August 30, 2015

They All Add Up

With so much attention rightfully devoted to big ticket items in medicine such as the new drug for hepatitis C that costs $1000 a pill or high tech devices such as the continuous flow left ventricular assist device, which costs on average about $200,000 to insert, not many people are talking about the little ticket items. But the reality is that spending a small amount per person on a huge number of people adds up to just as much—or maybe more—than spending an enormous amount  per person for just a few individuals. So I was very pleased to see a research letter in JAMA Internal Medicine about that lowly test, the urinalysis. 

I was pleased that the authors looked at the consequences of the rampant ordering of urine tests in people with no symptoms suggestive of either an infection in the bladder or kidneys or acute kidney dysfunction, the only circumstances in which urinalyses have been found to be meaningful. The reason, quite simply, that most urine tests are useless or, as the article suggests, actually harmful, is that the majority of older people have bacteria in their urine. What this means is that the injudicious ordering of a urine test will far more often produce a “false positive” result than a “true positive.”

It so happens that twice in one morning of seeing patients this week, I was asked to order a urine test for no good reason. To be fair, the well-meaning daughters of the patients who requested the test, quite insistently, I might add, thought it was with good reason. Their mothers were being diagnosed with dementia, a condition that had developed insidiously over a period of at least a year and probably several, and they were hoping I would identify a “reversible cause” of this otherwise progressive, ultimately fatal illness. Neither patient, however, had any symptoms to suggest a bladder infection: they did not have burning on urination, they did not have urinary frequency, they had no fever or flank pain. One lady was 96; the other was 91. Since the majority of elderly women have bacteria in their urine, I was concerned that if we got a sample from these two (no mean feat if we wanted a “clean catch” specimen, uncontaminated by bacteria from the surrounding skin and from stool), it would show bacteria. But if we did anything with the result—and what was the point of getting the test unless we were planning to treat the ladies in the vain hope that a course of antibiotics would cure their dementia—we would do little more than expose them to a risk of another problem such as clostridium difficile colitis, a potentially serious, occasionally lethal infection common in debilitated older people that typically results from killing off other bowel bacteria with antibiotics.

So what did the new study find? The authors looked at 403 consecutive adult patients admitted to the general medical service of a hospital in 2014 and 2015. They found that in this group, who somewhat surprisingly had a median age of 79, 62% had a screening urinalysis at the time of admission. Fully 84% of these individuals lacked any symptoms suggestive of a urinary tract infection. Of the asymptomatic patients who were screened with a urinalysis, 30% had a positive test. Of those with a positive test, 22% were treated with antibiotics.

Maybe this is actually reassuring: only 30% of asymptomatic patients had bacteria in their urine, not the 90% the authors quote from the literature. And only 22% of the asymptomatic patients with a positive test were given antibiotics, not everyone. 

The research letter in JAMA Internal Medicine leaves many questions unanswered. We don’t know why so many asymptomatic patients had a urine test ordered—perhaps the physicians believed that the fall or fainting episode that triggered the hospitalization was in fact caused by a bladder infection, which is conceivable, even if dementia (what my patients suffered from) is not. We don’t know what proportion of those who were needlessly treated developed complications because of the antibiotics they received. We can’t measure just how much the injudicious use of antibiotics in situations such as this contributes to the development of bacteria that are resistant to multiple antibiotics, bacteria that go on to cause real disease that is phenomenally difficult to treat. 

We do know that there are over half a million people age 65 and over hospitalized each year according to the National Hospital Discharge SurveyIf over half of them have an unnecessary test, and if a third of those tests are positive, and a fifth of those positive tests lead to potentially risky treatment, that’s still a lot of bad decisions. All those small ticket items add up, and we need to pay attention to the little decisions we make every day, not just to the big decisions we make once in a while.

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