LONDON Doctors are overprescribing antibiotics for common sinus infections and related conditions, possibly in the false belief they may help in cases where symptoms are protracted, researchers reported on Friday.
Bacteria can cause rhinosinusitis -- an inflammation of the sinuses -- but a virus such as the common cold is often a more likely culprit so antibiotics seldom work, the researchers reported in the journal Lancet.
Yet doctors still dole out the drugs more than they should. In the United States, for instance, 80 percent of sinus patients are prescribed an antibiotic while the proportion ranges from 72 percent to 92 percent in Europe.
"What tends to happen in practice is when patients have had symptoms for a while and go see their family doctor, the doctor assumes they have a bacterial infection and gives them antibiotics," said James Young, a statistician at the University Hospital Basel, who led the study.
"Our results show that is not a very good strategy."
Moderating antibiotics, which are useless against viruses, is critical because overuse of drugs is contributing to the rapid rise of drug-resistant bacteria, he added.
"The underlying idea is the increasing resistance of bacteria to antibiotics," Young said in a telephone interview. "That is fundamentally the problem, which means we need to limit the use of antibiotics to when they are really needed."
Analysis of nine previous studies did not show why doctors are overpresribing, but a false belief that antibiotics may help if symptoms are long-lasting may be influencing doctors, he added.
"What we can show is that the length of symptoms reported by the patient does not reliably distinguish between viral and bacterial infection, Young said.
Instead doctors should watch and wait for longer to see if antibiotics are truly needed, because viral infections -- as well as bacterial ones -- can last for weeks, the researchers said.
In their analysis, the researchers looked at more than 2,500 people with sinus infection-type complaints who had been treated with an antibiotic or a placebo.
Then they set a statistical model using that data to show that doctors would have to give 15 people the drugs before an additional patient was cured. This showed the drugs were not likely to help fight sinus infection-type symptoms, Young said.
"Antibiotics are not justified even if a patient reports symptoms for longer than 7-10 days," the researchers said.