The debate about who should care for patients with HIV infection or other chronic diseases often focuses on specialty training. This focus fails to account for disease-specific experience and the knowledge and skills that physicians might acquire through such experience and other clinical or educational activities. Our study is the first that we are aware of to provide national data on the relationships between specialty training and specialization, and how they relate to physician knowledge and selected physician behaviors. We hypothesized that expertise in the treatment of a particular condition would be most related to both specialty training and specialization, but that specialization, as primarily measured by experience, would be the most important factor.
These results confirm our hypotheses in a nationwide representative sample of physicians caring for adults with HIV infection. Among generalist physicians, expertise was strongly associated with caseload, knowledge, referral rates, and rates of participation in CME activities. We found no important difference between physicians trained in infectious diseases and general physicians who consider themselves experts in HIV care on caseload and attendance at local and national meetings. Infectiousdiseases–trained physicians, however, had slightly higher HIV-related knowledge scores and referred less often. In multivariable models that controlled for caseload and self-assessed expertise, caseload was the most important predictor of knowledge scores. This suggests that interest and involvement in HIV care by a physician, as manifested by caseload, keeping up with the literature, and attending meetings, are related to disease-specific expertise, regardless of specialty training.
Other studies have shown that specialists are usually more knowledgeable than generalists about diagnostic techniques13,14
and efficacious therapies.15–20
In addition, when processes of care are examined (using chart reviews or patients' reports), for acute myocardial infarction (MI),15,21
specialists tended to provide care deemed appropriate at higher rates than did generalists. While ID physicians in our study had slightly higher knowledge levels and different behaviors than generalist HIV experts, it appears that physicians not trained in ID can, by virtue of interest, clinical experience, CME activities, and other methods of self-education such as reading medical journals and newsletters, develop similar levels of HIV expertise.
We found that generalists who do not claim to have expertise in HIV refer more than generalists who do have expertise. As expected, physicians with training in infectious diseases had the lowest rate of referral for the 5 clinical scenarios presented. While we cannot examine the appropriateness of these referrals, one might assume that higher rates of referral are an appropriate response for nonexpert physicians and that this does not indicate lower quality or inappropriate care. Several studies of acute MI have shown the value of specialists and generalists working together in consultative relationships,28
and collaborative management has clearly been shown effective in the treatment of depression.29
In addition, constraints imposed by the health care delivery system might also contribute to lower rates of referrals for ID specialists, particularly for patients who require approval of referrals from primary care physicians.
Kitahata et al. found that AIDS patients in the Group Health Cooperative treated by more experienced clinicians (defined as >5 cases) had lower mortality, as compared with patients treated by other clinicians.30
That study, however, was conducted before the advent of newer therapies and in a single organization where most of the physicians were family practitioners with very low patient volumes. Turner et al. demonstrated that patients with HIV infection cared for by generalists were more frequently hospitalized, and Markson et al. showed that generalists were slower to adopt the use of zidovudine.31,32
In addition, Curtis et al. and Paauw et al. suggest that generalist physicians have fewer skills than do specialists in diagnosing HIV-related complications, including recognizing HIV-related skin conditions and diagnosing Pneumocystis carinii
These studies, however, only examined formal training and were not able to account for HIV-specific experience and interests. Similarly, studies in cardiology21,35
and other specialties36
have also focused only on formal training. More recently, in a national survey, Stone et al. demonstrated that both training in infectious diseases and HIV experience were associated with prescribing appropriate antiretroviral regimens. That study, however, included physicians who were not necessarily the principal physicians for patients with HIV infection. Their findings were not significant when the analysis was restricted to physicians who would not refer patients for the management of HIV.37
Our study has several limitations. First, we do not know if the knowledge scale we used predicts care quality, and we do not have external criteria to assess the extent to which absence of knowledge will lead to poor care. However, nationally recognized experts selected questions that they thought reflected knowledge necessary to provide state-of-the-art care. Extensive pretesting that included groups of both HIV specialist physicians and generalist physicians with no particular expertise in the treatment of HIV infection demonstrated that the scale was able to discriminate between these 2 types of physicians. Second, as with all surveys, we rely on self-reports for our measures of specialty training, experience, and expertise. We see no reason, however, why error in reporting would tend to bias the associations we examined. Third, HCSUS did not include patients in prisons or the military and patients not receiving care. This is, however, the only nationally representative population of HIV-infected patients that we are aware of, and these patients identified our physician sample. We believe that our results can be generalized to physicians caring for patients with HIV infection in the United States. One additional caveat, however, is that HIV/AIDS may be atypical when compared to other chronic diseases in that when HIV first emerged, care was not uniformly embraced by ID specialists and was often delivered in community settings by generalists physicians. In the current environment, it might be more difficult for a non–ID-trained physician to develop similar expertise in HIV-related care. This would suggest, however, that in order to establish competency among current internal medicine residents, training programs should involve residents in the outpatient care of HIV-infected patients in settings where they can be supervised by experts in HIV-related care.
In summary, our results suggest that if we are to understand better the factors underlying reported associations between either specialty or volume and quality of care and/or outcomes, we should study both formal training and experience with a particular condition. Our data strongly suggest that general physicians are able to develop condition-specific knowledge similar to that of physicians with specialty training if they have a substantial case load and make an effort to stay current in a particular area. Specifically, we recommend that in future studies of HIV care, physicians be classified according to HIV caseload and whether they consider themselves experts in HIV care, in addition to classification by formal training. If there is concern that the latter type of measure is too subjective, other indicators, such as attendance at HIV clinical meetings, could be used. It remains to be determined whether these findings can be generalized to the care of patients with other chronic conditions. Further studies also are required to assess whether such knowledge translates into appropriate clinical practices and subsequent good outcomes. It will also be important to know if contextual factors, such as practicing with other specialists, modify the relationships described here.