In this national study of Medicare patients, readmission rates neither improved nor worsened in association with ACGME duty hour reform. Any potential adverse consequences of the reform on continuity of care did not lead to observable changes in readmission rates for either medical or surgical patients. These findings were robust to the use of composite measures of readmission and mortality, changes in patient selection criteria, and alterations in severity adjustment.
We had hypothesized that readmission rates would increase in teaching hospitals following the duty hour reform because the increased frequency of handoffs would adversely affect continuity of care during index admissions. As a result, quality of care, and in particular effective discharge planning, would suffer. The link between readmission rates and the quality of hospital care has been debated12,36
. But recent work has pointed to the role of inadequate discharge planning and poor coordination of post-discharge care in readmissions11,18
. In addition, several trials of improved services around the time of patient discharge have reduced readmission rates37–39
The fact that readmission rates did not increase in teaching hospitals in the 2 years after the reform is encouraging; however, there are several other possible explanations for our findings. First, physician familiarity with patients at discharge may have minimal influence on the overall quality of the discharge process and therefore on the likelihood of readmission. Second, there are other factors that are part of the care transitions process and that might influence the risk of readmission, such as adequate social support and timely primary care follow-up40,41
. But the extent to which factors like these can be ensured by inpatient physicians, regardless of the level of their continuity of care, may be somewhat limited. Third, disruptions in continuity of care caused by the work hour rules may have been mitigated by alternative work force resources, such as increased presence of attending physicians. Fourth, residents are still permitted to work 30 consecutive hours, allowing them to participate in the morning discharge process. Fifth, the deleterious effects of increasing care handoffs may have been offset by the beneficial effects of reducing resident fatigue. Lastly, lack of compliance in the first year of the duty hour rules has been reported and would have undermined the reform’s effect on outcomes42
Our study is the first to examine the association between duty hour reform and hospital readmissions on a national scale. Two prior studies reported no change in readmission rates, but these analyses were limited to single institution experiences43,44
Our results add to the evidence that the reform in 2003 did not generally improve or worsen patient outcomes. Some critics have argued that the regulations, and resulting disruptions in continuity of care, would worsen patient outcomes. These data suggest that outcomes neither suffered as feared, nor improved as intended, after the reform. The fact that the reform has, to date, failed to accomplish one of its original objectives (to improve outcomes) should be factored into current deliberations on how to refine or extend the regulations45
Our study has limitations. We only evaluated Medicare fee-for-service beneficiaries, and therefore the results may not be generalizable to other populations. As with any observational study of this type, there may be unmeasured confounders. However, by comparing outcomes over time within each hospital, in more versus less teaching-intensive hospitals, potential bias from unmeasured cofounders is diminished. Our ability to adjust for differences in the severity of illness (i.e., risk of readmission) using administrative data is limited, but our difference-in-differences analysis essentially treated each hospital as its own control, factoring out inter-hospital differences in ICD-9-CM coding practices and severity of illness that were consistent over time.
In conclusion, our study showed that the ACGME duty hour rules had no systematic impact on readmission rates among Medicare fee-for-service patients admitted for major medical conditions or surgical procedures. Despite this finding, potential future disruptions in continuity of care resulting from further contemplated duty hour reform remain a valid concern46
. Our findings may provide reassurance that recent reforms have not had an adverse effect on quality of care, but they also underscore the importance of continued monitoring to identify which approaches to duty hour regulation are most likely to improve patient outcomes in the future.