Precision medicine: improving accuracy, reducing error

In 1892 William Osler wrote “It is more important to know what kind of a patient the disease has, than to know what kind of a disease the patient has.” Although health-care practices have traditionally followed a one-size-fits-all method, precision medicine aims for a more tailored approach. However, despite much hype on the potential of precision medicine, until now there has been little consensus on its exact definition and clinical relevance. More data does not necessarily mean improved decision making and whether precision medicine can be used for multifactorial conditions, such as obesity and diabetes, is still a matter of debate. The Lancet Diabetes & Endocrinology has just published a four-paper Series on the current status of precision medicine in cardiometabolic health. The Series aims to standardise terms and concepts, propose new models for disease classification, and discuss future directions including implementation and feasibility of precision medicine approaches in low-income and middle-income countries (LMICs). Coinciding with publication of the Series was the second international consensus report from the Precision Medicine in Diabetes Initiative, which discusses precision medicine in diabetes and outlines key targets for its clinical implementation. The first paper of The Lancet Diabetes & Endocrinology Series proposes a novel translational framework that aims to help the process of translating precision medicine into clinically meaningful decisions. There is still confusion over what precision medicine entails. Often, genomic research is seen as the predominant, if not only, component, which can lead to the assumption that precision medicine solely involves costly techniques and technologies that are not yet widely available. However, precision medicine can incorporate genetic, environmental, and clinical markers to improve accuracy at every stage of medical management—prevention, diagnosis, prediction, treatment, monitoring, and prognosis. To avoid exacerbating current health-provision disparities, there must be a concerted effort to ensure that people from all backgrounds and all nations are included in each aspect of precision health care. The second paper of our Series discusses the challenges and implications of adopting precision medicine in LMICs. Establishing large reliable databases is key, but despite a large proportion of people with diabetes residing in LMICs, most of the current research is performed in cohorts of mainly European ancestry. Promisingly, there have been positive steps forward, with projects such as GenomeIndia which aims to perform whole genome sequencing, increasing opportunities for precision medicine. However, implementation requires more than data. There will need to be a shift in health-care policy and public health to ensure that the public, stakeholders, and politicians are aware of precision medicine and how it can be utilised to combat conditions like diabetes. Furthermore, practical measures such as ensuring there are enough health-care workers skilled in precision health care and a suitable IT infrastructure that can process high-volume data need to be considered and planned for. Current diagnosis and management methods of diabetes and obesity do not reflect the complex and multifaceted nature of these conditions. Globally, diabetes is diagnosed through measurement of a single parameter—glucose. Likewise, overweight and obesity are classified according to BMI, irrespective of differences in body composition, ethnic background, gender, or lifestyle. The third paper of the Series proposes a model for diabetes classification that incorporates the interactions of different underlying causational processes, such as obesity and insulin resistance. Similarly, there is also much interest in devising obesity subtypes that reflect the different genetic, lifestyle, and environmental exposures of individuals, and can help clinicians with the management and treatment of the condition. The final paper in the Series discusses obesity heterogeneity and proposes an obesity-centred multi-disease management plan that targets both obesity and its comorbidities, especially diabetes. An overarching theme in the Series is the emphasis on greater collaboration and accord between governments, policy makers, and scientists, from both high-income countries and LMICs, on what the future of precision medicine should be in practical terms. Often described as the next evolution of contemporary medicine, there is great opportunity to focus on the person and not the disease. However, it is important that in these endeavours, traditional public health and population-level campaigns that have shown effectiveness in reducing and managing conditions such as obesity are not deprioritised.