Hospitalizations can be frequent, costly, and signal a poor prognosis for patients with heart failure (HF). In Canada, HF is the most common reason for hospital admissions in patients older than 80 years and the third most common reason for admission for patients 60 to 79 years of age.1 In Alberta, Canada, where this study was undertaken, 18% of HF patients hospitalized between 2004 and 2008 experienced unplanned readmission within 30 days, one-third of which occurred within the first 7 days.2
Readmission to hospital within 7 days after discharge may more closely reflect inadequacies associated with the initial hospital stay than the more commonly used outcome measure of readmission within 30 days after discharge.3–6 Yet, few researchers focus on this 7-day outcome. Instead, the focus is on readmission within 30 days of discharge, a time when many patient and community-based factors, over which hospitals have little control, can affect a patient’s health and may not be modifiable.5
Unplanned readmission within 7 days after discharge has been identified as highly avoidable, yet little is known about factors influencing these events. A recent study shows that factors associated with increased likelihood of all-cause 7-day readmissions include history of kidney disease, transfer to index hospital, discharged with homecare services, and discharged against medical advice.2 Other studies reported that factors associated with 7-day readmissions include patient characteristics such as age, sex, marital status, comorbid conditions, reason for index (first) admission, and clinical status near discharge.7,8
Frailty is a patient characteristic that may be a valuable maker of severity and potential factor influencing 7-day readmissions. Patients admitted for HF older than 75 years exhibited a significantly greater likelihood of 30-day readmission.2 Frailty is interrelated with comorbidity and disability and is evidenced by dependency on others for activities of daily living.9 This is especially true for elderly patients when afflicted with HF that can affect strength, gait, endurance, and cognition. Heart failure combined with other comorbid conditions increases the risk of readmission and frailty.10,11 As these studies suggest, age, comorbidity, and disability are contributors to frailty. Although younger patients may be considered frail, we defined frailty as patients who were older than 75 years, have more than 3 comorbid conditions, and required assistance with activities of daily living (eg, used a walker or cane, depended on other people for meals or personal care). As well, processes of care, such as medication use, diagnostic tests, patient education, referral to specialty services, and posthospitalization follow-up, which may also influence patient stability and risk for readmission, have not been well studied.
Thus, the purpose of this study is to examine factors that influence 7-day readmissions after discharge for HF. Using a matched pair case-control design, we conducted a comprehensive health record audit to examine the sociodemographic, clinical, and processes of care factors associated with risk of all-cause readmissions within 7 days after hospital discharge. We hypothesized that patients who are readmitted within 7 days of discharge have particular characteristics that may predict their readmission.
Alberta administrative inpatient discharge data were used to identify all first occurring (index) hospital discharges with the most responsible diagnosis field coded I50.x of the International Classification of Diseases, Tenth Revision between April 1, 2002, and March 31, 2012.2 To maximize identification of only first occurring HF hospitalizations, we excluded all patients with discharges for HF between April 1, 2002, and March 31, 2004, known as a washout period. Patients were included if discharged alive from any of the 3 acute care hospitals in Calgary, Alberta, between April 1, 2004, and March 31, 2012.2 These hospitals offer inpatient and outpatient cardiovascular and HF services, with a high volume of HF patients annually. We excluded discharges meeting any of the following criteria: (1) not an Alberta resident or service not provided in Alberta facility, (2) age younger than 19 years or older than 105 years, (3) in-hospital death, and (4) discharged to another acute care facility. However, if repeated separations occurred and were followed by readmission within 7 days, the records were included to capture the maximum number of readmissions occurring within 7 days of discharge. From the remaining patients not readmitted within 7 days after discharge, 1:1 controls were matched by sex, by 5-year categories of age (eg, 60–64 years), and by discharge date within the same fiscal year (Figure).
The Conjoint Health Research Ethics Board and Alberta Health Services approved this study.
