Antibiotic overuse causes great social harm yet is largely absent from public discussion of drug policy. There is a textbook external effect of an antibiotic prescription: the more antibiotics are used, the higher the risk we all face of resistant infections. As a result, there tends to be too much use of antibiotics. There have been ongoing efforts to reduce use of antibiotics, particularly in the context of treating respiratory infections, in part by educating GPs, the supply side of the relationship, on appropriate use.
In “Patient knowledge and antibiotic abuse: Evidence from an audit study in China” Janet Currie, Wanchuan Lin, and Wei Zhang consider the demand side of the relationship: what is the effect of patient knowledge on antibiotic use? The authors use a field experiment conducted in China, where antibiotic abuse is particularly severe possibly because physicians have substantial financial incentives to write expensive prescriptions.
We sent pairs of well-matched simulated patients, A and B, to the same physician, with a short time interval between their audits. The pair followed the same transcript except that following the physical examination, patient A said “I learned from the internet that simple flu/cold patients should not take antibiotics.” Thus, A signaled to the physician that they had some knowledge of inappropriate antibiotic use, while B did not.
We find that the signal reduced the probability of receiving an antibiotic prescription by 25 percentage points, from 64% for patient B to 39% for patient A. The signal also reduced drug expenditures from an average of 145.81 RMB for patient B to 105.84 RMB for patient A. Finally, patients who signaled knowledge of antibiotics received more information about possible drug side effects than apparently uninformed patients, but fewer polite responses from physicians.
Estimating the extent of demand inducement is notoriously difficult, and this experimental evidence is striking. I wonder if informed patients would still encounter rude responses from physicians if the physician’s compensation were held constant?