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* From the School of Nursing (Drs. Daly, Douglas, and Kelley) and from the School of Medicine (Drs. OToole and Montenegro), Case Western Reserve University, Cleveland, OH.
Correspondence to: Barbara J. Daly, PhD, RN, School of Nursing, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH 44106-4904; e-mail: bjd4{at}case.edu
| Abstract |
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Study objectives: To test the effect of a DM program on hospital readmission patterns of chronically critically ill patients during the first 2 months after hospital discharge and to estimate the cost-effectiveness of the DM program.
Design: Randomized, controlled trial.
Setting: Academic medical center, extended care facilities, and participant homes.
Participants: Three hundred thirty-four consenting adults from one academic medical center who underwent > 3 days of mechanical ventilation and survived to hospital discharge.
Intervention: Two hundred thirty-one patients in the experimental group received care coordination, family support, teaching, and monitoring of therapies from a team of advanced-practice nurses, a geriatrician, and a pulmonologist for 2 months post-hospital discharge.
Measurements: Rehospitalization rate, time-to-first rehospitalization, duration of rehospitalization, mortality during rehospitalization, and associated costs.
Results: Patients who received DM services had significantly fewer mean days of rehospitalization (11.4; 95% confidence interval [CI], 9.3 to 12.6) compared with the control group (16.7 days; 95% CI, 12.5 to 21.0; p = 0.03). There were no other significant differences between experimental and control groups, although all measures of rehospitalization risk for the experimental group were in a positive direction. Total cost savings associated with the intervention were approximately $481,811 for the 93 subjects who were readmitted to the hospital.
Conclusions: Chronic critical illness may have a natural trajectory of continued morbidity following hospital discharge that is not affected by the provision of additional care coordination services. Nevertheless, given the high cost of rehospitalization and the additional burden it imposes on patients and families, interventions that can reduce the duration of rehospitalization are cost-effective and merit continued testing.
Key Words: chronically critically ill disease management long-term ventilation
| Introduction |
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Over the past decade, investigations have continued to examine long-term outcomes following prolonged stays in critical care units111213 and prolonged mechanical ventilation.1415161718 These descriptive, correlational reports have consistently documented the pattern of continuing morbidity and mortality among the CCI. A particular concern has been the high rate of hospital readmission in the first 6-month post-hospital discharge period, which is noted to be close to 40%.1419
CCI patients who survive lengthy stays in the ICU present many post-hospital discharge challenges to the health care teams who assume responsibility for their care. Extended care facility staff and primary care physicians are increasingly faced with assuming the responsibility for managing these complex patients, quickly gaining familiarity with the patients history and course of illness, and coordinating the continuing input from multiple medical specialists and health care providers. The primary purpose of our study was to evaluate the effect of adding disease management (DM) services to the usual care system on rehospitalization patterns among CCI patients in the first 2 months after their hospitalization.
| Materials and Methods |
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The study site was University Hospitals of Cleveland, a 950-bed tertiary care hospital associated with Case Western Reserve University. All of the patients who met the eligibility criteria during their hospitalization in any adult ICU of the study hospital were enrolled. Patients and family members were approached for consent to participate when it was clear that hospital discharge was expected within the next few days. The Institutional Review Board approval was obtained prior to data collection.
Between March 2001 and December 2004, research nurses screened all of the ICU patients for study eligibility. All of the study staff were trained in the use of the research instruments prior to data collection, and interrater reliability was monitored on a quarterly basis throughout the study. The retraining and refinement of data collection rules were done as needed if the correlations and percentage of agreements fell below acceptable levels.
Intervention
Patients were randomly assigned to the DM program (DMP) or usual care. After 18 months of the trial, the randomization scheme was changed from a 1:1 to a 1:4 (control/experimental ratio) block scheme, using computer-generated assignment, in order to maintain full caseloads for the intervention team. The 1:4 randomization scheme continued for the remaining 26 months of the study. The DM patients received case management services from an advanced-practice nurse (APN), who had access to a pulmonologist and a geriatrician for guidance and collaboration. The APN met with the patient and family several days prior to hospital discharge in order to review the hospital course, perform a baseline assessment of both the patient and the caregiver, discuss hospital discharge plans, and establish a plan of care. The APN consulted with the hospital care team about the patients care needs and completed a hospital discharge summary that included the post-hospital discharge plan of care for the patient, the patient goals, the presence of advance directives, and an assessment of family coping. This summary was sent on the day of hospital discharge to all of the relevant out-of-hospital health care providers (nursing home staff, family physician, consulting specialist, home care agency, etc).
All of the DMP patients were visited by the APN within 48 h of hospital discharge and a second time within the first week. Visits were made at least weekly for the next 3 weeks and then at least every other week for the last 4 weeks, for a minimum total of eight visits. A visit was also made whenever there was a transition in care location (eg, discharge to home, transfer from one level of care to another, or hospital readmission) to assure continuity in care. The patients who lived > 30 miles from the study site were contacted by telephone rather than through in-person visits. All of the contacts with patient, family, and health care providers were documented using data collection forms.
During the 8-week intervention, the APN performed case management activities, which varied greatly with patient condition, location, and presence of family support. Typical activities included attending team meetings at extended care facilities, helping families prepare for the patients eventual return home, emotional support for family members, counseling families about end-of-life options, coordinating services among multiple providers, arranging for needed follow-up care from specialists, and monitoring patient condition and medications. In addition to participating in overall project management, the geriatrician and pulmonologist were consulted by the APNs as needed for advice regarding medication management, treatment alternatives, and strategies addressing specific patient problems. This collaboration generally took place over the telephone and occurred once or twice a month.
Patients in the usual care group were interviewed within 2 weeks of hospital discharge for completion of study instruments, then at 1 and 2 months post-hospital discharge for data collection. The interviews were conducted in-person at hospital discharge and by telephone after hospital discharge. When patients and family members in the usual care group asked for advice or information from the interviewers, they were referred back to their primary care provider, extended care facility staff, or home care agency.
Instruments
Demographic data (age, gender, and race) were collected on both patients and caregivers, and descriptive clinical data (diagnosis-related group, reason for ventilation, and length of stay) were abstracted from patient medical records. Instruments included the acute physiology and chronic health evaluation (APACHE) III, the Medical Outcomes Study eight-item short form (SF-8), and the outcome and assessment information set (OASIS). Billing data were used to determine the standardized charges for post-hospital discharge use of services, such as nursing home, rehabilitation center, LTAC facility, and hospital readmission.
APACHE III is a well-established severity-of-illness classification tool that measures mortality risk using physiologic and chronic health data taken from the first 24 h of ICU admission. APACHE scores range from 0 to 299, with higher scores representing a higher risk of death.22
The SF-8 is the latest version of the original 36-item instrument designed to measure health status. It consists of eight items, each of which addresses a different dimension of quality of life, and yields two subscale scores (physical and mental). Scores on the physical subscale range from 14.1 to 64.0, with higher scores indicating a better physical health status. Scores on the mental subscale range from 6.8 to 70.4, with higher scores indicting a better mental health status. The SF-8 score was obtained within 2 weeks of hospital discharge and again at 2 months post-hospital discharge. The patients were also asked to complete the SF-8 in reference to their health status for the week prior to hospitalization. Alternative form reliability for summary scores has ranged from 0.85 to 0.90 for the 1-week recall version. For patients with one or more physical comorbidities, the mean (± SD) SF-8 physical scores have been reported as 48.12 ± 9.23, and mean SF-8 mental scores were 54.08 ± 6.54.23
All of the patients, regardless of discharge location, were assessed with the OASIS. The OASIS is a 79-item tool commonly used by home care agencies to assess the care needs and outcome measures of patients.24 Interrater reliability has been reported (Pearsons r, 0.56 to 1.0). The 14 items assessing activities of daily living and instrumental activities of daily living (ADL/IADL) provide a total score ranging from 0 to 66, with higher scores indicating an increased dependency or need for help in performing these activities. Construct validity has been reported25 with functional domain items loaded onto one factor.
The Katzman Short Orientation-Memory Concentration Test was used to determine whether subjects were cognitively impaired prior to conducting the subject interviews. The test includes three orientation questions with the possible points ranging from 0 (normal) to 28. Scores > 6 correlate with dementia.26 Reported reliabilities range from 0.886 to 0.922.27
The resource use was assessed using standardized charges. Standardized charges are a measure for resource use that is both interpretable and standardized across settings and time. We utilized actual billing data from patients rehospitalized during the year 2001 to determine a "standardized charge" for 1 day of rehospitalization. This charge was used to calculate the total charge for each hospital readmission episode during the study period. This method has been used successfully in previous studies2028 by the investigators. We calculated the cost of the intervention by using the total salary of the APNs plus benefit costs.
Statistical Analysis
The comparisons between the experimental and control groups were done using analysis of variance for nonskewed continuous variables, Mann-Whitney U for skewed continuous variables (two-group comparisons), and
2 for categorical variables. Time-to-first hospital readmission was compared using survival analytic techniques, and logistic regression was used to determine variables that predicted hospital readmission, as well as death, following hospital readmission. The sample size was calculated using power analysis that incorporated the following assumptions: level of significance = 0.05, nondirectional hypotheses, medium effect size, and desired power of 90%. Based on these assumptions, a sample size of 256 was needed.29
| Results |
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Most patients, as shown in Table 3 , were discharged from the hospital to an extended care facility, with only 76 patients (22.8%) able to return directly home. Discharge to a nursing home occurred more frequently (n = 122, 36%) than discharges to either an LTAC or rehabilitation facility (n = 68, 20% for both). At the time of hospital discharge, 57 of all patients (17%) still required mechanical ventilation for at least part of the day, and half of the patients (50%) were discharged from the hospital receiving oxygen. Although mean hospital admission APACHE III scores did differ between the groups (Table 2), there were no significant differences in hospital discharge disposition, ADL/IADL scores, or mental health status scores on the SF-8 between the experimental and the control patients. There was a statistically significant difference in the SF-8 physical health score between groups for those patients who were cognitively intact at hospital discharge, with the experimental group having a significantly lower mean.
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Hospital Readmission for Experimental and Control Groups
There was no difference between the experimental and control groups in the relative risk for hospital readmission (see Table 4 ). There also was no statistically significant difference between the groups regarding the percentage of subjects having more than one hospital readmission during the 2-month study period. Although we did not obtain acuity data (APACHE) for hospital readmission, we did examine the primary reason for hospital readmission to see if there were differences between the experimental and control groups. There were no differences between groups on any of the clinical variables for hospital readmission except for "cardiac problems." More than twice as many of the hospital readmissions in the control group (38.9%) were for cardiac reasons (congestive heart failure, chest pain, etc) as compared with the experimental group (15.1%). This difference was statistically significant (
2 = 4.57; 95% CI, 0.16 to 0.92; relative risk, 0.39; p = 0.03).
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Death associated with hospital readmission was less frequent in the experimental group than in the control group (23.7% vs 30.8%, respectively), although the numbers in each group were small, and the difference did not reach statistical significance. There was also no difference in the risk of death following discharge from the readmission hospitalization. The mean number of days from the index hospital discharge date until the date of the first hospital readmission was slightly longer (mean, 15.9 days; 95% CI, 12.8 to 18.9 days) for the experimental group than for the control group (mean duration, 13.9 days; 95% CI, 9.4 to 18.5 days; p = 0.64). We also compared patients who were followed in-person (lived
30 miles from study site) with those who were followed long-distance by phone (lived > 30 miles from study site) to see if there were any differences in outcomes. We found no statistically significant differences between the groups for any of the hospital readmission variables.
The reason for hospital readmission was available from the medical records of those patients (n = 72) who were readmitted to the primary study hospital. Hospital readmissions were classified by research nurses as related to worsening of the original primary disease diagnosis (18%), worsening secondary diagnosis (29%), and/or development of a new problem (60%; 15 patients had two reasons for hospital readmission). There were no differences between the experimental and the control groups, tested with Fisher exact test. The most common clinical problem prompting hospital readmission was infection, and the most common type of infection was urinary tract.
