In
their estimation of the life expectancy in the Whitehall cohort, Clarke et al
claimed that the decline in cardiovascular mortality that has occurred in the UK
population was partly attributable to changes in cholesterol concentrations.1
This statement can be questioned. Since a meta-analysis of the randomised and
controlled cholesterol lowering trials performed up to 1992 did not find any
effect on cardiovascular mortality,2 the alleged influence of
cholesterol lowering must have been caused by the statins introduced a few years
later. However, according to the mortality curves in their paper the decrease of
vascular mortality started already in the sixties, and the slopes are unchanged
from about 1980 up to today. The authors’ conclusion that more intensive cholesterol lowering can
result in further improvement in life expectancy is dubious as well.Recently
Sachdeva et al. reported that the mean LDL cholesterol in 136,905 patients
admitted because of an acute myocardial infarction was lower than normally.3
These authors also concluded that cholesterol lowering should be intensified, as
did Al-Mallah et al. who came up with similar results.4 However, at a
three-year follow-up, all cause mortality for those whose LDL cholesterol was
below 105 mg/dl at admission was almost twice as high as those whose LDL
cholesterol was higher.4 From the above we suggest
that the observed reduction of cardiovascular mortality is rather the result of
the increasing numbers of and quality of revascularization procedures than
cholesterol lowering.
Clarke
R, Emberson J, Fletcher A, Breeze E, Marmot M, Shipley MJ. Life expectancy
in relation to cardiovascular risk factors: 38 year follow-up of 19 000 men
in the Whitehall study. BMJ 2009;339:b3513. doi: 10.1136/bmj.b3513.
Ravnskov
U. Cholesterol lowering trials in coronary heart disease: frequency of
citation and outcome. BMJ 1992;305:15-9.
Sachdeva
A, Cannon CP, Deedwania PC, Labresh KA, Smith SC Jr, Dai D, et al. Lipid
levels in patients hospitalized with coronary artery disease: an analysis of
136,905 hospitalizations in Get With The Guidelines. Am Heart J
2009;157:111-7
Al-Mallah
MH, Hatahet H, Cavalcante JL, Khanal S. Low admission LDL-cholesterol is
associated with increased 3-year all-cause mortality in patients with non ST
segment elevation myocardial infarction. Cardiol J 2009;16:227-33.
Rapid Response:
Doubtful effect of cholesterol lowering
In
their estimation of the life expectancy in the Whitehall cohort, Clarke et al
claimed that the decline in cardiovascular mortality that has occurred in the UK
population was partly attributable to changes in cholesterol concentrations.1
This statement can be questioned. Since a meta-analysis of the randomised and
controlled cholesterol lowering trials performed up to 1992 did not find any
effect on cardiovascular mortality,2 the alleged influence of
cholesterol lowering must have been caused by the statins introduced a few years
later. However, according to the mortality curves in their paper the decrease of
vascular mortality started already in the sixties, and the slopes are unchanged
from about 1980 up to today.
The authors’ conclusion that more intensive cholesterol lowering can
result in further improvement in life expectancy is dubious as well.Recently
Sachdeva et al. reported that the mean LDL cholesterol in 136,905 patients
admitted because of an acute myocardial infarction was lower than normally.3
These authors also concluded that cholesterol lowering should be intensified, as
did Al-Mallah et al. who came up with similar results.4 However, at a
three-year follow-up, all cause mortality for those whose LDL cholesterol was
below 105 mg/dl at admission was almost twice as high as those whose LDL
cholesterol was higher.4
From the above we suggest
that the observed reduction of cardiovascular mortality is rather the result of
the increasing numbers of and quality of revascularization procedures than
cholesterol lowering.
Clarke
R, Emberson J, Fletcher A, Breeze E, Marmot M, Shipley MJ. Life expectancy
in relation to cardiovascular risk factors: 38 year follow-up of 19 000 men
in the Whitehall study. BMJ 2009;339:b3513. doi: 10.1136/bmj.b3513.
Ravnskov
U. Cholesterol lowering trials in coronary heart disease: frequency of
citation and outcome. BMJ 1992;305:15-9.
Sachdeva
A, Cannon CP, Deedwania PC, Labresh KA, Smith SC Jr, Dai D, et al. Lipid
levels in patients hospitalized with coronary artery disease: an analysis of
136,905 hospitalizations in Get With The Guidelines. Am Heart J
2009;157:111-7
Al-Mallah
MH, Hatahet H, Cavalcante JL, Khanal S. Low admission LDL-cholesterol is
associated with increased 3-year all-cause mortality in patients with non ST
segment elevation myocardial infarction. Cardiol J 2009;16:227-33.
Competing interests:
None declared
Competing interests: No competing interests