Like everyone else, public health insurances only have a limited amount of money, and therefore constantly need to make decisions which treatments to fund, and which are too expensive. That way, some treatments, although they have a health benefit, do not get funded, because they cost too much, and the money instead goes to treatments with a higher utility.
This applies to drugs, but also to diagnostic tests. From the point of view of insurers, genome sequencing is just another such test. The question then is, is it the best way to spend health insurance money?
In a recent publication in the journal Science Translational Medicine, Nicholas Roberts and coworkers partially address this question. They estimate the potential of whole genome sequencing to provide clinically useful information on the disease risk of people who are currently healthy.
Their result: Even in the best of circumstances, for most people sequencing will be uninformative about their risk for the majority of common diseases.
However, they also find that there is also a good chance that sequencing will provide useful information about at least one disease. This means that if you are particularly concerned about getting a specific disease, sequencing will probably not tell you anything new. On the other hand, it might well warn you about your risk of developing a disease you never even thought of before. But even then, the predictive value is likely to be quite limited.
This is interesting, but as the authors acknowledge, it comes with some caveats. Firstly, it covers only common diseases. For diseases that are caused by single genes, sequencing is much more likely to give useful results. Also, it assumes that people are sequenced after their birth, whilst some of the value of sequencing lies with prenatal diagnosis. It also ignores the possibility of sequencing only those people who are most likely to benefit, such as those that already show certain symptoms.
In summary, Nicholas Roberts and his colleagues pour cold water on the idea that sequencing everyone is going to have a large impact on how disease risks for common diseases are assessed for asymptomatic patients. On the more important question of whether sequencing everyone will be worth the cost in clinical practice, the jury is still out.
In next week's post, I will attempt to answer the related question of what the utility of sequencing needs to be in order to offset its cost.