Stephen J.LurieMD, PhD, Contributing EditorIndividualAuthor
To the Editor: We agree with the comments of
Dr Kumana and colleagues1 on the advantages
of using absolute risk reduction rather than RRR to evaluate treatment effectiveness,
but would like to emphasize that care is needed in interpreting the effectiveness
of statins using the absolute risk approach.
In primary prevention, the absolute risk reduction from treatment of
coronary heart disease (CHD) by statins is known to be largely determined
by the initial risk of CHD in the populations studied and the duration of
follow-up.2 The presence of other risk factors
such as smoking or hypertension imposes an additional risk, implying a greater
reduction in risk by statins in those with a risk factor than in those without.
The smaller expected NNTs in those exposed to risk factors compared with the
unexposed were consistently observed for all 4 risk factors in Table 2, thus
confirming the anticipated interaction between treatment of statins and the
major CHD risk factors.
Fontanarosa PB, Liu JLY, Tang J. Assessing Prevention Interventions by "Number Needed to Treat". JAMA. 2000;284(3):303-305. doi:10.1001/jama.284.3.303