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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 28, No 2, March/April 2017
AFRICA
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of 231 592 in Gaborone, plus patients referred from other areas
of the country.
10
The study was granted ethical clearance by the
University of Botswana and PMH institutional review boards,
and permission to carry out the study was obtained from the
Ministry of Health. Written informed consent was obtained
before data collection from all participants, or their relatives, in
cases where the patient was unable to consent.
Consecutive AHF patients aged 18 years of age or older
admitted to the hospital between February 2014 and February
2015 were enrolled in the study. HF was defined according to the
criteria of the European Society of Cardiology (ESC), and both
decompensated HF in patients with a previous HF diagnosis
and new-onset AHF were included.
11
Patients were excluded if
they had other diseases with a short-term prognosis, such as
malignancy or World Health Organisation stage 4 HIV infection.
From the enrolled patients, symptoms and signs of HF were
ascertained, and the admission functional status was assessed
using the New York Heart Association (NYHA) classification.
12
Any pre-hospital medical history of atrial fibrillation, valvular
heart disease, diabetes mellitus, hypertension, HIV infection and
cerebrovascular disease was also recorded.
On the day of enrolment, three blood pressure measurements
were obtained and averaged.
13
The blood pressure measurement
made on admission was also recorded. A patient was considered
hypertensive on the basis of a self-reportedhistoryof hypertension
and/or the use of blood pressure-lowering medications or a
sustained blood pressure
≥
140/90 mmHg during the course of
the admission.
14
Complete blood counts, serum electrolytes, urea, creatinine,
uric acid and N-terminal pro-brain natriuretic peptide
(NT-proBNP) analyses were performed on all enrolled patients.
Moderate to severe renal failure was diagnosed by an estimated
glomerular filtration rate (eGFR) of less than 60 ml/min/1.73 m
2
at admission and/or by patients being on dialysis.
1
Patients whose
haemoglobin values were less than 10 g/dl were classified as
having anaemia.
7,1
Testing for HIV was done for patients whose
sero-status was unknown.
Echocardiography using a Vivid S™ S6 machine (GE
Healthcare view, USA) was performed on all patients by two
cardiologists (JM and MG) according to the American Society
of Echocardiography guidelines.
16
Two-dimensional M-mode
measurements of left ventricular (LV) internal dimension,
interventricular septal thickness and posterior wall thickness were
made at end-diastole and end-systole.
16,17
M-mode measurements
for the left atrial diameters were obtained at end-systole.
Left ventricular ejection fraction (LVEF) was calculated from
left ventricular volumes obtained at end-diastole and end-systole
using the modified biplane Simpson’s rule in the apical four- and
two-chamber views.
16
LVEF
<
45% was used to define significant
LV systolic dysfunction, whereas patients with LVEF
>
45% were
assessed as having HF with preserved ejection fraction. Right
ventricular dysfunction was assessed by a tricuspid annular plane
systolic excursion (TAPSE)
<
16 cm.
17
Available clinical and echocardiographic data were used to
assign a likely primary aetiology to each patient based on the ESC
guidelines and the Heart of Soweto study definitions.
11,18
Ischaemic
HF was determined by the presence of LV systolic dysfunction,
regional wall-motion abnormality, electrocardiographic
abnormalities, and angiographically confirmed diagnosis of
coronary artery disease.
18
Patients with LV systolic dysfunction
and dilated left ventricle (LVEDD
>
55 mm) of indeterminate
cause were classified as having idiopathic dilated cardiomyopathy.
18
Peripartum cardiomyopathy was diagnosed in patients with
echocardiographic features of dilated cardiomyopathy without
a demonstrable cause, and if disease presented for the first
time within the last trimester of pregnancy or in the first five
months postpartum.
19
Other causes of HF included pericardial
disease, congenital heart disease, amyloidosis, hypertrophic
cardiomyopathy, restrictive cardiomyopathy, thyroid heart
disease and HIV infection.
20
Hospital length of stay (LOS) and in-hospital mortality were
assessed for each participant. LOS was defined as the number
of days from hospital admission to discharge. After discharge,
patients were followed up at the PMH out-patient cardiac clinic
for clinical evaluation and medication adjustment or titration.
HF medications at discharge or at end-of-study follow up
were documented, and patients were contacted whenever they
missed their scheduled out-patient appointments, to reschedule
for another appointment. In the event that participants were not
contactable, the next of kin/nominated contacts were contacted.
For participants who relocated to other health facilities, their
information was retrieved from the nationwide electronic
medical records (EMR) database, which contains clinical notes,
laboratory results, pharmacy data and information on dates of
patient clinic and hospital visits.
Information on mortality was collected at 30, 90 and 180 days
by telephone contact with their next of kin/nominated contacts
and/or from the EMR. Participants who could not be contacted
or traced through the EMR after discharge were declared as lost
to follow up. Other patients were censored at the last available
contact or clinic visit.
Statistical analysis
All data were analysed using SPSS version 23.0 for Windows
(SPSS Inc, Chicago, IL, USA), and summary statistics were
calculated for all patient variables. Continuous variables are
presented as means
±
one standard deviation (SD) or medians.
For non-continuous variables, absolute and relative frequencies
(%) were used. Comparisons between normally distributed
continuous variables were performed using the Student’s
t
-test or
Kruskal–Wallis test. Associations between categorical variables
were tested with contingency tables and Pearson’s chi-squared test;
p
-values less than 0.05 were considered statistically significant.
Results
From the 202 patients admitted with HF during the study
period, 193 (95.5%) were enrolled. Nine patients were excluded
from the study because they failed to meet the inclusion criteria,
four were unwilling to participate, two died and one was
transferred to another hospital before enrolment. More than
half of the enrolled patients (56%) were referrals from health
facilities outside Gaborone.
Table 1 shows the clinical and demographic characteristics
of the study population. Most patients were black Africans
(98.4%). Cigarette and alcohol use was found in 13 and 15%,
respectively. The mean age of the patients [
±
standard deviation
(SD)] was 54.2
±
17.1 years, ranging from 20 to 89 years.
Smoking was significantly more common in the men (18.3%)