Around 65 per cent of patients in the US last year visited a doctor who had a payment or 'gift' from a drug company, and just 5 per cent of these were aware of the arrangement.
"These findings tell us that if you thought that your doctor was not receiving any money from industry, you're most likely mistaken," said researcher Genevieve Pham-Kanter from Drexel University.
The chances of a doctor receiving payments from the drugs industry were even higher among specialists. Around 85 per cent of orthopaedic surgeons and 77 per cent of gynaecologists and obstetricians regularly get payments from a drugs company.
The average payment was $193, although those in the Drexel survey were receiving an average of $510. Not enormous sums, perhaps, but enough to influence decision-making, the researchers say. "Drug companies have long known that even small gifts to physicians can be influential, and research validates the notion that they tend to induce feelings of reciprocity," said Pham-Kanter. "We may be lulled into thinking this isn't a big deal because the average payment amount across all doctors is low, but that obscures the fact that most people are seeing doctors who receive the largest payments."