Correspondence

With the completion of the Human Genome Project, interest in the provision of patient-centred approaches for clinical diagnosis and treatment of disease that allow for individual variability, known as precision medicine or personalised medicine, has increased. On the basis of the belief that only genetics can be used to definitively explain common features of our physiology and pathophysiology, our genome might be able to accurately indicate the individual risk of developing a life threatening impairment during our lifetimes. However, human responses to even the most extreme environmental challenges are not all the same, as exemplified by the differing adaptations to high altitude, in which low oxygen is the main stimulus for adaption but physiological and genetic adaptations differ ie, between ethnic groups (Tibetans, Ethiopians, and Andeans) with lifelong multigenerational exposure to high altitude.1 Similarly, whether genomic science will soon provide in-depth understanding of common hereditary factors in, for example, heart disease, cancer, diabetes, mental illness, and neurodegeneration is also unknown.2 The previously mentioned idea, known as “common-disease common-variant” hypothesis, for most major medical conditions has in fact been rejected by the Human Genome Project. An ideal genetic test for clinical purposes would have 100% sensitivity and specificity an d identify a genetic disorder that is highly penetrable. Additionally, the test would need to be clinically actionable and provide information that could not otherwise be obtained in normal clinical practice. Unfortunately, few genetic markers have these characteristics. Usually, the presence of a particular genetic www.thelancet.com Vol 385 April 25, 2015

polymorphism or haploid pattern is associated with only a slight increase in the risk of development of a certain disease or a differential response to a therapeutic drug. Gene scores for several risk variants are also typically not clinically informative. These scores are not useful for complex cardiovascular disorders and diabetes in which large gene-environment interactions are known to exist and in behavioural interventions that have proven to be highly effective at lowering of patient risk of disease and in secondary prevention. 3 As shown in human migration studies and changing disease patterns over time (eg, obesity and diabetes), our physical activity and dietary habits, versus only genetic factors, have the biggest effect on disease risk. Novel ideas also suggest soft inheritance with mechanisms such as maternal-fetal programming that makes human phenotypes more complicated than simply being based on coding regions of DNA.4 Another challenge of precision medicine, in the case of cancer, is that targeted drug therapy based on the analysis of tumour mutations might only kill susceptible clones, which would leave resistant and adaptive cells to cause a drug-resistant recurrence. Implementation of precision medicine would need each person’s genetic profile to be obtained, raising complex ethical, legal, financial, and social issues. On the basis of these well founded concerns and key biological and behavioural barriers, careful and critical debate about the role of the precision medicine framework in the future of medicine is needed. Treatment schemes that are difficult to validate could become increasingly driven by the politically favoured funding of genetic and molecular research with so-called big science initiatives because of the mistaken belief that this research will create a healthy society.5 Although precision medicine will almost certainly

be used in niche applications, if widely implemented, it could be a distraction from low cost and effective population-wide interventions and policies. We believe precision medicine is not the route to a healthy world and instead urge a renewed and increased focus on public health and prevention.

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Is precision medicine the route to a healthy world?

We declare no competing interests. The views expressed are those of the authors and not necessarily those of their institutions.

*John H Coote, Michael J Joyner [email protected] School of Clinical and Experimental Medicine, University of Birmingham, Birmingham, UK (JHC); and Mayo Clinic, Rochester, MN, USA (MJJ) 1

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Beall CM. Andean, Tibetan, and Ethiopian patterns of adaptation to high-altitude hypoxia. Int Comp Biol 2006; 46: 18–24. Noble D, Jablonka E, Joyner MJ, Muller GB, Omholt SW. Evolution evolves: physiology returns to centre stage. J Physiol 2014; 592: 2237–44. Joyner MJ, Prendergast FG. Chasing Mendel: five questions for personalized medicine. J Physiol 2014; 592: 2381–88. Archer E. The mother of all problems. New Sci 2015; 225: 32–33. Collins FS, Varmus H. A new initiative on precision medicine. N Engl J Med 2015; 372: 793–95.

β blockers in patients with heart failure and atrial fibrillation The results from the study by Dipak Kotecha and colleagues1 are surprising. In view of the differences between patients with heart failure and sinus rhythm and patients with atrial fibrillation, Kotecha and colleagues’ warning against the use of β blockers needs to be viewed in context and several important points have been overlooked. First, the renal function (estimated glomerular filtration rate 64 mL/min vs 61 mL/min) of patients with sinus rhythm and basal functional status was improved compared with patients with atrial fibrillation. Although the difference

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Is precision medicine the route to a healthy world?

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