Early Rehospitalization After Kidney Transplantation
Early Rehospitalization After Kidney Transplantation
In this study of KT recipients over a 5-year period, early rehospitalization was a common event after transplantation, occurring in 32% of our cohort. This rate is consistent with previous studies of early rehospitalization events in the national KT patient population. Expert physicians were able to identify that a majority (>90%) of these hospitalizations were unplanned, and to consistently adjudicate the diversity of reasons for these early rehospitalizations by careful chart review. However, only a minority (9%) of these events had evidence of preventability by our criteria. While risk-adjustment models are currently implemented by Medicare to attempt to differentiate between rehospitalizations that result from high patient complexity and those that result from lapses in processes-of-care, our finding of a low rate of preventability suggests that early rehospitalization after KT may be problematic to implement as a quality-of-care metric.
Interestingly, KT recipients who were rehospitalized early had spent more time on the waiting list and had longer initial LOS during KT. At our center, transplant candidates are evaluated on a yearly basis after being added to the waiting list and we request constant communication with outside providers for updates on the health status of the candidates. Our evaluation process includes social worker assessments in addition to physician evaluation, and candidates are required to stay current with requested testing including cardiac clearance and cancer screening as appropriate. Candidates who do not meet these requirements are inactivated on the waiting list and further evaluated or de-listed when necessary.
Furthermore, patients who were discharged on a weekend day were more likely to be rehospitalized within 30 days. Per center protocol during the study period, once recipients were discharged from KT they were routinely seen by transplant clinicians including surgeons, nephrologists and nurse practitioners on Monday mornings for weekly follow-up appointments, with laboratory assessments occurring at least twice weekly in the first posttransplant month. Each recipient was also assigned to a transplant coordinator, with on-call coordinators available after hours and on the weekends. All coordinator communications were charted in the electronic medical record. Therefore, given that patients discharged on the weekend typically had the shortest time to first outpatient follow-up after KT, our finding that these recipients were more likely to experience early rehospitalization suggests that the weekend may represent a period of time when patients may be especially vulnerable to changes in health provider staffing that impact their transitions of care. If further multicenter studies confirm these findings, transplant centers may consider augmenting staffing and the oversight related to weekend discharges. Interestingly, advanced recipient age, considered a risk factor for other adverse outcomes following KT, was not associated with early rehospitalization.
Our expert physicians strongly agreed on reasons for early rehospitalization, as measured by the kappa statistic. We determined that, in addition to primary graft dysfunction, postoperative complications (including pain, bleeding and systemic thrombosis) and intravascular volume shifts are major causes of early rehospitalization. Our finding that infections are also an important reason for early rehospitalization is consistent with previous findings that KT recipients have a cumulative incidence of infections of >75% by 1 year after transplantation, with the highest risk in the immediate postoperative period. The diversity of reasons for rehospitalization suggest that efforts to reduce rehospitalization rates after KT should not focus on any single cause, but instead should address common pathways that lead to vulnerability during transitions-of-care (e.g. standardizing communication between providers, reducing time between follow-up visits, and improving patient education).
Adjudicating preventability of rehospitalization has proven a challenge in previous studies of general medicine patients and is not feasibly achieved using claims data alone. Using detailed chart review and an instrument with many choices for the reason for rehospitalization, our reviewers agreed strongly on reasons for rehospitalization (kappa = 0.68). Reviewers also agreed on the preventability of rehospitalization in 85% of cases. However, the discrimination of the kappa statistic is in part dependent on the number of choices raters are offered, and in our study, we offered only two categories of preventability (preventable or not). Also, because preventable rehospitalizations were rare events, the expected proportion of agreement was very high. The resulting kappa statistic indicated that the reviewers did not agree to a greater extent than predicted by chance alone. These results highlight the challenges of adjudicating preventability, and by extension rehospitalization, as a quality-of-care metric in KT recipients using only a retrospective approach, particularly given the diversity of reasons for rehospitalization. We acknowledge that our finding that only 9% of early rehospitalizations were preventable represents a conservative estimate because physician reviewers' assessments were limited by the variable quality and detail of clinical documentation. Notably, our method of determining preventability required that the physician adjudicator be able to identify a specific reason (e.g. a deficit in a process of care) why the rehospitalization event could have been prevented. Likely due to differences in methodology, our results contrast with the study using claims data by Goldfield et al that found that over 20% of rehospitalizations following KT were potentially preventable. Prospective studies are needed to fully explore this area.
