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CARDIOVASCULAR JOURNAL OF AFRICA • Vol 26, No 5, October/November 2015
AFRICA
37
1
PATH, Seattle, USA
2
Institute for Health Metrics and Evaluation, University of
Washington, Seattle, USA
Background and objectives:
Tobacco taxation remains an effec-
tive but under-utilised means of reducing the burden of smok-
ing-related diseases globally. Estimates of price elasticity of
demand (PED), i.e. the ‘sensitivity’ of cigarette use to changes
in prices and taxes vary widely across countries and studies, and
recent reports suggest that variations in the intensity of cigarette
consumption influence price sensitivity. We sought to explore
cross-country variations in PED accounting for variations in the
relationship between smoking intensity, price and income level.
Methods:
We obtained Global Burden of Disease 2013 estimates
of per capita cigarette consumption in 181 countries over five
years (2008–2012). We calculated the average price per pack
of cigarettes in each country-year using tobacco sales data.
We included, as controls, per capita gross domestic product
(GDPpc) as a proxy for income as well as indicator variables
for the presence of other tobacco policies. We used quantile
regression to model PED across varying levels of cigarette
consumption, and we assessed statistical significance using
robust standard errors.
Results:
We estimated average PED for cigarettes to be –0.15
during 2008–2012, although it was smaller in lower-consumption
settings (e.g. –0.11 at the 25th percentile of consumption) and in
higher-consumption settings (e.g. –0.12 at the 75th percentile of
consumption) compared to moderate-consumption settings (e.g.
–0.22 at the median of consumption). We found that PED also
varies depending on a country’s level of economic development.
Low-income countries were expected to be less price sensitive,
while high-income countries were expected to be more price
sensitive. Our results were robust to several alternative model
specifications.
Conclusions:
Globally, there is significant heterogeneity in PED
for cigarettes. Countries where the intensity of smoking is very
high or low are less price sensitive than moderate-consumption
countries. Furthermore, wealthier countries are more price
sensitive than poorer countries. Our findings raise concerns
about the relative effectiveness and potentially regressive nature
of raising cigarette prices in lower-income, lower-consumption
settings (e.g. in sub-Saharan Africa) in the absence of robust
non-tax tobacco policies.
CONTEMPORARY ESTIMATES OF MORBIDITY AND
MORTALITY RATES OF RHEUMATIC HEART DISEASE
IN SOUTH AFRICA: OUTCOMES FROM THE CAPE
TOWN COMPONENT OF THE GLOBAL RHEUMATIC
HEART DISEASE REGISTRY
Zühlke Liesl*, Engel ME, Mayosi BM
Department of Medicine, Groote Schuur Hospital, Cape Town,
South Africa;
zuhlke@telkomsa.netIntroduction:
The Global Rheumatic Heart Disease Registry
(the REMEDY study) is a prospective study of the baseline
characteristics, complications and incidence of sequelae in
RHD, and included 531 adults and children from Cape Town.
Methods:
This report describes the characteristics and morbid-
ity estimates at enrolment of patients from two South African
sites. We also determined the incidence of adverse cardiovas-
cular events: congestive cardiac failure (CCF), stroke, infective
endocarditis, major bleeding, peripheral embolism, rheumatic
fever recurrence, hospitalisation, surgery or intervention, preg-
nancy and all-cause mortality over a 24-month period.
Results:
The RHD patients enrolled at two Cape Town tertiary
institutions were young, predominantly female, and largely
post-surgical but with a high prevalence of complications at
enrolment. Over the follow-up period, we documented an event
rate of 203.56 per 1 000 person-years and an annual mortal-
ity rate of 4.1% in the Cape Town cohort. The most frequent
event in the 24-month period was hospitalisation (13.2%/year)
followed by surgery (4.24%/year), CCF (3.86%/year), major
bleeding and stroke (1.41/year). Enrolment in cardiac failure
(hazard ratio 15.73, 95% CI: 3.94–62.7,
p
<
0.0001) and develop-
ment of a subsequent episode of CCF conferred the highest risk
of mortality (hazard ratio 11.1, 95% CI: 5.6–21.96,
p
=
0.047).
Conclusion:
RHD patients in Cape Town had a mortality rate
of 4.1%, which was comparable with the general population.
There was a heavy burden of morbid and mortal events with an
incidence of 203.56 events per 1 000 person-years. These find-
ings point to the need for targeted interventions to identify and
manage at-risk individuals.
INCIDENCE, PREVALENCE AND OUTCOME OF RHEU-
MATICHEARTDISEASE IN SOUTHAFRICA: A SYSTEM-
ATIC REVIEW OF CONTEMPORARY STUDIES
Zühlke Liesl*, Engel ME, Watkins D, Mayosi BM
Department of Medicine, Groote Schuur Hospital, Cape Town,
South Africa;
zuhlke@telkomsa.netBackground:
Twenty years after its first democratic election,
South Africa is experiencing a health transition. The impact of
change on the incidence, prevalence and outcome of rheumatic
heart disease (RHD) is unknown.
Methods:
We conducted a systematic overview of the incidence,
prevalence and outcomes of RHD in South Africa over the past
two decades according to a published protocol.
Results:
The overall crude incidence of symptomatic RHD was
24.7 per 100 000 (95% CI: 22.1–27.4) population per annum
among adults (
>
13 years) in Soweto, while the prevalence of
asymptomatic echocardiographic RHD in schoolchildren was
20.2 cases per 1 000 children (95% CI: 15.3–26.2) in Cape Town.
The 60-day mortality after admission with acute heart failure
due to RHD was 24.8% (95% CI: 13.6–42.5%) and 180-day
mortality was 35.4% (95% CI: 21.6–54.4%). Post-operative
mortality at 30 days was 2% (95% CI: 0.0–4%). Post-surgical
survival was over 75% at five years, and over 70% at 10 years.
Cause-specific mortality rate per 100 000 population decreased
from 1.27 (95% CI: 1.17–1.39) in 1997 to 0.7 (95% CI: 0.63–
0.78) in 2012.