The Aging Physician

According to Health Canada, the proportion of Canadians aged 65 and over rose from 4.8% in 1921 to 12.3% in 1998.1 This cohort is projected to grow further before reaching a plateau at more than 20% of the population by the year 2026. This trend is not unique; similar predictions have been made for both industrialized and non-industrialized countries worldwide.2 Not surprisingly, a great deal of effort has been expended attempting to predict the impact of this demographic drift on the provision of health care.3 Less examined, however, has been the effect of this trend on health care providers themselves. Already in Ontario, Canada, however, one in four family practitioners and one in three specialists are over 55 years of age.4 While the rate of physicians' retirements has been increasing, these older physicians are going to become an ever-more-valuable resource as the ratio of physicians to population declines.5 Most of the medical education research that has used age as an independent variable has been performed in the context of physician-review programs. This literature suggests that aging induces cognitive changes in the way that diagnosticians approach clinical cases. There are discrepant findings, however, in terms of whether clinical performance improves or declines with aging. In this paper we systematically examine the small amount of evidence available in medical education that highlights the issue of aging and attempt to reconcile contradictory findings by drawing on the much larger psychological literature on pre-senile aging. Finally, we identify some of the specific implications for continuing education. Method Medline, ERIC, and the Research and Development Resource Base in Continuing Medical Education were used to search for articles focused on physicians' competence, physician assessment, and continuing competence. “Age” was used as a keyword in all searches and articles were included if they made reference to the relationship between age and performance. After a series of articles had been identified, the reference lists were examined and experts in this field were consulted to find relevant papers that had been missed. In parallel, a similar search was performed using PsychLit to identify articles that focused on age-related changes in cognitive processing. Articles were excluded if they focused on clinical conditions unless they allowed insight into the psychological mechanisms affected by pre-senile aging. Results The Negative Relationship between Age and Performance Since the 1970s, physician review programs have begun to flourish. Much of this work has been performed in Canada,6,7 but other countries, including England8,9 and the United States10,11 have also turned to assessments of this type as a way to ensure physicians' competence and advocate performance enhancement. While it is only one example of a variety of strategies that have been implemented, the Physician Review and Enhancement Program (PREP), based at McMaster University, typifies programs of this nature by using a battery of assessment tools to evaluate the abilities of practicing physicians.12,13 The process has evolved over the years, but the current battery consists of a multiple-choice-question test of medical knowledge, encounters with four standardized patients, and chart-stimulated recall. Skills evaluated with the standardized-patient encounters include communication, diagnosis, and data gathering. During chart-stimulated recall, the physician's own charts are reviewed and used as the basis for discussion between the assessors and the physician being assessed. This phase is meant to test problem solving, patient-management skills, and record-keeping practices. PREP evaluations are currently based primarily on referrals received from quality assurance committees operating within the College of Physicians and Surgeons of Ontario (CPSO),14 but during the validation phase of the program PREP also evaluated a criterion group of randomly selected physicians.15 Attempting to identify predictors of competence, Norman et al. entered a series of variables into a regression analysis and discovered that age was most predictive of three variables (the other two being Canadian versus foreign education and certification status) that significantly predicted performance.15 Older physicians performed less well than did younger physicians. Further (unpublished) analyses of these data confirm that this negative relationship is not an artifact of including CPSO-referred physicians in the study sample; the correlation between age and performance was stronger in the criterion group (r = -.50) than in the CPSO-referred group (r = -.36). More recent work shows this trend is not directly linked to neuropsychological impairments. Turnbull et al. administered a neuropsychological test battery on 27 physicians at the end of the regular PREP testing.14 The correlation between age and performance was strong (r = -.57) and became even stronger after removing from the analysis the 13 physicians who scored in the moderate-to-severe range on any of the neuropsychological tests (r = -.80). This inverse relationship between age and competence is consistent with previous work by McAuley and Henderson,16 who audited the practices of 391 randomly selected physicians, and with Norcini et al.'s17 analysis of the knowledge bases of practicing internists using the American Board of Internal Medicine's (ABIM) recertification exam, as well as with more recent work by Sample et al.,18 who examined patient-management skills using a computer-based case simulation. A problematic omission, however, if remediation is to be effective, is an answer to what is causing this inverse relationship. One possibility, supported by the work of Day et al.,19 is that older practicing physicians are less likely than are their younger colleagues to have up-to-date knowledge bases. Scores achieved on the ABIM recertification examination increased as the time since residency decreased when questions tested medical knowledge that had changed over the preceding 30 years, but showed no effect of the time since residency when questions tested medical knowledge that had been stable over the same period of time. While this is a seemingly straightforward explanation for the inverse relationship observed between age and competence, it does not appear to be sufficient. More recent work by Caulford et al.20 suggests that the nature of the problems encountered by failing physicians extends beyond a reduced tendency to assimilate new knowledge. Using the written reports generated for the PREP program, two assessors were asked to identify