This study is the first to evaluate differences in resource use for residents and attendings for ambulatory and hospital costs after controlling for patient demographic and clinical characteristics. After adjustment for case mix, resident patients have similar hospital costs but higher ambulatory costs. Higher ambulatory costs result primarily from more consultations and radiology tests obtained on resident patients than attending patients. Unadjusted total costs were compared between resident patients and attending patients; resident patients had almost double the cost. When adjusted, however, the total cost was about 7% higher for resident patients in comparison to attending patients. The performance of care according to HEDIS-like criteria did not differ.
Academic medical centers were 33% to 44% more expensive and other teaching hospitals were 14% to 20% more costly than nonteaching hospitals, ostensibly after adjustment for case mix and the direct costs of graduate medical education.1–3
The higher costs of teaching as opposed to nonteaching hospitals has been attributed to a teaching effect or academic programs per se and practice style as well as to the inexperience of residents.15
Most of the studies have focused on costs and care for inpatients16
; unmeasured case mix differences have also been suggested.17,18
In addition, researchers have sought to evaluate the cost and quality of care in light of physicians' training and specialties. 19–23
The teaching effect hypothesis is that an attending and a resident jointly caring for a patient generate more utilization than any single physician. However, two studies involving the introduction of residency programs into established emergency departments suggest that neither the use of tests nor the costs of care increased when attendings worked with residents instead of independently.24,25
Similar results have been reported with regard to family practice, internal medicine, and pediatrics residents.26,27
Differences in practice style have been hypothesized to drive resource utilization patterns. For example, differences between general internists and family physicians have been suggested to lead to different ambulatory utilization patterns28,29
; specifically, a technically oriented style of care has been suggested to increase total charges.30
Differences in inpatient charges have been attributed to variation in practice by attendings.31
Such variation has historically been linked closely to cost differences and physicians' propensities to hospitalize their patients32
as well as to physicians' decisions about how long a patient should remain in the hospital.31
However, only small amounts of resource use have been found to be attributable to differences in practice styles.33,34
One inevitable hypothesis is that residents' lack of experience leads to higher costs and lower quality, although there are studies to the contrary.26,27
For example, a recent study showed no difference in total charges, radiology charges, or laboratory charges between a family practice residency teaching service and a hospitalist group.35
Experienced physicians have been shown to use contextual information about the patients' age, gender, and risk factors to reach more parsimonious diagnoses.36
Ambulatory costs were 30% higher for resident patients, controlling for demographic and clinical factors, including comorbidity and whether patients were newly referred after hospitalization. The costs also rose with increasing visits. Whether this is experience or practice style is arguable, because these findings echo other studies of ambulatory resources showing that physicians who saw patients more frequently also ordered more tests and referrals and generated higher costs.37
Of note, there is remarkably little data about how often ambulatory patients should be seen, and consequently, residents may be given considerable discretion about follow-up intervals for patients.
On the ambulatory side, residents did not obtain more laboratory tests per visit than attendings, but they did obtain more radiology tests, especially magnetic resonance imaging and more consults per visit. It is tempting to suggest that controlling utilization of more expensive radiology tests in resident patients would reduce costs; however, efforts to use radiology consultations to reduce utilization, at least among inpatients, have not been effective.38,39
Although we did not have data about consultations for inpatients, the higher rates of ambulatory consultation in resident patients are especially striking and resulted in higher total costs and higher total costs per visit for resident patients. In the absence of directly relevant data or literature, we can only speculate that the increased consultations may reflect the residents' uncertainty coupled with the supervising attendings' reluctance to intercede on this issue. If so, then consultation rates may be reduced if supervising attendings become more directive in this regard. There is some evidence that consultations per se drive utilization; on the inpatient service, specialty consultations have been associated with increased length of stay.40
On the other hand, inpatient costs did not differ between resident and attending patients, but resident patients were hospitalized twice as often. In the current study, the total costs for resident patients were higher than for attending patients. Unadjusted comparisons indicate that the cost of the resident patients' care was nearly double that of the attending patients' care, while adjusted comparisons indicate that the cost of the resident patients' care exceeded that of attendings' by 9%.
Our study, in particular, was limited by several factors. First, the data on resource utilization which was prospectively assembled and retrospectively analyzed do not include either hospitalizations or tests ordered outside of New York Presbyterian Hospital. Therefore, if patients of residents or attendings were more likely to have care outside our setting, then resource utilization would have been underestimated in that group. We do not have data that allow us to estimate the potential magnitude of the missing data, nor the direction of bias, if it exists. Second, although the analyses were adjusted for important demographic and clinical characteristics, especially comorbidity, we may not have captured all of the important factors for the case mix adjustment. Third, the same attendings were involved in caring for their own patients and in supervising residents, thereby potentially limiting the practice decisions made by the two groups. An approach comparing resident patients with patients managed by other providers might provide more definitive contrasts.35
Fourth, attendings were better able to provide continuity for the patients than residents, an inherent problem with resident schedules. Fifth, because data were collected over a 12-month interval from December through November, house officers occupied two different postgraduate years during the study; the comparison of performance of different PGYs was problematic. Sixth, the data were collected over 10 years ago; it may not completely reflect current practice, as the attending-to–resident supervisor ratio is now lower in ambulatory settings.
Our results indicate that resident patients had higher costs than attending patients, but the differences would have been seriously overestimated without adjustment. On the ambulatory side, the larger number of procedures and consults ordered for resident patients appears to drive the higher costs. In conclusion, it costs about 7% more for residents to manage patients than attendings and the higher costs for resident patients resulted from higher ambulatory costs. Without adjustment, the total costs would have appeared almost twice as high.