Memoire Online - An assessment of adherence to antihypertensive treatment and associated factors in patients at the Yaounde general hospital

This study was conducted at the external consultation service of the cardiology unit of the Yaounde General Hospital (YGH) which is located in Yaounde, the capital city of Cameroon.YGH serves as a teaching centre, and is a reference hospital for other hospitals in the Centre region.

YGH is a state-owned hospital made up of several units: internal medicine, surgery, obstetrics, gynaecology and paediatrics. It covers an area of 20,301 square metres and as of 2001 had 302 beds. Inhabitants from Yaounde and beyond come to this reference health institution to seek for general and specialized health services.

This study was carried out over a period of seven months (November 2017 - May 2018).

Hypertensive patients receivingantihypertensive treatment as outpatients at the YGH.

Ø Outpatients diagnosed with HBP and on antihypertensive drug treatment for at least 6 months prior to recruitment period;

The following assumptions were made:previous data indicated an adherence rate of 12.9% in Garoua[16]. So proportion was taken as 12.9%(p = 0.129), 95% confidence interval, and 5% margin of error(d = 0.05).

Therefore, from the above formula a minimum sample size of 173 patients was required for the study.

Ø A laptop with Microsoft^®Office Tools 2013 for data entry and Epi-info^TMsoftware Version 3.5.4 for data analysis.

In accordance with research ethics, ethical clearance was obtained from the Institutional Review Board of the Faculty of Medicine and Biomedical Sciences of the University of Yaounde I(APPENDIX 1A), as well as authorization from the Director of the YGH before the recruitment of patients for the study (APPENDIX 1B). The study was explained to the patients and informed consent by signature was obtained prior to their enrolment into the study (APPENDIX 2). During the study, the case report forms (APPENDIX 3) were kept secret by the investigator from people not involved in the study, in order to respect patient confidentiality.

The patients admitted into this study were selected consecutively at the external consultation service of the cardiology unit. Patients that met our inclusion criteria were selected during consultations and interviewed immediately after. After obtaining their written consent, we proceeded by measuring their resting BP. Two sitting BP measurements were taken on both arms with a pretested electronic sphygmomanometer approximately 2 minutes apart. Another 2 minutes later, a third measurement was taken on the arm with the highest BP reading. Then an average of the last two readings was eventually used to determine the BP level during the visit. After recording the BP reading, we proceeded with an interview of the patients in order to fill the pretested questionnaires. BP measurements and interview were carried out in private in a consultation box. The 2014 Evidence-Based Guideline for the Management of High Blood Pressure in Adults[113] was used to evaluate the level of control of patient BP:

v Hypertensive patients aged 60 years and above were considered to have a controlled hypertension if their average BP reading was<150/90 mmHgduring the last 3 months and if they presented with no diabetes nor chronic kidney disease.

v Hypertensive patients aged 60 years and above were equally considered to have a controlled hypertension if their average BP reading was<140/90 mmHg during the last 3 monthsif they presented with diabetes or chronic kidney disease.

v Also, patients aged under 60 were considered to have a controlled hypertension if their average BP reading was<140/90 mmHgduring the last 3 months and if they presented with or without other comorbidities (diabetes and chronic kidney disease).

Ø Sociodemographic data (independent variables): Age, sex, zone of residence, marital status, trip duration to the hospital, level of education, and profession.

Ø Socioeconomic data (independent variables):Socioeconomic status (which is an adapted classification from theRevised Kuppuswamy's socio-economic status scale- January 2015[114](see APPENDIX 3) where the projected family income was estimated from the Gross National Income (GNI) per capital; health insurance; monthly drug costs. A score of <5 was considered low; between 5 and 10 was considered middle; and >10 was considered high socioeconomic status.

Ø Clinical characteristics of respondents(independent variables):Comorbidities present (if any); blood pressure readings; handicap present (if any).

Classification of BP:SBP <120mmHg and DBP <80mmHg was considered optimal; SBP [120-129]mmHg and/or DBP [80-84]mmHg was considered normal; SBP [130-139]mmHg and/or DBP [85-89]mmHg was considered High Normal; SBP [140-159]mmHg and/or DBP [90-99]mmHg was considered Grade I hypertension; SBP [160-179]mmHg and/or DBP [100-109]mmHg was considered Grade II hypertension; SBP=180mmHg and/or DBP =110mmHg was considered Grade III hypertension; SBP =140mmHg and DBP <90mmHg was considered isolated systolic hypertension.

Definition of heart failure:Inability of the heart to ensure blood flow necessary for the metabolic and functional needs of body organs. Clinical signs include edema, tachycardia, and rales with low ejection fraction (EF<43%).

Diagnostic criteria for diabetes: A1C =6.5% or Fasting Plasma Glucose =126 mg/dl (7.0 mmol/l) or 2-h plasma glucose =200 mg/dl (11.1 mmol/l) during an Oral Glucose Tolerance Test or in a patient with classic symptoms of hyperglycemia or hyperglycemic crisis, a random plasma glucose =200 mg/dl (11.1 mmol/l).

Definition of gout:Inflammatory microcrystalline arthropathy associated with intense pain and related to a disruption of the metabolism ofuric acid.Hyperuricemia is generally above 390 umol/L (6.5 mg/dL).

Diagnostic criteria for arthritis:Prolonged morning stiffness, swollen joints, and painful/inflamed joints.

Diagnostic criteria for gastritis: Nausea, abdominal pain, bloating, vomiting, indigestion, and burning feeling in the epigastric region.

Diagnostic criteria for hyperthyroidism: Nervousness, mood swings, muscle weakness, heat intolerance, insomnia, hand tremors, tachycardia, diarrhea, weight loss, enlarged thyroid gland, and elevated thyroid stimulating hormone, free thyroxine and total triiodothyronine levels.

Definition of epilepsy: Presence or history of recurrent convulsions which are involuntary, violent, and spasmodic or prolonged contraction of skeletal muscles.

Definition of anemia: Decrease in hemoglobin per unit of blood volume below physiological values i.e. 13 g / dL in men; 12 g / dL in women and children.

Diagnostic criteria for benign prostate hypertrophy: Presence of enlarged prostate, high prostate specific antigen levels, polyuria, weak stream and/or urinary incontinence.

Diagnostic criteria for depression: Presence of psychological symptoms (low mood, low self-esteem, feeling irritable, no interest in things, anxiety, suicidal thoughts); and physical symptoms (changes in weight, constipation, unexplained pains, loss of libido, changes in menstrual cycle).

Definition of glaucoma: Intraocular pressure above an upper normal value of 21 mmHg.

Diagnostic criteria for hemorrhoids: Presence of bleeding with or without defecation, mucous discharge, pruritus, incomplete evacuation, distal rectal mass upon digital exam, and presence of fissures after anoscopy.

Diagnostic criteria for deep venous thrombosis: Presence of pain, swelling and tenderness in legs, warm skin in the area of the clot upon palpation, positive D-dimer test, detection of clots with Doppler ultrasound.

Definition of physical handicap: Presence of physical defects, including upper or lower limb loss or poor manual dexterity.

Definition of sensory handicap: Presence of visual impairment or blindness, hearing loss or deafness.

Ø Therapeutic characteristics of respondents(independent variables): Type of therapy; molecule(s) prescribed;Drugs prescribed (pioneer or generic); Antihypertensive drug groups prescribed; number of drugs used per day; Dosage schedule; Presence of side effects (if any); Duration onantihypertensive treatment.

Ø Adherence profile (dependent variable):The Eight-Item Medication Adherence Scale (Table VI) was used to assess therapeutic adherence[95].

We assessed the adherence level of the study population by using the validated MMAS-8. The scale is based on patients` self-response.Patients with a score of 8 on the scale were termed highly adherent, medium adherers were those with a score of 6 to <8, and those classified as lowadherers were those with a score of <6.This medication adherence scale has the advantage of beingrelatively simple and practical to use in clinical settings. The instrument was used to identify patients with adherence problems, and could also be used to monitor adherence over the course of the treatment. One important feature of the scale is that treatment-related attitudinal and behavioral problems thatthe patient may be facing can be immediately identified and health care providers may provide reinforcement and advice such that the patient can take positive steps early on to address these issues. Patients were considered to have a poor adherence if they had <8 and good adherence if they scored 8 on the MMAS-8 (Table VII).

Data concerning patients' knowledge of hypertension (i.e. causes, treatment, and complications) was also collected on the pretested questionnaires (APPENDIX 3). Knowledge scores for individuals were calculated and summed up to give a total knowledge score. The scoring range isfrom 0 (minimum) to 16 (maximum). A cut-off score of <8 was considered as poor knowledge, ascore of [8-12] was considered knowledgeable and a score of [13-16] was considered good knowledge.

ITEM	CORRECTED ITEM-TO-TOTAL CORRELATION
1. Do you sometimes forget to take your high blood pressure pills?	.4639
2. Over the past 2 weeks, were there any days when you did not take your high blood pressure medicine?	.5108
3. Have you ever cut back or stopped taking your medication without telling your doctor because you felt worse when you took it?	.4277
4. When you travel or leave home, do you sometimes forget to bring along your medications?	.4095
5. Did you take your high blood pressure medicine yesterday?	.3038
6. When you feel like your blood pressure is under control, do you sometimes stop taking your medicine?	.5044
7. Taking medication everyday is a real inconvenience for some people. Do you ever feel hassled about sticking to your blood pressure treatment plan?	.4009
8. How often do you have difficulty remembering to take all your blood pressure medication?	.5896
á Reliability, .83.

Cut-off score	Adherence status
8	High adherers	Good adherence

[6-8[	Medium adherers	Poor adherence
<6	Low adherers

Data entry and analysis was undertaken using the statistical software Epi Info version 3.5.4. Data cleaning was performed to check for accuracy, consistency and that there were no missed values during entry. Frequencies, proportions and summary statistics were equally generated to describe the study population in relation to the relevant variables.Bivariate analysis using the chi2test was carried out to assess associations of each independent variable with thedependent variable. Variables with P-value< 0.05 in bivariate analysis were selected as candidate variables for multivariate analysis with logistic regression. Odds ratio and 95% confidence interval were used to identify the presence andstrength of association. Statistical significance was considered at P-value < 0.05.

An assessment of adherence to antihypertensive treatment and associated factors in patients at the Yaounde general hospital

CHAPTER III: MATERIALS AND METHOD