Chart data were collected from hybrid electronic- and paper-based health records. Each item on the data collection form included a definition of the variable and location in the health record. Two research assistants underwent extensive training with the investigator regarding data definitions. Interrater reliability was established using 20 health records across the 3 sites (κ near perfect: mean, 0.88; range, 0.6–1.0).
Study Variables in Index Health Records
Chart data sources included the emergency department admission forms, history and physical documents, interdisciplinary progress notes, laboratory and diagnostic reports, and discharge summaries. Data for some physiologic variables (eg, weight, comorbid conditions, type of HF, blood pressure, serum creatinine, and congestion on chest x-ray) were collected to determine the patient’s status at the time of index admission and index discharge.
Clinical instability, especially within the last 48 hours prior to discharge, has been identified as a predictor of death or readmission.12,13 Medical or nursing documentation of signs and symptoms of congestion within 48 hours before discharge was identified to determine the patient’s clinical status.
Frailty (defined as >75 years of age, >3 comorbid conditions, and required assistance with activities of daily living) was used to account for disease severity. All 3 components were required to classify patients as frail.
Variables related to processes of care were among those recommended in clinical practice guidelines for HF.14–16 Examples include documentation of HF-specific patient education, evaluation of left ventricular function, referrals to specialty services, and specific medications prescribed at discharge. We included goal of care level (ie, the amount of medical care with or without resuscitation or intensive care admission), end-of-life discussions (eg, discussion of prognosis, or shifting to symptom management versus aggressive intervention), and instructions for follow-up with an outpatient physician in general and within 1 week of discharge.
Study Variables in Readmission Health Records
Variables in the readmission health records focused on clinical status at the time of readmission. We identified vital signs, documentation regarding visits to a clinic or emergency department between hospitalizations, signs of dehydration, and signs or symptoms of congestion (eg, lung crackles, leg edema, dyspnea). If the readmission was for HF, the acute HF type was determined.17
Sociodemographic, clinical, and health services variables of the index admissions for both readmitted and nonreadmitted groups were characterized using descriptive statistics. We used Student t tests for continuous variables and χ2 tests for dichotomous variables to compare the characteristics of patients who were readmitted and not readmitted. We computed the statistical significance of the difference between the paired cases and controls (P values) using paired t tests for continuous variables and McNemar χ2 tests for categorical variables (P < .05). Univariate logistic regression was used to identify crude associations with readmission for each independent variable. Finally, variables were selected for inclusion in conditional multiple logistic regression models based on their significance in univariate analysis or their clinical importance. Given the matched-pair study design, all models implicitly adjusted for age, sex, and fiscal year of discharge.
Of 18 590 patients admitted between April 1, 2004, and March 31, 2012, with a most responsible diagnosis of HF, 234 patients were readmitted to hospital within 7 days after discharge and 191 matched pairs were analyzed (Figure).
Readmitted patients were more likely to have a cardiologist or other specialist as their attending physician during the index admission, be frail, have pulmonary edema or pleural effusion on the first chest x-ray, and did not lose weight (fluid) during the index admission (Table 1). At the time of index hospital discharge, readmitted patients were more often referred to an HF clinic or cardiologist upon index discharge and had documentation of end-of-life discussions in the health record (Table 2). A note to follow-up with a family practice physician within 1 week of discharge was found less often in records of patients who were readmitted than those not readmitted.
Multivariate logistic regression modeling with forward stepwise addition of the significant variables found in the univariate analysis revealed that frailty and having a specialist as attending physician remained significantly associated with increased likelihood of readmission. Documented instructions to follow up with a family practice physician within 1 week of discharge remained significantly associated with reduced likelihood of readmission (Table 3).
Of the readmitted patients, 54% (103) of the patients presented with cardiac symptoms, 77% (79 patients) of these patients with HF; most classified as warm and wet acute HF (Table 4). There was a high frequency of signs and symptoms of congestion in the readmitted patients, although HF was not always the primary diagnosis. Twenty-eight of the readmitted patients (14.7%) died during the rehospitalization.
Despite readmission within 7 days of discharge, 35% of patients were not referred to any support services at their second discharge. One-third of the readmitted patients were referred to a heart function clinic or cardiologist after discharge. Seventy-one of the 191 readmitted patients’ records included HF-specific patient education documentation. The goal of care was documented at the same frequency (78%) in the index and readmission records. End-of-life discussions were documented slightly (23.6%) more often in the readmission health records than in the index health records (16.2%) of the not-readmitted cohort. Comparing disposition of the index admission and readmission, after readmission, fewer patients went home without support or with homecare services, and more patients were transferred to continuing care facilities. Slightly more patients (2.1%) were discharged with palliative or hospice services than during the index admission.
Discussion and Clinical Implications
Risk Factors For Readmission
We determined risk factors associated with readmission within 7 days of discharge using health record data. Frailty and attending physician as specialist during the index admission were significantly associated with increased likelihood of readmission. The only variable associated with a reduced likelihood of readmission was documented instructions for the patient to follow up with a family physician within 1 week of discharge.
Patients identified as frail were twice as likely to be readmitted within 7 days of discharge, even after accounting for index admission physician type, weight change during index admission, and outpatient follow-up patterns. Frailty may predispose cardiovascular patients to a lower threshold for HF decompensation or the HF alone may trigger the physiologic changes of frailty that increase the risk readmission in HF patients.18 Although it is not clear which comes first, evidence is building that frailty significantly contributes to poorer quality of life, morbidity, and mortality in patients with HF.18–22 Given that frailty is considered a manageable condition like HF,23 fewer readmissions may occur with screening and early intervention for both syndromes.
Although more detailed validated frailty measures exist, using simple 3-point criteria for identifying frailty had a major advantage. The data were readily identifiable in health records. There are more than 20 tools available for frailty screening.18 Criteria that require no questionnaires or physiologic testing are more practical for screening for frailty in acute care settings and may be more readily adopted into nursing admission intake processes. The rates of frailty in this study were similar to rates reported in other studies of HF patients.9,24 Specifically, 35% of the HF patients in our sample were frail, which aligns with 21% to 48% frailty rates in cardiovascular populations when more complex definitions of frailty were used.9,24 The 3 criteria included in this definition of frailty were useful and warrant further testing (ie, age >75 years, >3 comorbid conditions, requiring assistance with activities of daily living).
Patients under the inpatient care of a specialist (ie, cardiologist, internist, or other specialist) during the index admission had a greater likelihood of readmission within 7 days of discharge even after accounting for the 5 other variables in the multivariate models (ie, frailty, note to see physician within 1 week after discharge, end-of-life discussion documented, referral to HF clinic or cardiologist, and no weight loss during index hospital admission). Other studies have found no association between specialist or cardiologist care and 30- or 60-day readmission after HF hospitalization.2,7,25 One might expect specialists to provide more thorough treatment resulting in fewer readmissions. Alternatively, a greater number of readmissions may represent more intensive monitoring and more aggressive treatment by a specialist. We adjusted for disease severity by including frailty in the regression models, which could account for the differences seen in this study. The inclusion of more clinical variables might have accounted for HF disease-specific severity, but variables, like ejection fraction, were not consistently reported. Blood pressure upon index admission and discharge and readmission were captured but, after sensitivity analysis at various cut points, showed no difference between groups.
Documentation of instructions to follow-up with a physician within 7 days of discharge occurred in 59% of the sample and was strongly associated with reduced likelihood of readmission within 7 days. This factor is a novel factor, although previous reports, such as Bradley et al,26 indicated that arranging follow-up visits before discharge was associated with reduced 30-day readmissions after HF hospitalization. Hernandez et al3 reported lower 30-day readmission rates in hospitals with the highest level of follow-up appointments with any physician within 7 days of discharge after HF hospitalization, suggesting that fewer admissions occur irrespective of the manner in which follow-up interventions occurred. No study to date has shown superiority of any one method. We identified instructions for follow-up on patients’ charts that showed the greatest association with reduced risk of readmission.
In this study, HF was the presenting diagnosis for 41% of patients readmitted within 7 days after discharge, reinforcing the importance of optimal treatment of congestion prior to discharge.
In contrast to studies measuring 30- and 60-day outcomes, very early readmission in this cohort was not associated with other physiologic factors such as blood pressure,27 atrial fibrillation, history of myocardial infarction,28 or history of renal failure.2,29,30 Eastwood et al2 reported that a history of renal disease increased the likelihood of all-cause readmission within 7 as well as 30 days after discharge. After closer examination of the same sample for this study, patients did not often present to hospital with overt renal failure (eg, elevated creatinine) but rather reinforces the complex nature of the cardiorenal syndrome.
Strengths and Limitations
Patients from 3 different tertiary care hospitals that serve diverse urban and surrounding rural populations were included in this study. We captured only patients readmitted to Calgary hospitals. We acknowledge the potential for bias in that patients admitted in Calgary but readmitted to a hospital outside the area may have some different characteristics.
The detailed health record reviews at each hospital enabled validation of diagnoses and examination of clinical details versus analyzing only admitting or discharge diagnoses. Although using health record data can pose challenges largely because of the potential for missing data, we examined health records of large numbers of study subjects enhancing the statistical power and generalizability of the findings.
A limitation with any health record audit is that the quality of health record data is dependent upon the quality of documentation. Our data were limited to what was documented and may not fully represent actual practice or include information related to readmission, such as social support and medication compliance at home.
The outcome of interest in this study was nonelective all-cause readmission within 7 days of discharge. We did not track or report patients who died within the first week after discharge. The postdischarge mortality rate within 7 days of discharge is low and would not have had a large impact on the results. We studied readmission only and while deaths are important, inclusion of deaths would serve a different research question. We consider readmission so near to discharge to closely reflect the clinical status at discharge and the interventions at or near the time of transition to the community.
Our frailty criteria were based on information readily available in health records and produced an estimate of frailty within the range of other HF populations.18,22 The criteria used in this study have not been prospectively validated.
Implications for Practice
These results reveal the value of examining 7-day readmissions, the need for nurses to screen HF patients for frailty, and the need to schedule patients for immediate follow-up after discharge. Studying 7-day readmissions enabled focused attention on clinical status of the patient when discharged and the transitional care processes, with fewer confounding factors like quality of outpatient care. Nurses, as part of multidisciplinary teams, can activate improvements to inpatient and transitional care processes, to address these potentially avoidable readmissions. Specifically, these results point to the need for nurses to screen for frail patients who are vulnerable to readmission. Although requiring validation, nurses could use the suggested 3-point criteria for frailty as part of routine admission assessment. As well, nurses can ensure consistent scheduling of follow-up appointments within 7 days of discharge. This practice is a simple intervention that was found to be highly associated with a lower risk of readmission within 7 days of discharge. Scheduling an early follow-up visit within 7 days after discharge is recommended in HF clinical practice guidelines and as a performance measure.31,32 Closer follow-up may be required for more effective prevention of readmissions.
We report easily obtainable factors, including indicators of frailty, attending physician type, and patient instructions for follow-up post discharge that may be used to assist in identification of HF patients at increased risk of early hospital readmission. Further research of early hospital readmission for patients with HF, including efforts to prospectively validate our findings, is suggested.
What’s New and Important
- Studying 7-day readmissions enabled focused attention on clinical status of HF patients when discharged and the transitional care processes, with fewer confounding factors, like quality of outpatient care.
- Heart failure patients at risk of 7-day readmission were more likely to be frail.
- Heart failure patients who were instructed to follow up with a physician within 7 days of discharge had reduced risk of 7-day readmission.
- Future research is needed to validate readily identified clinical factors that define frailty.
Thanks to Bing Li, Guanmin Chen, Melody Lough, and Brooke Forrest for their valuable assistance with this study.
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Keywords:Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved
case-control studies; frail elderly; heart failure; hospital readmission