Modelling the decline in coronary heart disease deaths in England and Wales, 1981-2000: comparing contributions from primary prevention and secondary prevention
Readers of this article might be bamboozled into thinking that
pharmacological intervention to reduce cholesterol levels is ineffective
at a population level. Digging into the assumptions of the IMPACT model
shows that the low apparent impact of statins for primary prevention
occurs because the model assumes a 3% uptake of statin treatment for
primary prevention in the population for which such treatment is
indicated. This figure is derived from a single study conducted in
Nottingham general practices between 1996 and 1998. The study in question
did not even differentiate statins prescribed for primary or secondary
prevention. This study also showed rapidly changing statin usage (a four-
fold increase in statin precribing within 2 years). Interpretation and
extrapolation of this data to the whole of the UK in 2000 (or even 2003,
as suggested in the discussion) must be tenuous at best. I suggest the
authors may wish to question the realism of some of their own assumptions.
Even using the authors' own (unspecified) assumptions regarding the
numbers eligible for such treatment, increasing the uptake of statins for
primary prevention to, say, 80% would increase the estimate of annual
deaths prevented or postponed by statins used for primary prevention to
145*80/3=3867. This would provide a proven evidence-based intervention,
in contrast to the exhortation given by the authors to focus on attempts
to encourage healthier diets.
Making different assumptions about statin prescribing would also
quickly erode the number of prevented or postponed deaths the authors
attribute to dietary changes, since these are calculated as the residual
of prevented deaths after those attributable to statins have been
estimated. For example, if statin uptake for primary prevention were 30%,
the estimated deaths prevented by statins used for primary prevention
would be 1450 per annum and by dietary change 4710-1450=3260, rather than
the 145 and 4565 suggested in the paper.
Competing interests:
I have received research funding, educational and travel grants from pharmaceutical manufacturers of lipid-lowering drugs
Rapid Response:
Realistic assumptions...
Readers of this article might be bamboozled into thinking that
pharmacological intervention to reduce cholesterol levels is ineffective
at a population level. Digging into the assumptions of the IMPACT model
shows that the low apparent impact of statins for primary prevention
occurs because the model assumes a 3% uptake of statin treatment for
primary prevention in the population for which such treatment is
indicated. This figure is derived from a single study conducted in
Nottingham general practices between 1996 and 1998. The study in question
did not even differentiate statins prescribed for primary or secondary
prevention. This study also showed rapidly changing statin usage (a four-
fold increase in statin precribing within 2 years). Interpretation and
extrapolation of this data to the whole of the UK in 2000 (or even 2003,
as suggested in the discussion) must be tenuous at best. I suggest the
authors may wish to question the realism of some of their own assumptions.
Even using the authors' own (unspecified) assumptions regarding the
numbers eligible for such treatment, increasing the uptake of statins for
primary prevention to, say, 80% would increase the estimate of annual
deaths prevented or postponed by statins used for primary prevention to
145*80/3=3867. This would provide a proven evidence-based intervention,
in contrast to the exhortation given by the authors to focus on attempts
to encourage healthier diets.
Making different assumptions about statin prescribing would also
quickly erode the number of prevented or postponed deaths the authors
attribute to dietary changes, since these are calculated as the residual
of prevented deaths after those attributable to statins have been
estimated. For example, if statin uptake for primary prevention were 30%,
the estimated deaths prevented by statins used for primary prevention
would be 1450 per annum and by dietary change 4710-1450=3260, rather than
the 145 and 4565 suggested in the paper.
Competing interests:
I have received research funding, educational and travel grants from pharmaceutical manufacturers of lipid-lowering drugs
Competing interests: No competing interests