The Need for NNT Labeling

One of the ironies of the consumer movement is that while Americans are increasing reading labels on food products and adjusting purchasing patterns accordingly, many continue to pay little attention to the medicines they take.  The very same people, who strive to eat only organic foods, willingly swallow pills — clearly not organic — on a daily basis without much thought as to the benefits derived or the risks involved.

This needs to change.  Both prescription and non-prescription drugs need to be clearly labeled with their NNT values.   A densely written disclaimer in small type, whether in a drug ad or in a drug package insert, is no substitute for NNT as a clear indicator of a drug’s effectiveness.  It should be as easy to find the NNT of a drug as to see the number of calories in a can of soda.

The benefits of NNT labeling are many.  In particular:

• Anyone who pays (or co-pays) for a drug or treatment should understand the degree to which there is an expected benefit.  At the very least, a high NNT value should provoke a thorough and frank discussion with their physician as to the expected benefits and risks.
• Every doctor needs to pay attention to the NNT of a drug being prescribed (or the tests and/or surgical procedure ordered). Knowing and explaining the NNT of a drug should help reduce pharmaceutical, legal, and/or patient pressures for over-diagnosis and treatment.
• Costs to the health system as a whole can be reduced directly by avoiding the expenses of ineffective drugs and procedures, and in directly by not incurring the expenses for the follow up and treatment of side effects.

One argument that has been advanced against NNT labeling is that the calculation of an NNT value is highly dependent on the individual risk characteristics of the underlying survey group.  Presumably, the NNT derived from a study of low risk individuals would be higher than the NTT derived from a high risk group.

While it may be difficult to derive a precise NNT number for a particular drug, the problem is not unlike standardization issues addressed for other label information.  Recommended Dietary Allowances ("RDAs") of vitamins, minerals, and nutrients, for example, are imprecise measures of the needs on any individual of a given age, weight, sex, etc.  Though any NNT measure may be inexact, what is most important is the relative order of magnitude of that number.  There is a significant difference between a drugs with an NNT of 1 (always effective), of 10 (often effective), of 100 (seldom effective), or 1,000 (virtually never effective).  With standard statistical tools, meaningful NNT measurements can be and should be prominently publicized on drug labels.