The inverse benefit law: how drug marketing undermines patient safety and public health

Abstract

Recent highly publicized withdrawals of drugs from the market because of safety concerns raise the question of whether these events are random failures or part of a recurring pattern. The inverse benefit law, inspired by Hart's inverse care law, states that the ratio of benefits to harms among patients taking new drugs tends to vary inversely with how extensively the drugs are marketed. The law is manifested through 6 basic marketing strategies: reducing thresholds for diagnosing disease, relying on surrogate endpoints, exaggerating safety claims, exaggerating efficacy claims, creating new diseases, and encouraging unapproved uses. The inverse benefit law highlights the need for comparative effectiveness research and other reforms to improve evidence-based prescribing.

FIGURE 1

Distribution of disease or risk factors within a population. Note. X indicates an evidence-based threshold for beginning drug therapy (portion of population eligible to receive a drug indicated by area under the curve to the right of X). Y indicates an industry-marketing-based threshold for beginning drug therapy (portion of population eligible to receive a drug indicated by area under the curve to the right of Y). The “left shift” from X to Y reduces overall drug efficacy by administering the drug to patients at lower risk or with less severe symptoms, thereby raising the number needed to treat, and exposes many more people to the risk of adverse drug reactions.