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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 3, May/June 2018
142
AFRICA
patients with valvular AF and 13 among those with non-valvular
AF.
A total of 70 patients, among them two with valvular AF and
10 with non-valvular AF, were lost to follow up within six months
but were included in estimated rates as censored observations.
Four patients with valvular AF and 11 with non-valvular AF
were rehospitalised within 60 days; 16 patients in each group
were either rehospitalised or had died by day 60. The unadjusted
risk of 180-day mortality rate in patients with valvular AF was
twice that in patients with non-valvular AF [hazard ratio (HR)
2.11, 95% CI: 1.05–4.24,
p
=
0.032], while the unadjusted risks
of 60-day rehospitalisation did not differ significantly. Without
adjustment for potential confounding factors, neither valvular
nor non-valvular AF was associated with 60-day readmission,
while valvular but not non-valvular AF was associated with
180-day all-cause mortality (Table 5).
Adjustment for clinical characteristics found to be prognostic
of the outcomes
13
and therefore possible confounders had little
effect on these estimated associations. Valvular AF was not a
significant predictor of all-cause death or readmission within
60 days (Fig. 1) (HR 1.39, 95% CI: 0.80–2.42,
p
=
0.24) but
was associated with all-cause death within 180 days (HR 1.61,
95% CI: 0.99–2.62,
p
=
0.056) (Fig. 2). On the other hand,
non-valvular AF was not a significant predictor of either
all-cause death or readmission within 60 days (HR 0.99, 95%
CI: 0.58–1.68,
p
=
0.96) (Fig. 1) or the outcome all-cause death
within 180 days (HR 0.70, 95% CI: 0.39–1.26,
p
=
0.23) (Fig. 2).
Discussion
We found AF to be present in 20.8% of AHF patients. Forty-
four per cent of the patients with AF had valvular heart disease.
Sixty-one per cent of the patients with non-valvular AF had
hypertension. The presence of AF was not associated with the
primary endpoints, but having valvular AF predicted death
within 180 days.
To the best of our knowledge, this is the first sub-Saharan
African study to assess the prevalence and clinical characteristics
Table 2. Baseline patient clinical characteristics
versus valvular and non-valvular AF
Variables
Valvular AF
1
(
n
=
92)
Non-valvular AF
1
(
n
=
115)
p
-value
2
Age (years)
52.2 (18.98),
52.0 (38.5–65.5)
60.8 (15.74),
64.0 (53.0–72.0)
0.0005
Gender: female,
n
(%)
59 (64.1)
60 (52.2)
0.0838
Black African,
n
(%)
91 (98.9)
111 (97.4)
0.4245
BMI (kg/m
2
)
24.89 (6.482),
24.76 (20.91–27.91)
24.90 (5.005),
24.52 (21.23–28.11)
0.7187
SBP (mmHg)
119.9 (24.39),
112.0 (100.0–133.0)
127.9 (33.38),
124.5 (108.0–150.0)
0.0699
DBP (mmHg)
78.4 (17.01),
79.0 (65.0–90.0)
82.2 (21.29),
80.0 (68.0–94.0)
0.2521
Heart rate
111.7 (29.68),
109.0 (92.0–127.0)
107.4 (26.86),
107.0 (90.0–120.0)
0.4319
History of
hypertension,
n
(%)
38 (41.8)
70 (60.9)
0.0064
Hyperlipidaemia,
n
(%)
4 (4.6)
4 (3.6)
0.7244
Stroke,
n
(%)
3 (3.3)
3 (2.6)
0.7706
Ischaemic heart
disease,
n
(%)
4 (4.3)
6 (5.2)
0.7719
Valvular disease,
n
(%)
92 (100.0)
0 (0.0)
< 0.0001
Peripheral vascular
disease,
n
(%)
2 (2.2)
1 (0.9)
0.4235
Anaemia,
n
(%)
46 (51.7)
51 (45.9)
0.4196
Pericardial disease,
n
(%)
3 (3.3)
6 (5.2)
0.5030
Cardiomyopathy,
n
(%)
29 (32.2)
50 (43.5)
0.1003
LVEF (%)
47.21 (14.440),
46.00 (40.00–58.00)
38.20 (15.506),
36.50 (27.00–45.70) < 0.0001
LVEF < 40%,
n
(%)
22 (24.7)
59 (55.7)
< 0.0001
eGFR
(ml/min/1.73 m
2
)
78.731 (39.738),
74.123 (48.772–92.796)
77.676 (40.914),
69.039 (49.709–100.88)
0.7990
Renal dysfunction,
n
(%)
4 (4.3)
6 (5.6)
0.6961
1
Mean (SD), median (first quartile – third quartile) for a continuous variable and
frequency (per cent) for a categorical variable.