the specific deficiencies noted for each physician's performance. These deficiencies were categorized as problems of knowledge, history taking, problem solving, physical examination, patient management, communication skills, and record keeping. In addition to knowledge deficits, however, the identified deficiencies occurred across all eight categories of problems. Interestingly, for reasons that will become clear shortly, the most prevalent errors identified within many of the categories tended to be errors that would be expected to correlate with premature closure; the interviews tended to be abrupt with many interruptions, history taking was not comprehensive, data gathering was incomplete, important management strategies were not considered, and important details were left out of patient records. These results could, understandably, lead to pessimism regarding the ability of older physicians to practice medicine. However, there is an aspect of diagnostic practice that has been shown to improve with age, thereby yielding (a) further insight into the psychological mechanism whereby competence declines and (b) optimism regarding the potential to tailor continuing education efforts to the specific abilities/deficiencies of individual clinicians. The Positive Relationship between Age and Preliminary Diagnostic Accuracy The inverse relationship between age and performance seems counter-intuitive given the emphasis that most educators place on experience. Physicians who have been practicing longer have more experience and, as a result, should be better positioned to make accurate diagnostic decisions. This claim is especially central to the nonanalytic instance-based frameworks that have been proposed as models of medical knowledge.21 These frameworks argue that diagnosis is based, in part, on a rapid and unconscious matching of current patients to previous clinical encounters.22 The greater the number of cases one has seen, the more prior examples one should have available to draw upon. Consistent with this framework, diagnostic accuracy in the context that would be expected to elicit decisions based primarily on nonanalytic processes has been shown to increase with age. To examine the influence of experience on the generation of diagnostic hypotheses based solely on contextual factors, Hobus et al.23 presented research participants with short case histories consisting of a patient's picture, previous disease history, and presenting complaint. Family doctors produced 36% more correct hypotheses (12.11/32) than did medical students (8.88/32). When this procedure was repeated with 28 physicians whose years of experience ranged from four to 32, a strong positive correlation was found between experience and diagnostic accuracy (r = .68).24 This is noteworthy because previous work has shown that the accuracy of the first hypothesis is predictive of the accuracy of the final diagnosis,25 and a negative correlation has been observed between “accuracy” and “time required to raise diagnostic hypotheses.”26 These findings run counter to those mentioned in the preceding section. Physicians' diagnostic skills seem to improve with age, at least when the diagnostic information available is minimal. The important question then becomes “Why are older physicians more likely to be labeled incompetent by physician-assessment programs when they are better at generating diagnostic hypotheses based on contextual information alone?” A potential explanation is that as individuals age, nonanalytic diagnostic strategies remain strong (allowing the positive relationship between years of experience and accuracy of early hypotheses), but the use of analytic confirmation strategies declines (causing older physicians to score less well when dealing with conflicting data within comprehensive patient descriptions). A less complicated answer to the question posed would be that older physicians are better diagnosticians, but they (a) exert less effort toward the testing procedures utilized in review programs, or (b) have deteriorated testmanship skills as a result of having been out of school longer than younger colleagues. These possibilities seem unlikely. First, given the threat of losing a license to practice medicine, any physician who is called to a PREP review has tremendous motivation to perform at his or her highest level (even though the physician is unlikely to be happy doing so). Second, Day et al.19 observed that older physicians perform just as well as younger physicians on examinations as long as the questions are directed at knowledge that has not changed since they were trained. Still, the general point remains that age is confounded with many other variables when studied in the context of physicians' performances. To avoid these complications, the rest of this paper examines this issue by reviewing the psychology literature on aging in the hope that it will yield insight into (a) diagnostic decision making, (b) medical expertise, and (c) remediation strategies that might be considered for failing physicians. To set the context, a brief review of the literature on diagnostic expertise is first presented. Models of Diagnostic Reasoning Beginning in the late 1970s, thanks in large part to the work of Elstein, Shulman, and Sprafka,27 researchers in the field of medical education began to switch their views of diagnostic expertise from one in which problem-solving skills were emphasized to one in which the mental representation of medical knowledge became to et was the of diagnostic that when with a new physicians a set of hypotheses that they use to test the data presented. 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These might seem but it has been shown that as as have a greater effect on cognitive in older than in a more changes might be made to diagnostic the on that of diagnostic age-related in this is taking to older physicians might an important and that only showed no in performance with aging suggests that and practice might to be the to the of aging. This result, with the current suggests that practice should more on the analytic of medical diagnosis, as nonanalytic seems to remain the way to practice strategies might to be a but continuing education efforts should be toward Education and the current review the of physician-review and programs. While the of to be in any age-related increase in the on nonanalytic of knowledge will the physicians will have in when their skills are a result, review of physicians' performance is because motivation to in the aspect of PREP will be the individual remediation that (a) his or her performance is and (b) a specific diagnosis be to the