Age, Sex of Physician Influence Inappropriate PSA Tests

BOSTON, July 9 -- Older male clinicians are more likely than others to order inappropriate prostate specific antigen (PSA) tests, researchers here said.

In a retrospective analysis of PSA testing in seven New England Veterans Affairs hospitals, about one in six tests was considered inappropriate -- usually because the patient was older than 75, according to a report in the July issue of Archives of Internal Medicine.

The causes of the age and sex differences remain unclear and require further investigation, said B. Price Kerfoot, M.D., of the Veterans Affairs Boston Healthcare System, and colleagues.

"It is possible that, as they age, male health care providers increasingly empathize with their older male patients over prostate cancer concerns," they said.

This "prostatempathy" may then lead to more aggressive screening, the researchers suggested.

The findings arise from the researchers' analysis of 105,765 male patients, who underwent a total number of 232,302 PSA tests between January 1, 1997 and October 1, 2004.

While there is debate over when PSA tests should be ordered, there is a strong consensus that they are inappropriate in men under age 40 or over 75, and none of the major clinical practice guidelines recommends that PSA screening be routinely performed in asymptomatic men younger than 40 years, older than 75 years, or with less than a 10-year life expectancy, even if the patient is in a group at high-risk for prostate cancer, the researchers noted.

Of the total tests ordered, they found that 37,483 (or 16.1%) were inappropriate, with 35,612 (or 15.3%) in patients over 75 and 1,871 (or 0.8%) in patients younger than 40.

Over the eight-year study period, 1,552 health care providers ordered the tests; 51.3% were men, 79.4% were physicians, 20.6% were nurses, nurse practitioners, or physician assistants. Of the physicians, 8.2% were urologists, and 53.4% were interns, residents, or fellows.

A univariate analysis of provider characteristics showed that inappropriate use of PSA testing was significantly elevated (at P<0.05) among urologists, male health care providers, and the health care providers who didn't order the test very often.

Compared with attending physicians, nurses, nurse practitioners, and physician assistants had significantly lower levels (again at P<0.05) of inappropriate screening. There was also significant variation among hospitals in the study.

In the multivariate analysis, the inter-hospital variation and the frequency of ordering tests remained significant, the researchers said.

The researchers also found a significant (at P=0.01) interaction between age and sex. The proportion of inappropriate PSA tests increased significantly (at P<0.001) with the age of male practitioners, but decreased with the age of female practitioners (at P=0.048.)

Specifically, male health care providers ages 46 through 50 were 9% more likely than female health care providers of the same age to screen inappropriately.

The proportion increased to 51% for those ages 51 through 55 and to 95% when providers were older than 55.

The study "substantiates that PSA screening is frequently performed counter to evidence-based guidelines," the researchers concluded. Better education -- both of patients and health-care providers -- would reduce inappropriate testing, they said.

One of the study's strengths is that it used a multi-hospital longitudinal database from a health-care system with limited patient turnover, the researchers said.