1
Chi-squared
test
for a
categorical variable, CMH
for an ordinal variable and
Wilcoxon
test
for a
continuous variable.
BMI, body mass index; SBP, systolic blood pressure; DBP, diastolic blood pres-
sure; LVEF, left ventricular ejection fraction; eGFR, estimated glomerular filtra-
tion rate.
Table 3. Anticoagulation and aspirin use versus time
Parameters
1 month prior
to admission Admission
Day 30
6 months
Atrial fibrillation (
n
=
209)
Anticoagula-
tion,
n
(%)
16/136 (11.8) 107/205 (52.2) 31/116 (26.7) 22/101 (21.8)
Aspirin,
n
(%) 39/135 (28.9) 68/203 (33.5) 67/115 (58.3) 60/102 (58.8)
No atrial fibrillation (
n
=
797)
Anticoagula-
tion,
n
(%)
19/444 ( 4.3) 234/786 (29.8) 66/499 (13.3) 22/326 ( 6.8)
Aspirin,
n
(%) 88/443 (19.9) 283/784 (36.1) 303/499 (60.7) 189/327 (57.8)
p
-value
1
0.0013
< 0.0001
0.0003
< 0.0001
p
-value
2
0.0266
0.4905
0.6269
0.8546
Atrial fibrillation
Valvular (
n
=
92)
Anticoagula-
tion,
n
(%)
12/63 (19.0) 48/91 (52.8)
20/34 (58.8) 15/45 (33.3)
Aspirin,
n
(%) 20/63 (31.8) 33/90 (36.7)
13/33 (39.4) 28/46 (60.9)
Non-valvular (
n
=
115)
Anticoagula-
tion,
n
(%)
4/71 ( 5.6)
58/112 (51.8) 10/81 (12.4)
7/56 (12.5)
Aspirin,
n
(%) 18/70 (25.7) 34/111 (30.6) 54/81 (66.7) 32/56 (57.1)
p
-value
1
0.0168
0.8915
< 0.0001
0.0117
p
-value
2
0.4420
0.3667
0.0073
0.7035
1
Chi-squared test for comparison of anticoagulation use.
2
Chi-squared test for comparison of aspirin use.
Table 4. Outcomes versus valvular disease status
in patients with atrial fibrillation
Variable
Valvular
atrial
fibrillation
(
n
=
92)
Non-valvular
atrial
fibrillation
(
n
=
115)
Effect
(95% CI
3
)
p
-value
Length of index
hospitalisation
1
11.2
9.6
1.63
(–0.56–3.83)
0.1438
Rehospitalisation
within 60 days
2
6.0
11.3
0.48
(0.15–1.52)
0.2046
Death within 180 days
2
24.8
13.2
2.11
(1.05–4.24)
0.0320
Death or rehospitalisa-
tion within 60 days
2
19.1
15.5
1.32
(0.66–2.65)
0.4268
1
LS means: difference presented for length of index hospitalisation.
2
Kaplan–Meier event rate.
3
Hazard
ratio
from Cox
regression model presented for rehospitalisation, death,
and death/rehospitalisation outcome.