In our study, early rehospitalization was associated with mortality but not with all-cause graft loss. Our findings suggest that early rehospitalization may signal unmeasured or unobserved recipient vulnerabilities, such as frailty, that independent of age and allograft quality are associated with mortality. Early rehospitalization could also act as a surrogate measure for factors that are otherwise difficult for clinicians to measure, such as severity of vascular disease, socioeconomic status, access to care, level of frailty or limited health literacy. These results are also consistent with previous studies in general medicine populations that have identified patient comorbidities, previous healthcare utilization and initial hospitalization acuity as strong predictors of 30-day rehospitalization. Patients identified as vulnerable from early rehospitalization events may benefit from additional or different forms of monitoring (e.g. more frequent outpatient appointments, phone calls, laboratory checks).
This study has several limitations. A substantial limitation is the generalizability of these single-center results. While our institution's rehospitalization rate is similar to national rates, a recent study did suggest that there is considerable variability in these rates between centers, possibly representing differences in quality of processes-of-care. We compared our center to the national cohort of KT recipients and found that distributions of recipient age, gender, race and donor type were comparable. However, we acknowledge that just as the causes of early rehospitalization are diverse, the measures that will most improve outcomes may be equally diverse between transplant centers. Our center has identified a low rate of preventability based on observable processes-of-care but our results should be validated at multiple transplant centers. Also, while our thorough chart review process enabled adjustment for an extensive list of known, important confounders, we acknowledge that unmeasured confounders or effect modifiers (e.g. level of education, frailty) could prove important in understanding risk factors for rehospitalization. For example, it is possible that in some cases, unmeasured confounders such as lack of social support may necessitate that recipients are discharged on the weekend. Furthermore, the retrospective nature of chart review only allows a limited assessment of the preventability of these rehospitalizations. Despite the fact that our reviewers agreed strongly on reasons for rehospitalization, reviewers only agreed on the preventability of rehospitalization in 85% of cases. It is possible that charted information that is necessary for physicians to ascertain concrete, preventable causes of rehospitalization was systematically missing, but if this were the case, this lack of charted details is a further argument that prospective multicenter studies are needed to completely ascertain systems-based reasons for these diverse events. Additionally, certain recipient risk factors previously found to be predictors of early rehospitalization (e.g. history of cancer, cerebral vascular disease, arrhythmia and chronic obstructive pulmonary disease) were not included in this analysis. Given the retrospective nature of the study, we also acknowledge the potential for information bias, though it should not pose a substantial problem for the ascertainment of the primary outcome of early rehospitalization. Most early rehospitalizations are extensively documented by the hospital system, and our single-center study had the advantage of the convention that transplant recipients overwhelmingly return to their transplant centers for medical care in the immediate postoperative period. In addition, our KT recipients are instructed to maintain close contact with their transplant coordinators and physicians, which would certainly be expected in the case of rehospitalization in the 30 days after KT. With meticulous review of medical records including all transplant coordinator communications, we are confident in our ascertainment of early rehospitalization events.
Early rehospitalization is common following KT and these events are increasingly scrutinized as a potential quality-of-care indicator. Our rigorous chart review process has identified the diversity of causes for these events and suggests that a minority of these events were preventable. Our retrospective study is, to our knowledge, the first chart review of KT patients who have experienced early rehospitalization seeking to adjudicate preventability. Prospective multicenter studies with detailed recipient-level data are needed to further identify recipient factors and modifiable center-level factors that may potentially reduce the rate of rehospitalization in this vulnerable and unique patient population.
