The probability of PSA testing was highest among men aged 60 to 64 years (7.1%) and remained relatively constant with increasing age, until age 80 years when the probability declined to 3.1% Table 1. Among those aged younger than 50 years, black men were 3.4 times more likely than white men to have a PSA test, but the probability did not differ later in life Table 2. For visits by men aged younger than 50 years, however, 63% of the PSA tests were for white men.
We hypothesized that visits by men with lower urinary tract symptoms, a diagnosis of BPH, and for a general medical examination would be associated with more PSA testing. We found higher probabilities of testing in men with lower urinary tract symptoms compared with those without (11% vs 3.8%, P<.01), much higher probabilities in men with a diagnosis of BPH than those without (38% vs 3.0%, P<.001), and higher probabilities during a general medical examination than routine visits (13% vs 3.0%, P<.001). The observed PSA testing patterns by age and race persisted when we stratified visits by these characteristics. In particular, rates of PSA testing remained relatively constant until a patient was older than 80 years. Also, the high frequency of PSA testing in older men was not simply a matter of increased incidence of BPH or lower urinary tract symptoms Table 1.
Discussion
Although the 1997 American College of Physicians (ACP) clinical guideline on prostate cancer screening stated that men aged 50 to 69 years will benefit most if prostate cancer screening ultimately proves effective and the official clinical guideline of the American Academy of Family Physicians (AAFP) recommended counseling men aged 50 to 65 years about the known risks and uncertain benefits of screening for prostate cancer, we found that half of all PSA testing by primary care physicians in 1995 and 1996 was for patients whose ages made them less likely to benefit. The relatively high rates of PSA testing in men aged 70 years and older (even after excluding men with BPH or lower urinary tract symptoms) implies, in part, that primary care physicians may not have been sensitive to patient age when making their decisions about ordering a PSA test. The rate of PSA testing did not decline until patients aged 80 years, yet at 3.1% of visits it was still high considering the greater risk of competing causes of mortality in these men, as well as higher rates of treatment complications and a shorter time span for any potential benefit from prostate cancer screening.
Although the American Cancer Society and the American Urological Association have recommended that clinicians begin screening high-risk men (black men and men with a family history of prostate cancer) at age 40 years, the more recently released ACP clinical guideline did not recommend screening high-risk men any differently, because of the lack of direct and indirect evidence quantifying the value of earlier or more aggressive screening. We found that among men aged younger than 50 years, black men were more than 3 times more likely than white men to have PSA testing. This observation may suggest that during our 1995 and 1996 study period primary care physicians were following the recommendations of the American Cancer Society or those of the American Urological Association. Although early PSA testing in white men may have been because of positive family history, that particular risk factor could not be determined using NAMCS data.
There have been recent efforts to show that the practice patterns of PSA testing may not be optimal. Our results from a nationally representative sample of primary care physicians from varying disciplines add to the data from previous studies on the use of PSA testing that have shown that a substantial proportion occurs among men whose ages make them less likely to benefit from screening.
Limitations
Our findings must be interpreted with caution because the cross-sectional nature of the NAMCS data does not allow us to follow the care provided to individuals over time. Nevertheless, these data provide the opportunity to analyze the office practices of physicians across the nation during a typical workweek. Also, the national figures that we report are extrapolated from a sample of visits to study physicians. That extrapolation, however, is in accordance with the weighting and statistical aggregation processes provided by the National Center for Health Statistics. Additionally, the episodic aspect of PSA screening means that our rates in older men may be underestimated. Because older men visit their physicians more frequently, they have more opportunities to be screened and may be less likely to be screened at any given visit. Finally, our focus on the PSA screening controversy in older men does not imply a lack of controversy in screening younger men.