Exnovation of Low Value Care: A Decade of Prostate-Specific Antigen Screening Practices

Julie Bynum, MD, MPH; Honor Passow, PhD; Donald Carmichael, MDiv; Jonathan Skinner, PhD


J Am Geriatr Soc. 2019;67(1):29-36. 

In This Article

Abstract and Introduction


Objectives: To examine prostate-specific antigen (PSA) screening practice change in subgroups of men defined in guidelines and in various regions and to identify factors associated with change in screening practices.

Design: Observational study using serial cross-sections, 2003 to 2013.

Setting: National fee-for-service Medicare.

Participants: Men aged 68 and older eligible for prostate cancer screening.

Measurements: National PSA screening practices in men aged 68 and older from 2003 to 2013 and change in regional screening rates in men aged 75 and older.

Results: The PSA screening rate in men aged 68 and older was 17.2% in 2003, 22.3% in 2008, and 18.6% in 2013 (p < .001 for all differences); rates ended slightly lower than rates in 2003 only in men 80 and older. Racial disparities in screening became less pronounced over this period. In men aged 75 and older, change in regional screening rates varied widely, with absolute rates growing by 15 per 100 enrollees in some areas and declining by the same amount in others. Areas with high social capital, a measure associated with diffusion of new ideas, were more likely to decline; malpractice intensity and managed care penetration had no effect.

Conclusion: Studying Medicare enrollees over time, we found little reduction in PSA screening and even increases according to race and in some regions. The heterogeneous changes across regions suggest that consistent reduction in the use of low-value care may require change strategies that go beyond evidence and guidelines to include monitoring and feedback on performance.


There is a "pervasive asymmetry in human psychology" that makes it harder for healthcare workers to give up old clinical practices than to adopt new ones, even when they are revealed to provide low value.[1] Across disciplines, there is increasing interest in the idea of "exnovation," or the process by which practitioners turn away from an existing practice or process.[2–5] Screening for prostate cancer using the prostate-specific antigen (PSA) is an important example of evolution of practice in response to emerging scientific evidence.

After years of debate, in March 2009, two randomized controlled trials provided evidence that screening for prostate cancer using the PSA test offered at best modest benefits, particularly in aged 70 and older.[6,7] In 2010 and 2011, systematic reviews concluded that PSA screening provides no significant reduction in prostate cancer or overall mortality.[8,9] One concluded that the harms were frequent and moderately severe,[8] and the other found little evidence of harms.[9]

Before this period, guidelines for PSA screening repeatedly changed (Figure 1), converging on the notion that the value of PSA screening is low. For example, when proposing its latest update,[10–14] the U.S. Preventive Services Task Force (USPSTF) stated there is "a small net benefit for men ages 55 to 69 years, [but] the balance of benefits and harms in men remains close."[15] The guidelines are also nuanced, requiring complex estimations of benefit:harm ratios in subgroups of men who may not be well represented in trials. For example, the USPSTF and the American Urological Association have consistently recommended against screening men with a limited life expectancy, sometimes naming a specific age cutpoint,[16–21] and because of the greater risk of prostate cancer in black men, some guidelines recommend initiating screening earlier.[17,19,22]

Figure 1.

A history of clinical practice guidelines and evidence pertaining to prostate-specific antigen screening of asymptomatic men, including all U.S. Protective Services Task Force guidelines, publication of pivotal evidence, and selected other guidelines.

Changing guidelines were on a background of widely varying regional screening practices. Given disparate screening practices, it is not clear that practice change, even for the oldest men, for whom guidelines agreed, would occur uniformly across markets. Examining what happened in clinical practice over this period of evidence and guideline change provides an opportunity to understand the process of exnovation of low-value services.

Using PSA screening, we aimed to understand which factors influence practice change during a period when a decline in service use would be expected. First, we focused on national PSA screening in men aged 68 and older with fee-for-service Medicare from 2003 to 2013 and examine the influence of guidelines by assessing changes in likelihood of screening associated with factors directly mentioned in guidelines. Second, we focused on practice change across U.S. hospital referral regions (HRRs) for men aged 75 and older – for whom guidelines have been in agreement – to test whether practice variation declines and what contextual factors are associated with greater decline. We hypothesized that guidelines and the practice environment would influence the degree to which practitioners and patients would reduce their use of an existing practice in the face of converging evidence regarding effectiveness.