Discussion
In this study of KT recipients over a 5-year period, early rehospitalization was a common event after transplantation, occurring in 32% of our cohort. This rate is consistent with previous studies of early rehospitalization events in the national KT patient population. Expert physicians were able to identify that a majority (>90%) of these hospitalizations were unplanned, and to consistently adjudicate the diversity of reasons for these early rehospitalizations by careful chart review. However, only a minority (9%) of these events had evidence of preventability by our criteria. While risk-adjustment models are currently implemented by Medicare to attempt to differentiate between rehospitalizations that result from high patient complexity and those that result from lapses in processes-of-care, our finding of a low rate of preventability suggests that early rehospitalization after KT may be problematic to implement as a quality-of-care metric.
Interestingly, KT recipients who were rehospitalized early had spent more time on the waiting list and had longer initial LOS during KT. At our center, transplant candidates are evaluated on a yearly basis after being added to the waiting list and we request constant communication with outside providers for updates on the health status of the candidates. Our evaluation process includes social worker assessments in addition to physician evaluation, and candidates are required to stay current with requested testing including cardiac clearance and cancer screening as appropriate. Candidates who do not meet these requirements are inactivated on the waiting list and further evaluated or de-listed when necessary.
Furthermore, patients who were discharged on a weekend day were more likely to be rehospitalized within 30 days. Per center protocol during the study period, once recipients were discharged from KT they were routinely seen by transplant clinicians including surgeons, nephrologists and nurse practitioners on Monday mornings for weekly follow-up appointments, with laboratory assessments occurring at least twice weekly in the first posttransplant month. Each recipient was also assigned to a transplant coordinator, with on-call coordinators available after hours and on the weekends. All coordinator communications were charted in the electronic medical record. Therefore, given that patients discharged on the weekend typically had the shortest time to first outpatient follow-up after KT, our finding that these recipients were more likely to experience early rehospitalization suggests that the weekend may represent a period of time when patients may be especially vulnerable to changes in health provider staffing that impact their transitions of care. If further multicenter studies confirm these findings, transplant centers may consider augmenting staffing and the oversight related to weekend discharges. Interestingly, advanced recipient age, considered a risk factor for other adverse outcomes following KT, was not associated with early rehospitalization.
Our expert physicians strongly agreed on reasons for early rehospitalization, as measured by the kappa statistic. We determined that, in addition to primary graft dysfunction, postoperative complications (including pain, bleeding and systemic thrombosis) and intravascular volume shifts are major causes of early rehospitalization. Our finding that infections are also an important reason for early rehospitalization is consistent with previous findings that KT recipients have a cumulative incidence of infections of >75% by 1 year after transplantation, with the highest risk in the immediate postoperative period. The diversity of reasons for rehospitalization suggest that efforts to reduce rehospitalization rates after KT should not focus on any single cause, but instead should address common pathways that lead to vulnerability during transitions-of-care (e.g. standardizing communication between providers, reducing time between follow-up visits, and improving patient education).
Adjudicating preventability of rehospitalization has proven a challenge in previous studies of general medicine patients and is not feasibly achieved using claims data alone. Using detailed chart review and an instrument with many choices for the reason for rehospitalization, our reviewers agreed strongly on reasons for rehospitalization (kappa = 0.68). Reviewers also agreed on the preventability of rehospitalization in 85% of cases. However, the discrimination of the kappa statistic is in part dependent on the number of choices raters are offered, and in our study, we offered only two categories of preventability (preventable or not). Also, because preventable rehospitalizations were rare events, the expected proportion of agreement was very high. The resulting kappa statistic indicated that the reviewers did not agree to a greater extent than predicted by chance alone. These results highlight the challenges of adjudicating preventability, and by extension rehospitalization, as a quality-of-care metric in KT recipients using only a retrospective approach, particularly given the diversity of reasons for rehospitalization. We acknowledge that our finding that only 9% of early rehospitalizations were preventable represents a conservative estimate because physician reviewers' assessments were limited by the variable quality and detail of clinical documentation. Notably, our method of determining preventability required that the physician adjudicator be able to identify a specific reason (e.g. a deficit in a process of care) why the rehospitalization event could have been prevented. Likely due to differences in methodology, our results contrast with the study using claims data by Goldfield et al that found that over 20% of rehospitalizations following KT were potentially preventable. Prospective studies are needed to fully explore this area.
