25 / 62
CARDIOVASCULAR JOURNAL OF AFRICA • Volume 31, No 4, July/August 2020
AFRICA
187
Since the most common cause of valvular heart diseases in our
setting is rheumatic heart disease, our participants were young
and predominantly female.
2,32,33
The mean age of participants
in the large Swedish cohort of patients with MHVs was 63
years, older than in our study.
15
Old age and the high burden
of co-morbid conditions most likely predisposed the Swedish
patients to bleeding than in our young population. Given the
young age of our cohort, the reported rate of bleeding events
was high and should call for vigilant monitoring of our patients.
We also observed that the risk of bleeding was incremental with
longer duration of warfarin use.
Similar to a previous study in our clinic, the majority of our
participants had sub-optimal anticoagulation control.
17
As a
result, individuals with a longer duration of warfarin use in our
setting are more likely to be exposed to prolonged periods of
sub-optimal anticoagulation control than those with a shorter
duration. Hence, there is an incremental increase in bleeding risk
with a longer duration of warfarin use. Decentralisation of INR
testing centres and emphasis on patient education are necessary
steps for the achievement of anticoagulation control.
33,34
Table 1. Baseline characteristics of enrolled patients
with MHVs at PMH, Gaborone (
n
= 142)
Characteristics
All patients (
n
= 142)
Gender,
n
(%)
Female
97 (68.3)
Male
45 (31.7)
Mean age (SD), years
42 (12)
Age groups (years),
n
(%)
≤ 30
28 (19.7)
31–50
72 (50.7)
> 50
42 (29.6)
Residence,
n
(%)
Gaborone
80 (56.3)
Outside Gaborone
62 (43.7)
Level of education,
n
(%)
No formal schooling
13 (9.2)
Primary school
29 (20.4)
Secondary school
66 (46.5)
University/college
34 (23.9))
Marital status,
n
(%)
Not married
106 (74.6)
Currently married
36 (25.4)
Monthly income,
n
(%)
No income
63 (44.4)
< 1 000 Pula
14 (9.9)
1 000–4 000 Pula
38 (26.7)
> 4 000 Pula
27 (19.0)
Employment,
n
(%)
Employed
77 (58.0)
Unemployed
61 (42.0)
Co-morbidities,
n
(%)
Hypertension
40 (30.3)
Atrial fibrillation
30 (21.1)
HIV
25 (17.1)
Heart failure
21 (14.8)
Diabetes mellitus
2 (1.4)
Valves operated,
n
(%)
Mitral
73 (66.4)
Aortic
26 (23.6)
Tricuspid
2 (1.8)
Dual (mitral/aortic)
7 (6.4)
Triple (mitral/aortic/tricuspid)
2 (1.8)
One Botswana Pula was equivalent to 0.09757 American dollars during the time
of study.
PMH, Princess Marina Hospital; HIV, human immunodeficiency virus; SD,
standard deviation.
Table 2. Difference in bleeding and thromboembolic complications by
gender among patients with MHVs at PMH, Gaborone (
n
= 142)
Complications
All
(
n
= 142)
Male
(
n
= 45)
Female
(
n
= 97)
p
-value
Major bleeding complications,
n
(%) 20 (14.1) 8 (17.8) 12 (13.4) 0.389
Intracranial bleeding
3 (15)
2 (25.0)
1 (8.3) 0.537
Intra-ocular
1 (5)
0
1 (8.3) 1.000
Gastrointestinal
10 (50)
4 (50.0)
6 (50.0) 1.000
Haematuria/menorrhagia/epistaxis 6 (30)
2 (25.0)
4 (33.4) 1.000
Thrombotic complications,
n
(%)
32 (22.5) 10 (31.2) 22 (68.8) 0.711
Stroke/TIA
25 (78.1) 7 (70.0) 18 (81.8) 0.662
Valve thrombosis
7 (21.9)
3 (30.0)
4 (18.2) 0.580
PMH, Princess Marina Hospital; TIA, transient ischaemic attack; MHVs,
mechanical heart valves.
Table 3. Factors associated with bleeding and thromboembolic
complication rates of patients with MHVs on warfarin
Characteristics
Thromboembolic
p
-value
Major bleeding
p
-value
No
(
n
= 110)
Yes
(
n
= 32)
No
(
n
= 122)
Yes
(
n
= 20)
Age, mean (SD),
years
43.1
(12.9)
41.0
(11.9)
0.59 43.3
(12.7)
39 (11.9) 0.04
Valve duration,
median (IQR), years
3
(1.0–7.0)
8.5
(2.3–15.8) 0.01 5 (3–11) 3 (1.6–7) 0.08
TTR, median (IQR),
years
30.2
(14.0-54.0)
25.6
(14.3–39.1)
0.26 30.1
(15–49)
20.5
(13.3–55.2)
0.50
Residence,
n
(%)
Gaborone
57 (51.8) 23 (71.9)
0.04 70 (57.4) 10 (50.0) 0.54
Outside Gaborone 53 (48.2)
9 (28.1)
52 (42.6) 10 (50.0)
Education,
n
(%)
No formal
education
11 (10.0)
2 (6.3)
0.048 11 (9.0)
2 (10.0) 0.87
Primary school
26 (23.6)
3 (9.4)
26 (21.3) 3 (15.0)
Secondary school
52 (47.3) 14 (43.8)
57 (46.7) 9 (45.0)
University/college 21 (19.1) 13 (40.6)
28 (23.0) 6 (30.0)
Marital status,
n
(%)
Not married
80 (72.7) 26 (81.3)
0.33 91 (74.6) 15 (75) 0.97
Currently married 30 (27.3)
6 (18.7)
31 (25.4)
5 (25)
Monthly income,
n
(%)
No income
51 (46.4) 12 (37.5)
0.51 58 (47.5) 5 (25.0) 0.10
< 1 000 Pula
11 (10)
3 (9.4)
13 (10.7) 1 (5.00)
1 000–4 000 Pula 30 (27.3)
8 (25.0)
31 (25.4) 7 (35.0)
> 4 000 Pula
18 (16.4)
9 (28.1)
20 (16.4) 7 (35.0)
Current smoker,
n
(%)
3 (2.7)
2 (6.3)
0.34 5 (4.1)
0
0.36
Alcohol intake,
n
(%) 6 (5.5)
5 (15.6)
0.06 9 (7.4)
2 (10.0) 0.68
HIV positive,
n
(%) 20 (18.2)
2 (6.3)
0.73 25 (20.5)
0
0.03
Valve operated,
n
(%)
Mitral
73 (66.4) 21 (65.6)
0.83 83 (68.0) 11 (55.0) 0.004
Aortic
26 (23.60 8 (25.0)
30 (24.6) 4 (20.0)
Tricuspid
2 (1.80)
0
1 (0.8)
1 (5.0)
Dual (mitral/
aortic)
7 (6.4)
3 (9.0)
8 (6.6)
2 (10.0)
Triple (mitral/
aortic/tricuspid)
2 (1.8)
0
0
2 (10.0)
One Botswana Pula was equivalent to 0.09757 American dollars during the time of
study.
IQR, interquartile range; SD, standard deviation; MHVs, mechanical heart valves.