CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 4, May 2013
126
AFRICA
come to the clinic on any other appropriate time for follow-up
care.
For those patients who had lost the benzathine prophylaxis
card, we relied on self-reports as to how many injections he/
she had received over the previous six months. The proportion
of these patients, together with those from whom information
was obtained over the phone was catered for during analysis.
At six months of follow up, a separate structured, pre-coded
questionnaire was administered to those patients without 100%
adherence, with the aim of capturing the factors or reasons for
missing the benzathine prophylaxis injections.
Measuring benzathine penicillin injection delivery
9
was
calculated as a percentage of the number of injections received,
divided by the number prescribed and multiplied by 100.
Receiving less than 80% of injections places an individual at a
higher risk of recurrent ARF.
9
Statistical analysis
Data were entered in Epidata 3.1, backed and cleaned to prevent
data loss and then exported to STATA version 10.0. Continuous
variables were summarised in means (standard deviation) and
median (interquartile range). Categorical data were summarised
using frequency and percentages and results are presented in
tables. To address the first objective, the adherence rates for
RHD patients attending Mulago Hospital were calculated as
follows:
The number of injections required in six months for a patient
on four-weekly benzathine prophylaxis
=
six injections.
Adherence rates for individual patients was calculated as:
no of injections received
___________________
no of injections expected
×
100%
We then proceeded to determine the level of adherence, the mean
adherence rate and median.
For the second objective, bivariate analysis was done with a
confidence interval of 95%, and Pearson’s chi-square test was
used to ascertain statistical significance. Variables included in the
bivariate analysis included age, gender, patient’s home address,
level of education, patient’s employment status, the NYHA class,
tribe, and history of previous use of benzathine penicillin (all
variables were put in two categories). Fisher’s exact test was used
where cells had less than five readings. A
p-
value
<
0.05 was
considered significant. To ascertain for statistical significance
(
p
<
0.05) between subjective and objective assessment for
adherence, the Pearson’s chi-square test was used.
Results
From June 2011 to March 2012, out of the 112 patients screened
for eligibility, 95 rheumatic heart disease patients were recruited
and followed up for a period of six months to assess their
adherence levels and associated factors (Fig. 1). Reasons for
excluding the 17 patients included: six patients with probable
RHD, four patients with congenital heart disease, four with
mitral valve prolapse and three declined to consent. Out of these
95 patients, 82 (86.3%) completed the six-month follow-up
period; 13 (13.7%) did not complete six months of follow up
because 10 had died and three were lost to follow up. Of the 82
patients who completed follow up, 71 (86.6%) were objectively
assessed for adherence levels using the benzathine penicillin
card provided at the beginning of the study and 11 (13.4%) were
subjectively assessed using self-reporting. Of the 11 patients, six
came to hospital at follow up but had lost their cards and five
were followed up over the phone.
Table 1 shows the baseline characteristics of the patients. The
majority was female (75, 78.9%). The patients’ ages ranged from
TABLE 1. BASELINE CHARACTERISTICS OF THE PATIENT
Variable
Frequency
(
n
=
95)
Percentage
(%)
Age
<
18 years
22
23.2
≥18
years
73
76.8
Patients’ home
Rural
38
40.0
Town/city
57
60.0
Gender
Female
75
78.9
Male
20
21.1
Level of education
College
10
10.5
Secondary
29
30.5
Vocational
4
4.2
Primary
44
46.3
None
8
8.4
Employment status
Unemployed
65
68.4
Employed
30
31.6
NYHA class
I
7
7.4
II
39
41.1
III
32
33.7
IV
17
17.9
Tribe
Ganda
49
51.6
Soga
4
4.2
Toro
2
2.1
Ankole
9
9.5
Nyoro
2
2.1
Acholi
3
3.2
Others
26
27.4
Adherence rate
≥
80%
54%
Adherence rate
<
80%
46%
Fig. 2. Overall levels of adherence to monthly benzathine
penicillin prophylaxis.
