Comparison of 30-day planned and unplanned readmissions to huge hospital in China

Abstract

Purpose: To compare and analyze the clinical characteristics and influencing factors of planned and unplanned readmissions within 30 days to provide a basis for the quality of care management.

Methods: We searched for inpatients at West China Hospital from January 1, 2015, to December 31, 2020. Patients were divided into unplanned readmission and planned readmission groups according to 30-day readmission status. Patient demographics and related information were collected for each patient.

Results: We identified 1,242,496 hospitalized patients, including 74,494 (6.0%) 30-day planned readmissions and 9,895 (0.8%) unplanned readmissions. There were statistically significant differences between planned and unplanned readmissions in terms of patient gender, marital status, age, length of initial stay, the time between discharge, stay in ICU, surgery, and health insurance.

Conclusion: Accurate information on 30-day planned and unplanned readmissions facilitates effective planning of healthcare resource allocation. Identify risk factors for 30-day unplanned readmission and develop interventions to reduce readmission rates.

Introduction

Hospital readmission is a serious, common, and costly adverse patient outcome. Unplanned readmission is not only an indicator of the critical quality of care for patients but also a significant factor in rising healthcare costs [1, 2]. Readmissions account for billions of dollars in annual Medicare expenditures [3]. There is growing recognition that readmission is an outcome measure of the metric quality of healthcare, cost reduction, and transitions of care [4].

The unplanned readmission within 30-days after discharge is an important indicator of the cost and quality of health care service and is strongly related to clinical and sociodemographic characteristics [5, 6]. Reducing readmission is the primary task for hospitals and clinicians to improve the quality of healthcare and reduce costs. To address readmissions, the Centers for Medicare and Medicaid Services developed the Hospital Readmissions Reduction Program (HRRP) in 2010 and implemented it in 2012 [7, 8]. Its purpose is to encourage hospitals to improve the quality and transition of healthcare to a better plan of discharge, thereby effectively reducing avoidable 30-day readmissions [8]. The first important step in reducing readmissions is to determine the incidence, risk factors, and causes for readmission. This information can help identify patients at high risk of readmission and implement specific interventions to reduce avoidable readmissions.

Research on the relationship between healthcare quality and readmission needs to distinguish between planned and unplanned readmission, as only unplanned readmission can reflect the healthcare quality at the first hospitalization. Planned readmissions may be associated with the utilization of hospital resources (multiple admissions for reimbursement purposes or therapeutic procedures), but not with the healthcare quality process [9]. Although a large number of readmission studies have been conducted, however, it is unclear whether planned and unplanned 30-day readmissions differ across hospitals. The reasons for unplanned readmissions have also not been fully elucidated. The relative contribution of patient-level risk factors to structural hospital characteristics in terms of variation in unplanned readmissions is not fully understood. As the OECD reports, identifying those truly unplanned readmissions is complex [10].

The aim of this study was to describe the incidence of planned and unplanned 30-day readmissions and to investigate the incidence in relation to time. We sought to analyze the characteristics of readmitted patients and to identify risk factors associated with unplanned readmission. This will provide a basis for improving healthcare quality and optimizing the discharge process.

Method

Results

Among 1242496 hospitalized patients between January 2015 and December 2020, 84389 cases were readmitted within 30 days from the patient’s discharge from the hospital. It included 74,494 planned readmission and 9,895 unplanned patients. There were significantly more women with planned readmissions versus unplanned readmissions at 67.0% and 51.3%, respectively. The age groups with the largest number of planned and unplanned readmissions were 40≤-＜49 (21,653 cases, 29.1%) and 50≤ -＜59 years (2,074 cases, 21.0%), respectively. The number of days of initial hospitalization for patients with planned and unplanned readmissions was predominantly in the 1≤-＜4 day group, 67.0% (49,936 cases) and 46.5%(4,600 cases), respectively (Table 1). The age group with the lowest number of patients with planned and unplanned readmission was both ≥80 years old (0.9% vs 4.2%). Table 1 shows the demographic data and associated risk factors for planned and unplanned patient admissions.

