Monday, 6 October 2008


So treatment perhaps avoids 31 events for every 1000 people who take it for 10 years

source: RPSGP and concise version (2004).

NHS policy directs the provision of a number of interventions (see Appendix C), including
lipid-lowering treatment, to all individuals that have had an event as well as all those at
30% or higher 10-year CHD event risks (with an aim to reduce this to 15% as resources

Despite the NHS thresholds, there is evidence from randomised, controlled trials that
individuals at 10-year risks as low as 5.6% can derive some benefit from lipid lowering

So whilst the NHS may decide not to fund treatment at this level due to the relative costineffectiveness
compared to other options and priorities, an individual, who has their own
beliefs and opinions, may decide that the benefits for them are worth the personal costs
involved (primarily financial to purchase the medicine, but also others including time and
risk of adverse effects). These people are potential users of OTC simvastatin and it is
being made available to allow a further approach to population risk reduction to be used by

Because at low levels of CHD risk the treatment itself may pose more of a risk than the
potential benefits it could bring there is a minimum threshold for use of a 10% 10-year risk.

Approximate 10 Year CHD Risk Action
Less than 10% Give lifestyle advice, recheck in the future
10% - 15% Give lifestyle advice and offer OTC simvastatin
More than 15% Give lifestyle advice and refer to their GP

This document uses the following terms to indicate approximate risk groups: .low. means
less than 10%, .moderate. means around 10-15% and .high. refers to those above this
level or those who are considered secondary prevention.

The first thing we must understand is that a cholesterol level alone is a relatively poor
predictor of CHD risk and the benefits of statins are not directly related to the initial level of
cholesterol anyway. This has important implications for deciding who to offer treatment to
and also how it is monitored (see later).

Formally estimating an individual.s 10-year CHD risk relies on the use of one of several
tools based on data from the Framingham studies, or similar (eg the Joint British Societies.
charts in the back of the BNF). Whilst the kind of risk assessment is ideal, it is more
complex and requires familiarity with the strengths and weaknesses of risk calculators, the
rules to apply when using them as well as recent blood pressure and cholesterol values.
Since OTC simvastatin is being targeted at a specific group of moderate risk people the
risk assessment process can be simplified somewhat. Despite this, over time Pharmacists
should use their CPD process to develop the skills needed to use formal risk calculators to
increase the strength of their assessments.

As part of the CHD risk assessment process it is good practice to measure the individual.s
blood pressure, or to ascertain a recent value, mainly for the purpose of ensuring those
who may have hypertension are referred to their GP. Where possible it is also good
practice to offer a cholesterol test, or to ascertain a recent value, again to refer those with
extremely high results to their GP but also to provide a baseline against which to measure

13. What are the Potential Benefits?
A common question from potential users of OTC simvastatin will be what are the benefits
of taking it and it is good practice to advise potential users of the likely effects.

We already have evidence from studies and experience of simvastatin 10mg that it lowers
cholesterol, probably by about 27% in practice. Whilst this probably indicates that it will
have a beneficial effect on lowering the risk of heart attacks and strokes, no specific
clinical trials of this type of treatment have been performed, so the extent of any benefit is
uncertain. Extrapolation based on the results of the three large primary prevention trials
suggests an approximate relative risk reduction of a quarter. Given this, an estimate of
benefit is shown below:

Taking 1000 people at 12.5% (mean of 10 - 15%) risk over 10 years:
! Over 10 years 125 will have a heart attack or fatal CHD
! The other 875 will not
! If all 1000 took treatment, the numbers having these events could fall to 94 (ie 25% of 125)
! The other 906 will not have one of these events
! So treatment perhaps avoids 31 events for every 1000 people who take it for 10 years

! In other words for every 32 people who take OTC simvastatin for 10 years one will
avoid a heart attack or fatal CHD that would have occurred had they not been on
! The other 31 will either not have an event anyway or still have an event despite
! There is no way of knowing in advance who will be in which group
Individuals must be advised that any benefit accrues over years: treatment is long-term
and must be continued to maintain any benefits.

No comments: