains poor. A combination of interventions using low-cost mobile technology, combined with face-to-face interventions by healthcare professionals, can be applied to improve this further. Monitoring and documentation of any interventions are essential to evaluate potential success or failure of such interventions and apply such lessons in the future.
The data used to support the findings of this study are available from the corresponding author upon request.
The authors of this study declare no conflicts of interest.
The research team would like to thank all staff at the Palestinian Health Ministry and all staff at the primary healthcare centers involved in this study for their help to support this study. The research team is very grateful to the Palestinian Medical Relief Society for their general support to cover the expenses for this research study.