Table 1 Characteristics of patients’ readmissions.  

Comparison of disease with planned and unplanned readmission

The disease with the highest number of planned readmissions was encounter for antineoplastic chemotherapy (62,756, 35.3%), followed by radiotherapy sessions for malignancy (919, 11.2%) and systemic lupus erythematosus (607, 13.1%). The disease with the highest number of unplanned readmissions was encounter for antineoplastic chemotherapy (2038, 1.1%), followed by age-related cataract (1,061, 5.0%) and unspecified disorder of refraction (544, 10.6%) (Table 2).

Table 2 Readmissions numbers and rates in Disease

Comparison of departments with planned and unplanned readmission

Planned readmissions were most frequent in the department of head and neck oncology both in terms of the total number (38461) and readmission rates (45.0%) followed by the department of hematology (9851, 29.9%). The highest number of unplanned readmissions was in the department of head and neck oncology (1172, 1.4%), followed by the department of nephrology (595, 1.5%) and hematology (547, 1.7%). The highest unplanned readmission rate was in the department of rheumatology (2.2%), followed by the department of ophthalmology (2.1%) and hematology (1.7%). The number and rate of planned and unplanned discharges in the department of internal medicine were much higher than the number and rate of planned and unplanned admissions in the department of surgery (Table 3).

Table 3. Hospital sections’ characteristics

Annual distribution of planned and unplanned readmission

The number of planned readmissions and planned readmission rates increased incrementally with the number of inpatients except in 2020. The number of planned readmissions and readmission rate (15996, 6.7%) was the highest in 2019. The number and readmission rate of unplanned readmissions (2451, 1.2%) was highest in 2020 (Table 4). 

Table 4 Chronological distribution of planned and unplanned readmission

Monthly distribution of planned and unplanned readmission

Among the 12 months of the year, the highest number of patients planned readmission was in November (7,283, 9.8%), followed by September (7,201, 9.7%) and July (7,108, 9.5%). The highest number of unplanned admissions was in September (1,020, 10.3%), followed by November (1,008, 10.2%) and December (984, 9.9%). The month with the lowest number of planned and unplanned admissions was February (4,372, 6.6% vs. 437, 4.9%) (Table 5).

Table 5 Monthly distribution of planned and unplanned readmissions

Discussion

In this study, we analyzed planned and unplanned 30-day readmission rates and related characteristics at a large general university hospital in China. It is the only hospital in the region with the highest referral rate among all medical specialties and it treats the most complex and difficult cases, which are more likely to be readmitted.

We found some significant differences between 30-day planned and unplanned readmission patients. According to our study, women are twice as likely as men to plan readmission. However, there were 2.5 percentage points more female patients than male patients in unplanned readmission. There were significantly more female patients with planned readmission than those with unplanned readmission (P<0.001). Some studies recognized men as a risk factor for 30-day readmission [10]. However, most studies that included sex-based readmission showed no difference between sex and readmission rate [11,12]. Although gender may be a risk factor for readmission in some diseases [11], large prospective studies of gender-based readmission are needed.

The proportion of patients who lived with a spouse was significantly higher in planned readmissions than in unplanned readmissions, and the proportions of divorced, single, and widowed were significantly higher in unplanned readmissions than in planned readmissions (p<0.001). This result is consistent with previous studies showing that marriage has a protective effect on unplanned readmission [13-15]. 

In this study, the interval from discharge to readmission was mainly concentrated in 20≤-≤30 days for both planned and unplanned readmission patients, 55.9% and 45.7%, respectively, the interval between planned readmission was significantly higher than that of unplanned readmission (17.05±8.96 days vs 16.79± 10.02). The results of this study showed that 5683 patients (7.6%) had planned readmission within 7 days (1≤-＜7), of which 1262 (1.7%) were readmitted within 3 days (1 ≤-＜3). From a clinical perspective, this may be a misclassification of planned readmissions. This requires additional validation work (review of the medical record) to explore in more detail planned readmissions that may have been misclassified [16]. Most studies suggested that a 7-day cut-off is an effective intervention point for early readmission and preventable ones [16]. The readmissions within the first seven days following hospital discharge were more likely to be preventable than those occurring within a late period of 8–30 days [16-18]. Some studies have shown that early readmissions (≦7 days) within 30 days of discharge are twice as likely to be preventable compared to late readmissions, with adjusted preventability rates decreasing significantly after day 7 post-discharge. Readmissions within one week of discharge were more likely to be preventable [18-20]. Other studies considered readmissions that occurred within 0 to 10 days were judged to be avoidable [21].