In our study, early rehospitalization was associated with mortality but not with all-cause graft loss. Our findings suggest that early rehospitalization may signal unmeasured or unobserved recipient vulnerabilities, such as frailty, that independent of age and allograft quality are associated with mortality. Early rehospitalization could also act as a surrogate measure for factors that are otherwise difficult for clinicians to measure, such as severity of vascular disease, socioeconomic status, access to care, level of frailty or limited health literacy. These results are also consistent with previous studies in general medicine populations that have identified patient comorbidities, previous healthcare utilization and initial hospitalization acuity as strong predictors of 30-day rehospitalization. Patients identified as vulnerable from early rehospitalization events may benefit from additional or different forms of monitoring (e.g. more frequent outpatient appointments, phone calls, laboratory checks).
This study has several limitations. A substantial limitation is the generalizability of these single-center results. While our institution's rehospitalization rate is similar to national rates, a recent study did suggest that there is considerable variability in these rates between centers, possibly representing differences in quality of processes-of-care. We compared our center to the national cohort of KT recipients and found that distributions of recipient age, gender, race and donor type were comparable. However, we acknowledge that just as the causes of early rehospitalization are diverse, the measures that will most improve outcomes may be equally diverse between transplant centers. Our center has identified a low rate of preventability based on observable processes-of-care but our results should be validated at multiple transplant centers. Also, while our thorough chart review process enabled adjustment for an extensive list of known, important confounders, we acknowledge that unmeasured confounders or effect modifiers (e.g. level of education, frailty) could prove important in understanding risk factors for rehospitalization. For example, it is possible that in some cases, unmeasured confounders such as lack of social support may necessitate that recipients are discharged on the weekend. Furthermore, the retrospective nature of chart review only allows a limited assessment of the preventability of these rehospitalizations. Despite the fact that our reviewers agreed strongly on reasons for rehospitalization, reviewers only agreed on the preventability of rehospitalization in 85% of cases. It is possible that charted information that is necessary for physicians to ascertain concrete, preventable causes of rehospitalization was systematically missing, but if this were the case, this lack of charted details is a further argument that prospective multicenter studies are needed to completely ascertain systems-based reasons for these diverse events. Additionally, certain recipient risk factors previously found to be predictors of early rehospitalization (e.g. history of cancer, cerebral vascular disease, arrhythmia and chronic obstructive pulmonary disease) were not included in this analysis. Given the retrospective nature of the study, we also acknowledge the potential for information bias, though it should not pose a substantial problem for the ascertainment of the primary outcome of early rehospitalization. Most early rehospitalizations are extensively documented by the hospital system, and our single-center study had the advantage of the convention that transplant recipients overwhelmingly return to their transplant centers for medical care in the immediate postoperative period. In addition, our KT recipients are instructed to maintain close contact with their transplant coordinators and physicians, which would certainly be expected in the case of rehospitalization in the 30 days after KT. With meticulous review of medical records including all transplant coordinator communications, we are confident in our ascertainment of early rehospitalization events.
Early rehospitalization is common following KT and these events are increasingly scrutinized as a potential quality-of-care indicator. Our rigorous chart review process has identified the diversity of causes for these events and suggests that a minority of these events were preventable. Our retrospective study is, to our knowledge, the first chart review of KT patients who have experienced early rehospitalization seeking to adjudicate preventability. Prospective multicenter studies with detailed recipient-level data are needed to further identify recipient factors and modifiable center-level factors that may potentially reduce the rate of rehospitalization in this vulnerable and unique patient population.
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