The SA Journal Diabetes & Vascular Disease Vol 12 No 1 (July 2015)

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28 VOLUME 12 NUMBER 1 • JULY 2015
RESEARCH ARTICLE SA JOURNAL OF DIABETES & VASCULAR DISEASE
calendar when patients filled their first prescription.40 There is likely
no single strategy that will work for all patients but studies show
that adherent patients have much better cardiovascular outcomes
than non-adherent patients, although some of the improvement
may also be ascribed to the correlation between adherence and
other healthy behaviours.41-44
According to a mathematical model of statin use in a population,
increasing statin adherence from 50 to 75% at five years would
prevent more events than lowering the risk threshold for prescribing
statins.45 Lastly, novel LDL-C-lowering therapies may be necessary
for patients with very high baseline LDL-C levels, such as is seen in
familial hypercholesterolaemia, and when patients are unable to
tolerate adequate doses of potent statins.46
In South Africa, the modal statin dose potency prescribed
to patients was 3, which was prescribed to 42.2% of the
individuals. Interestingly, although the very high-risk patients had
a disproportionately high share of the statin prescriptions with a
potency of 4 and 5, they also had a disproportionately high amount
of prescriptions with a potency of 2, and a disproportionately
low share of the prescriptions with a potency of 6. In addition,
although combination therapies may have the potential to benefit
some patients,37 we found that the use of combination treatment
with lipid-lowering therapies was rare in South Africa. Only seven
patients were co-prescribed statins and ezetimibe in this study.
DYSIS-South Africa had several limitations, including its cross-
sectional design, which did not permit follow up to assess the
effects of statins over time in either reducing CVD risk factors
or their ultimate effects in reducing CVD. In addition, the cross-
sectional nature of the study precludes us from drawing conclusions
of temporality based on observed associations. The study was
also only conducted in the private sector and does not therefore
provide any information on the care provided in the public sector,
which accounts for about 80% of patients in South Africa. As this
study was conducted in the private sector, the ethnic make-up of
the DYSIS study cohort is not representative of the South African
population at large.
Furthermore physicians were aware of the study purpose,
possibly making the results prone to a selection bias towards
patients with better-than-average lipid goal attainment. DYSIS by
its design is also unable to provide data on the important public
health question on what proportion of patients with an indication
for lipid-lowering therapy is actually being treated. Analysing
patients that return for follow-up consultation and are still taking
statins is not reflective of the entire statin treatment experience, as
patients discontinuing early and defaulting on follow up are not
captured. However, in spite of these potential limitations, the data
obtained during this cross-sectional, observational study of South
Africa has furthered our knowledge of CV risk and the factors that
contribute to persistent dyslipidaemia in statin-treated patients.
Conclusions
The DYSIS study for South Africa, like the DYSIS studies in other
countries and regions, indicates that large proportions of statin-
treated patients have persisting lipid abnormalities, which place
them at ongoing risk for CVD. While some observations with regard
to co-morbid conditions and demographics associated with lipid
goal attainment were expected, observations also demonstrate a
decreased likelihood of obtaining lipid goals among two ethnic
minority groups, independent of treatment, demographics and
other co-morbidities. These findings deserve further attention. As
statins remain among the most effective agents for preventing
CVD, the findings of this study emphasise the necessity for more
aggressive therapy in order to achieve recommended lipid targets,
so as to reduce the burden of cardiovascular disease, which is on
the increase not only in South Africa but worldwide.
Acknowledgements
The authors thank Dr Claus Jünger and Dr Steffen Schneider, Stiftung Institut für
Herzinfarktforschung, Ludwigshafen, Germany, for performing the statistical analyses,
Dr Myrga Zankel (MSD International) for general support of the study, and Dr Lori D
Bash (Merck & Co, Inc) for critical content review. We are indebted to all investigators
and patients in South Africa who participated in DYSIS. This study was funded by
Merck & Co, Ltd (New Jersey, USA).
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