In the present study, oncology patients had the highest number of chemotherapy in both planned readmissions and unplanned readmissions. This is related to the highest number of oncology patients hospitalized in this study. The number and proportion of planned readmissions in the department of internal medicine greatly exceeded those in the department of surgery. With the exception of ophthalmology, the number and proportion of unplanned readmissions were much higher in the department of internal medicine than in the department of surgery. Planned readmissions patients were primarily related to the specific nature of a disease, which is considered unavoidable because they result from a typical clinical pathway [22]. However, insight into planned readmissions can facilitate efficient allocation and optimization of healthcare resources.

Based on this study’s findings, there was a correlation between planned readmissions of patients, with the number of hospital inpatients increasing each year from 2015 to 2019, as did the number of planned readmissions. Decrease in both inpatient admissions and planned readmissions in 2020 due to the COVID-19 pandemic. However, we did not find a correlation between the number of unplanned readmissions and hospitalizations. Especially in 2020, although the number of hospitalizations was lower than in 2017 the number and proportion of unplanned readmissions were the highest. This may be related to COVID-19 affecting the health status of patients or affecting the quality of care. This reason needs to be further studied.

Throughout the year, planned and unplanned readmission showed a month distribution over the last 6 years. The highest number and rate of planned and unplanned readmissions were in November (7283, 9.8%) and September (1020, 10.3%), respectively. However, the number and rate of planned and unplanned readmissions were the lowest in February (4372, 5.9% vs 435, 4.4%). February is usually the Chinese Lunar New Year, and due to traditional Chinese culture, hospital visits are not usually made during the New Year [23]. The factor is often specific to the Asia countries’ context, reflecting the social and cultural. Therefore, we consider that social and cultural factors are also the influencing factors of planned and unplanned readmission.

Limitation 

This study has several limitations. First, the study used data from one university hospital, and our results are possibly valid only for similar providers, thus, generalizing these findings to other types of hospitals may be risky. Second, the study is retrospective and included a limited number of variables, and therefore is subject to residual confounding and may differ from the true causal effect. Third, we validated the ICD-10 codes, there may be inaccuracies in coding that may introduce imprecision in our estimates. 

Conclusions

Planned readmissions may be misclassified. The study of planned readmissions can help optimize and allocate health care resources. The analysis of unplanned readmissions will help identify key combinations of interventions that are effective in preventing readmissions.

Abbreviations

HRRP: Hospital Readmissions Reduction Program

EHR：Electronic Health Record 

ICD-10: International Classification of Diseases, 10th Revision

Declarations

Author contributions

Jialin Liu, and Mengjiao Zhang conceived the study. Jialin Liu, Mengjiao Zhang，Siru Liu and Yongdong Bi performed the analysis, interpreted the results and drafted the manuscript. All authors revised the manuscript. All authors read and approved the final manuscript.

Acknowledgements

N/A

Funding

N/A

Availability of data and materials

Data cannot be shared publicly because of West China hospital regulations. Data are available from the Bioethics Committee at West China hospital, Sichuan University

(contact via 86-28-85422654) for researchers who meet the criteria for access to

confidential data.

Ethics approval and consent to participate

The study was approved by the Bioethics Committee at West China hospital Sichuan

University (2022-174). Only information that was routinely collected during hospitalization was used. We used anonymous electronic medical records, so we did not seek written consent from patients. A statement to confirm that all methods were carried out in accordance with relevant guidelines and regulations

Consent for publication

N/A

Competing interests

The authors declare that they have no competing interests.

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