This study was the first to report the outcomes of a Korean AMU hospitalist model with additional adjustments for patient-related clinical factors. We found lower IHM and ICU admission rates and shorter LOS and ED waiting times with AMU hospitalist care compared to non-hospitalist care. The same trend was observed in the subgroup and multiple regression analyses. However, there was no significant difference in the re-admission rates between patients cared for by hospitalists and those cared for by non-hospitalists
These results suggested that adequate, rapid management by hospitalists in the early phase of an acute illness and their efficient operation of the AMU have contributed to improved patient outcomes. The strength of our AMU care is the direct, real-time communication among variously trained team members, which facilitated making appropriate, rapid treatment decisions for patients with acute conditions . The AMU at our institution was different from typical emergency short-stay units operated by emergency physicians, mainly because the AMU follows these essential principles: intensive, active care, multi-disciplinary teamwork, and rapid diagnostics and therapy .
Previous studies that investigated the impact of AMU or hospitalist care have reported that IHM was reduced with hospitalist care [7, 8, 10, 21–28]. Contrary to those studies, another report found no significant difference in mortality between patients treated by a hospitalist and those treated by a non-hospitalist [29–34]. Moreover, a recent Korean study found no difference in IHM between hospitalist and non-hospitalist care in the integrated medical model .
Although those results were conflicting, in our institute, AMU hospitalist care was more effective than non-hospitalist care in reducing patient mortality. Our findings provided evidence that a hospitalist-run AMU was an effective model that significantly reduced IHM among patients with acute medical needs. This study also demonstrated that the existing British acute medicine model was effectively transformed into a Korean AMU model.
Few studies have reported ICU admission rates in AMU care. One study on a surgical co-management model, which mainly focused on patients that required surgery, found a significant reduction in the ICU admission rate in the hospitalist group , compared to the non-hospitalist group. Other studies have reported no significant difference the ICU admission rates between the two types of care [36–38]. However, in our study, the ICU admission rate decreased significantly with AMU hospitalist care. This finding implied that hospitalists in the AMU effectively treated patients with acute medical needs, and greatly contributed to stabilizing their conditions without ICU admission. This result showed that the new, effective AMU hospitalist care in Korea could reduce ICU admission through efficient, high-quality treatment for patients that require acute medical care.
Most studies on acute medicine have reported that hospitalist care could reduce LOS compared to non-hospitalist care [7–10, 21–23, 30, 31, 33, 34, 39–47]. In contrast, others have found that hospitalist care resulted in longer LOS or did not significantly affect LOS [32, 48, 49]. Despite those conflicting results, in our institute, AMU hospitalist care reduced the total LOS, compared to care from non-hospitalists. Recently, another study reported that hospitalist care within the integrated medical model of Korea showed a reduction in LOS, particularly in patients with multiple comorbidities . According to that study, patients that received hospitalist care had shorter LOS, for several reasons. One reason was that the hospitalists were better trained than residents; consequently, they could manage diseases from more perspectives, which increased the likelihood of resolving the condition . That finding suggested that Korean hospitalist care might significantly shorten LOS, regardless of the type of care model applied.
Some studies showed that AMU hospitalist care significantly shortened the ED waiting time, compared to non-hospitalist care [7–9, 23]. Consistent with previous studies, in our institution, AMU care also reduced the ED waiting time. This result might be explained by an increase in the bed turnover rate and an alleviation of delays caused by waiting inpatients.
In our study, AMU hospitalist care was not associated with a significant difference in unscheduled re-admissions. Previous studies showed that hospitalist care led to significantly lower re-admission rates, compared to non-hospitalist care [10, 21, 22, 29, 39, 48, 50]. Others found no significant difference in the re-admission rate [30, 32–34, 40–44]. Those results suggested that the re-admission rate might depend on the type of hospitalist care model applied, disease-related factors, and the hospitalist's roles. Shu et al. (2011) reported that, when a hospitalist provided post-discharge transitional care by telephone to discharged patients, the re-admission rate was significantly reduced . Some studies have found that an AMU significantly reduced the re-admission rate , but most studies on the effects of acute medicine found no effect of hospitalist care on the rate of unscheduled re-admissions [42, 43]. In our institution, AMU hospitalist care was focused on the acute treatment of inpatients admitted through the ED; therefore, we did not expect a significant impact on the post-discharge readmission rate.
In summary, we provided evidence that AMU hospitalist care in a Korean tertiary care hospital reduced IHM, ICU admission, LOS, and ED waiting time.
Our study had some limitations: (1) it had a retrospective design, and it was limited to a single institution; (2) it was difficult to distinguish whether the effects on outcomes were due to the AMU setting or the care provided by the hospitalists; (3) we did not evaluate patient or staff satisfaction; and (4) we did not perform an economic evaluation, including the medical costs. Future studies are necessary to determine whether the introduction of the AMU will improve patient health in the long term, increase patient or staff satisfaction, and improve the cost-effectiveness of patient care.