New paper quantifies harms and benefits of common preventive activities

Evelyn Lewin

3/12/2018 1:13:59 PM

While all health strategies recommended by the RACGP’s Red Book are beneficial, a new paper quantifies the benefits and harms of various preventive activities.

GPs’ limited opportunity to discuss preventive health strategies means quantifying their risks, benefits and reduction in mortality can help guide towards which strategies to recommend.
GPs’ limited opportunity to discuss preventive health strategies means quantifying their risks, benefits and reduction in mortality can help guide towards which strategies to recommend.

According to the RACGP’s Guidelines for preventive activities in general practice (the Red Book), approximately 32% of Australia’s total burden of disease can be attributed to modifiable risk factors.
Yet, preventive intervention is the primary reason for only seven in every 100 clinical encounters, so such activities are often initiated opportunistically by GPs.
There are ample choices of recommendations on offer, with the Red Book collating 32 preventive activities for adults and 24 for children. But as all of those recommended activities are beneficial, it can be challenging to know on which strategies to focus.
Now a new paper in the latest issue of the Australian Journal of General Practice (AJGP), ‘Quantifying the benefits and harms of various preventive health activities’, addresses that issue.
Co-author Professor Chris Del Mar, an evidence-based medicine (EBM) specialist, told newsGP the idea for the paper arose over a long period of time, stemming from concern regarding the increasing number of preventive activities accumulating in the Red Book.
‘[We were] wondering how, as GPs, [we] can ever decide which preventive activity we should do first ... because we can’t do everything,’ he said.
Professor Del Mar said he suspects GPs quite often ‘choose the thing we think is most medical, like a Pap smear test, or the thing that’s easiest to reach for, like a sphygmomanometer’.
‘But it occurred to us, one helpful thing would be to have a ranking of the benefits and the harms of each preventive activity so we can have them at least ranked in the right order so we can choose,’ he said.’
The paper looks at the potential downfalls of a sample of common preventive health recommendations, such as overdiagnosis and potential overtreatment, and weighs that up against potential benefits, along with the reduction in expected deaths.
‘We thought we would try and get a sample, just a few done, to see how it might work,’ Professor Del Mar explained.
Where possible, information came from meta-analyses of randomised controlled trials. When that was not possible (such as for smoking cessation), the authors quantified the evidence for benefit from observational cohort studies.
The authors restricted the analysis to a single age group, 50 years of age, to simplify the estimates.
They found that smoking cessation led to 24.2 fewer deaths in males and 15.4 fewer deaths of females per 1000 people per decade, while weight loss – going from a body mass index (BMI) of 35 down to 30 – led to 19.7 fewer deaths in males and 11.8 in females.
Meanwhile, lipid lowering with a statin in metabolic syndrome led to 2.1 fewer deaths in males and 0.7 fewer deaths in females per 1000 people per decade.
Being invited for regular mammography yielded 0.5 fewer breast cancer deaths, while participating in faecal occult blood testing (FOBT) biennially led to 0.5 fewer deaths in males and 0.3 in females.
As an epidemiologist, these results did not surprise Professor Del Mar.
‘But I think it might surprise some GPs who are not so well acquainted with managing population data,’ he said. ‘And I think that that’s where the value of doing this might really be something useful.’
Professor Del Mar hopes this area is investigated further and that these results influence how GPs choose which preventive activity to discuss with their patients. He also believes the paper would be ‘a useful addition to the Red Book itself’ and hopes it may lead to the development of decision aides for patients.
‘We should have these things available for all the preventive activities that we recommend in the Red Book so that we can help people make decisions which incorporate their own preferences [and] what patients are worried about,’ he said.
‘So we can put all that information into the melting pot and help patients make a choice that’s right for them.’

AJGP preventive health red book

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