Doctors should avoid routine urine testing of older patients with delirium when there are no clinical signs or symptoms of infection, concludes a Johns Hopkins Medicine team.

“Urine tests are often one of the first that doctors call for in these situations [but] just because it’s an easy test to obtain doesn’t mean it’s an appropriate test,” says study lead author Milad Memari, senior resident in internal medicine at the School of Medicine. “Our research indicates that patients who are elderly, delirious and unable to give their medical history may be more likely to suffer from the consequences of unnecessary testing and treatment.”

In their research, Memari and his colleagues reviewed previous studies by others that evaluated the practice of conducting urine tests in hospitals, specifically those for older people with delirium. From one of these studies, Memari’s team learned that 83% of nearly 3,000 patients in hospitals across the nation — including patients age 65 and older — were given antibiotic therapy based on urine cultures positive for bacteria even though the microbes may in fact have been harmless. Another investigation showed that more than a quarter (92 out of 343 patients, or 27%) received antibiotics when they did not have clinical signs of urinary tract infections, and they had suffered from harmful long-term consequences of these treatments that may have been unnecessary.

“If [elderly, delirious patients] don’t have symptoms or clinical signs consistent with infection, then their doctors should forego urinary testing to avoid complications from unnecessary antibiotic treatment, and as a result, longer hospitalizations, slower recovery times and poorer outcomes,” Memari says.

He notes that a large number of older patients grow bacteria in urine cultures but may not actually have urinary infections. The focus, he says, should be avoiding unnecessary testing to prevent treatment of bacteria that are a normal, healthy part of a patient’s urinary ecosystem. Also, the more a patient is treated for a urinary infection, the more likely that person will develop a resistance to antibiotics. In turn, this makes urinary infections harder to treat in future instances, and has contributed to increased antibiotic resistance in a highly vulnerable population, Memari says.

“When treating older populations, we have to remember the principle of ‘first, do no harm,’” says Memari, whose team’s study was published in the Journal of Hospital Medicine in July. “Our team hopes that this review of existing research will get a conversation started in hospitals across the country.”