The BMJ's summary of the new NICE guideline on lipid modification omits the key information that clinicians will need to help inform patients' own treatment choices: the NNT for statin treatment in different risk groups, at different levels of treatment intensity. This is not a shortcoming of the BMJ piece. Although NICE say that doctors should share this information with their patients, there is no such summary in the NICE guideline itself.
The most attentive reader might find – in row 10 of 32, in table 43, on page 143 – that for every thousand people without cardiovascular disease taking a statin, overall there would be 7 fewer non-fatal myocardial infarctions. To establish the time period over which this figure applies, or whether it relates to the important new 10% 10-year risk population, would require downloading and reading Appendix C, a separate document. Table 60 summarises data from a 2013 Cochrane review, which (arguably) relates to a 15% 10-year risk population, and reports an NNT of 88 for “total CHD events” over 5 years. An attentive reader could further deduce that these events are non-fatal, since the NNT for all-cause mortality in the same table is higher.
NICE advises doctors to inform their patients about the benefits they can expect from statins. The implication is that after reading a 302 page NICE report, and finding - after many hours of close scrutiny - the numbers in the paragraph above, busy GPs should then go and do their own additional literature search, read and critically appraise the trial data, synthesise the information - at different risk strata and treatment intensities - and then use the appropriate formulae to convert the information they have synthesised into NNT for easy interpretation by patients. This is the kind of work most clinicians might hope that NICE - a well-resourced national body with extensive technical expertise – would have done for them.
Clear summaries of information on benefit and risk are the bedrock of informed patient choice. They should be our highest priority and not a poor second cousin. A simple table in NICE's own summaries - giving NNTs we know, and noting those we don't - might be a good place to start. I hope that others will have suggestions of their own.
 Goldacre Ben, Smeeth Liam. Mass treatment with statins BMJ 2014; 349:g4745
Competing interests: I receive income from writing and speaking to lay and professional audiences on problems in science, including poor communication of risk, and badly designed trials.