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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 6, November/December 2017

AFRICA

351

The exact prevalence rate of medication non-adherence among

cardiac patients in Sudan is not known since there are limited

published studies. A study was conducted at Elshaab Hospital in

Khartoum to determine the adherence to secondary-prevention

medication among 210 patients and it was found to be 66%.

15

Another study was performed among 76 patients with heart failure

admitted to the Sudan Heart Institute in Khartoum, which indicated

that 75% of the respondents were adherent to their medications.

16

These previous studies have used limited study populations

or a small number of patients in single clinical settings and may

not enable meaningful conclusions to be drawn regarding levels

of adherence to cardiovascular medications. This highlights the

need to expand this area of research to include patients attending

multicentre, out-patient cardiovascular clinics and to improve the

quality of such research. Therefore, this study was conducted to

evaluate prevalence, predictors and barriers of non-adherence to

medications among cardiac patients attending the three largest

national referral cardiac centres located in Khartoum State.

Methods

This was a descriptive, quantitative and cross-sectional study

designed to describe the adherence of patients with cardiovascular

diseases to their medications.

Sudan is one of largest countries in Africa (total area of

1 861 484 km

2

) with an estimated population of 36 million people

as of July 2015 (CIA fact book, 2016). It is a federal nation

consisting of 18 states. Khartoum State, the capital of Sudan,

covers an area of 28 165 km

2

and contains almost 20% of the

population, 84% of whom live in urban areas.

This study was conducted between September 2014 and

March 2015 in Khartoum State, Sudan. The study population

consisted of out-patients attending the cardiac clinics in Ahmed

Gasim Cardiac Surgery and Renal Transplantation Centre,

Elshaab Teaching Hospital and Sudan Heart Institute, because

they represent the three largest national referral cardiac centres

located in Khartoum State.

The study was conducted in accordance with the Declaration

of Helsinki and national and institutional standards. Ethical

approval for this study was obtained from the Directorate

of Research, Ministry of Health, Khartoum State. Inclusion

criteria for a patient to enter the study were patients aged 18

years or older diagnosed with cardiovascular disease or its major

risk factor, hypertension, who started using a cardiovascular

medication for a duration of three months or more. Patients who

had psychiatric disorders or cognitive impairment were excluded.

The sample size was determined using PS power and sample

size calculator V.3.05.

17

A sample of 260 patients would be

necessary to determine a 20% difference in proportion between

two groups; for example, male versus female with 90% power

and at 5% significance level. Assuming a response rate of 60%, a

sample size of 433 patients was approached to be included in the

study. The total number of patients selected from each hospital

was proportional to the out-patient population attending the

hospital per year. The patients at each hospital were randomly

selected, using systematic random sampling from the patients’

registration lists.

The content validity of the study questionnaire was

established by a research group at Kuwait University. The

questionnaire was translated into Arabic and subjected to a

process of forward and backward translation. The accuracy and

meaning of the translated versions both forward and backward

were checked, and recommended amendments where necessary

were discussed before being finalised. It was pre-tested for

content, design, readability and comprehension on 16 patients

with cardiovascular diseases, and modifications were made as

necessary so that the questionnaire was simple to understand

and answer, yet gave accurate data.

The final version of the pre-tested questionnaire was

composed of four sections, and it contained both open-ended

and closed questions. The first section included items to provide

information about the sociodemographic characteristics of

the respondents (age, gender, marital status, educational level,

residence and monthly income). Section two consisted of

questions to provide information about the clinical variables

of the study population (type and duration of cardiovascular

disease, and type and duration of medications used by the

patient).

The third section evaluated adherence to medications using

the validated eight-item Morisky medication adherence scale

(MMAS-8).

18

Each item measures a specific medication-taking

behaviour; response categories are yes/no for each item with a

dichotomous response and a five-point Likert response for the

last item (never/rarely, once in a while, sometimes, usually and all

the time). The negative response for each item was coded as one,

except for the item asking if the patient took the medications

yesterday (where a positive response was coded as one). The

total score was calculated by summing the values from all

eight question items. Optimal adherence was defined as having

a MMAS-8 score of greater than six out of a total of eight,

according to the methodology used in previous literature.

19,20

Section four included questions to explore the reasons for not

taking the medications regularly.

Data were collected via structured face-to-face interviews of

the respondents in the waiting rooms of the cardiac clinics using

the pre-tested questionnaire. The interview lasted approximately

15–20 minutes. The selected patients were contacted and given

an explanation about the purposes of the research. They were

assured of confidentiality and gave verbal consent to participate

in the study. Data about clinical variables were checked with the

attending physicians from the patients’ medical records.

Statistical analysis

Data were entered into the Statistical Package for Social Sciences

[IBM SPSS Statistics for Windows, version 23 (IBM Corp,

Armonk, NY, USA)] and descriptive analysis was conducted.

The results were reported as percentage (95% confidence

interval) and mean (standard deviation). Univariate logistic

regression was performed to determine the relationship of each

independent variable with adherence to cardiac medications. All

variables with

p

0.25 in the univariate analysis were included

in the multiple logistic regression analysis to determine the

factors that were independently associated with non-adherence

to cardiac medications. The excluded variables were gender (

p

=

0.38), marital status (

p

=

0.83), residence (

p

=

0.36), hospitals (

p

=

0.57) and duration of medication use (

p

=

0.45). Only the results

of multivariate logistic analysis are reported showing odds ratio

(OR) and 95% confidence interval (CI). Statistical significance

was accepted at

p

<

0.05.