WASHINGTON - THE customary annual physical check-up at the doctor's office may not be worth the time or money, researchers said on Monday.

About 63 million US adults visit a doctor annually for a routine medical or gynecological check-up at a total cost of US$7.8 billion (S$11.7 billion), according to a study intended to help answer questions about the value of this trip to the doctor's office.

More than 80 per cent of preventive care provided by doctors does not take place during this annual check-up, the study showed. And more than US$350 million worth of potentially unnecessary medical tests are performed, the researchers said.

'We need to question encouraging everybody to come in for an annual physical,' Dr Ateev Mehrotra of the University of Pittsburgh School of Medicine and the RAND, who led the study, said in a telephone interview.

'There's a lot of money, a lot of visits, a lot of adults going to see their doctor for annual physical exams with a real unclear benefit. It's the No. 1 reason adults see their doctor, and yet we don't know whether it's helpful or not,' he added.

Dr Mehrotra said no major North American clinical organisation advises people to get an annual medical check-up, but most adults think they should get one and most doctors recommend them.

'I'm not saying that preventive care itself is not helpful. It is clearly helpful - mammograms, pap smears, cholesterol screening, colon cancer screening, prostate cancer screening.'

'And patients should get those. But does it need to happen at this special visit? Or can we get it some other way?' he said.

The study appears in the Archives of Internal Medicine. -- REUTERS