Predictors of Hospital Readmission
Using logistic regression, we examined the influence of variables shown to predict hospital readmission in other studies1419303132 within the first 2 months of index hospitalization. Variables included as covariates were the following: age, gender, length of mechanical ventilation, functional status at hospital discharge (ADL/IADL scores from the OASIS), hospital admission APACHE III score, renal dialysis, presence of diabetes, and pressure ulcer at hospital discharge. The model with all of the variables in the equation was statistically significant in predicting the hospital readmission (p = 0.024) and the correct classification for hospital readmission, and no hospital readmission within 2 months of index hospital discharge occurred 62.3% of the time (R2 = 0.074 [Nagelkerke test]). Only one of the variables made a statistically significant contribution to the prediction of hospital readmission: functional status at hospital discharge (odds ratio, 1.13; 95% CI, 1.029 to 1.248; p = 0.011).
Next, we added the intervention variable to evaluate the impact of the intervention on hospital readmission. Adding the intervention variable to the model did not significantly increase the correct classification of hospital readmission. With the intervention variable in the model, correct classification for hospital readmission and no hospital readmission within 2 months of index hospital discharge occurred 65.2% of the time, an increase of only 2.9% over the model without the intervention variable included.
Hospital Readmission and Health Status
Using data from patient sources (no proxy data were included), we examined the physical and mental aspects of health status at hospital discharge of patients who were readmitted to the hospital. The physical SF-8 subscale variable was positively skewed, and the nonparametric Kruskal-Wallis test was used. As would be expected, patients residing at home prior to their first hospital readmission had higher (better) physical health scores than patients residing in all of the other types of facilities (p = 0.001). The mental SF-8 subscale variable was not highly skewed, and analysis of variance was used to compare mean mental health scores. Mental subscale scores behaved similarly to the physical scores, and those differences were also statistically significant (p = 0.002).
We then examined the physical and mental SF-8 subscale scores to determine whether there were differences between those patients readmitted to the hospital and those who were not readmitted. There were no statistically significant differences in the physical scores between those readmitted to the hospital (mean, 28.7; 95% CI, 27.2 to 30.3) and those not readmitted (mean, 30.4; 95% CI, 29.1 to 31.7; p = 0.116), nor in the mental subscale scores between those readmitted to the hospital (mean, 37.6; 95% CI, 35.3 to 39.9) and those not readmitted (mean, 38.1; 95% CI, 36.2 to 39.9; p = 0.766).
Cost Effectiveness
To examine the cost-effectiveness of reducing the hospital days for hospital readmissions, we calculated the total savings from 6.31 fewer days of hospitalization (for patients in the experimental group) minus the cost of the APNs who provided DM services. The salary plus benefit costs (fiscal year 2001, the same year used to obtain charges for services used) for two full-time APNs for 2.8 years (the duration of the intervention) was $420,000. Given the reduction in hospital days for the experimental group of 6.31 days per patient, at an average hospital charge of $3,415/d, the average savings were $21,548.65 per patient. Assuming that this savings was realized for each of the 93 rehospitalized intervention patients, the total reduction in hospital charges was estimated at $2,004,024. Approximating costs by using the study hospitals Medicare cost-to-charge ratio of 0.45, rehospitalization cost savings were estimated at $901,810. Thus, after accounting for the salary costs of the APNs, the total savings were $481,811 for the 93 subjects who were readmitted or $5,180 per patient.
| Discussion |
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Our results suggest that, first, patients who have survived a prolonged stay in an ICU are another group who are at high risk for hospital readmission, particularly within the first 2 months following hospital discharge. This finding is consistent with our previous investigations of this patient population.14 Second, although the frequency of hospital readmission was not altered by the intervention, some aspects of the hospital readmission pattern were modified by DM services. Third, because the number of costly rehospitalization days was significantly reduced, the provision of DM services was cost-effective.
DM programs have gained popularity as they have demonstrated the ability to improve outcomes and lower costs of common chronic conditions.4647 The three diseases most likely to be managed through DM programs are asthma, diabetes, and heart failure, and it has been estimated that as many as 25% of enrollees in managed-care insurance plans have access to DM programs.48 Although there has been some recognition that single-condition DM programs may be inadequate in improving care for the many people with multiple chronic conditions,49 there have been no other reports of applying DM principles to patients with multiple comorbidities, such as the CCI.
There are several possible ways in which the DM program we implemented may have led to the reduction in the duration of rehospitalizations and, possibly, in deaths associated with rehospitalization. Clarification of goals of care, resulting from the intensive support and counseling of patients and families in the period between initial hospital discharge and hospital readmission, was able to make the eventual transition from the readmission hospitalization back to an extended care facility more efficient. It is also likely that the improved communication and transmission of information between facilities and care teams accomplished by the APNs increased the efficiency of assessment, care planning and delivery during the rehospitalization. It may also have been that the close monitoring provided by the APNs was associated with more timely recognition of the need for rehospitalization, facilitating earlier intervention and, thus, a shorter hospitalization. However, the fact that the mean number of days between index hospital discharge and hospital readmission was slightly longer for the experimental group than control argues against this explanation.
Relatively simple, low-cost improvements in communication and coordination, recognized components of all DM programs,50 can have significant effects on care processes. By the time of hospital discharge, CCI patients have undergone multiple procedures, had exacerbations of many preexiting conditions, and have experienced repeated episodes of complications, such as sepsis and renal failure. Management of these complex patients is difficult when information is lacking or when it is available only after hours of sorting through volumes of medical records. In our study, providing a written summary of the lengthy and complicated illness course of the patient to each team of providers was almost universally identified as a significant help to the receiving care team. This is consistent with the work of van Walraven and Rokosh51 and van Walraven et al,52 who found a trend toward the reduced risk of hospital readmission among patients seen in follow-up by a physician who had received a written hospital discharge summary.
Finally, the ineffectiveness of the intervention in reducing hospital readmission rate and the predominance of a new problem as the reason for hospital readmission suggest that the hospital readmission rate is primarily a function of the natural pattern of chronic critical illness. As has been found in many other chronic conditions, prehospital functional status was the strongest predictor of rehospitalization.184042 This suggests that hospital readmission rate is a relatively insensitive outcome measure, although the frequency of urinary tract infection as a reason for hospital readmission might warrant targeting urinary tract infection prevention in post-hospital discharge quality improvement programs. In contrast, the length of stay for the hospital readmission, although in part a function of the condition that led to the hospital readmission, is apparently able to be shortened by the provision of the care coordination aspects of DM services. Additional trials of interventions should be tailored less toward reducing the hospital readmission rate and more toward preparing for and managing hospital readmissions efficiently, thus minimizing the human and financial costs.
Strengths and Limitations
The strength of our study was that it was a randomized trial and enrolled all of the eligible patients, regardless of their primary disease diagnosis or hospital discharge location. The intervention was implemented by experienced, skilled practitioners, but did not require any specialized training, nor did it require changes in the normal work schedule or pattern of the physician team members. As such, the results are applicable to the heterogeneous population of patients who become CCI and the clinicians who care for them.
Although the choice of 72 h of ventilation was intentionally liberal, in order to assure inclusion of all patients likely to experience prolonged ventilation, it probably did result in a sample that also included patients who did not share some of the more typical features of chronic critical illness. For example, relatively young patients with few comorbidities who require 3 or 4 days of ventilation either as part of treatment for a serious community-acquired pneumonia or severe asthma exacerbation can recover with few sequelae and relatively few post-hospital discharge care needs. The inclusion of patients like this who were at low risk for hospital readmission likely reduced the effect size of the intervention. More stringent enrollment criteria might have allowed a more sensitive analysis.
The study was limited in both the precision and comprehensiveness of measures of cost. Our results are also limited in generalizability in that the sample was drawn from one academic medical center, and the costs were calculated from charges in that facility. These rates are likely to be higher than in smaller community facilities. Given the high cost of care for patients with prolonged critical illness, a closer examination of all costs of care, including extended care facility costs, home care, and physician visits, is warranted.
Although we did not identify any demographic or clinical differences between the subjects who consented and those who refused, the high-refusal rate (28.5%) may be a threat to validity. However, because a majority of the refusals to participate were made by caregivers of patients too ill to consent who stated that they felt too overwhelmed to participate in research, it seems probable that those patients and caregivers most likely to benefit from a supportive intervention, such as the DMP, did not participate. Thus, the refusal rate, while of concern, may have resulted in underestimating, rather than overestimating, the effect of the intervention.
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| Footnotes |
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This study was supported by a grant from the National Institute of Nursing Research (NR-05207).
Received for publication October 10, 2004. Accepted for publication January 28, 2005.
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