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Introduction

Unplanned readmissions, as a critical indicator of healthcare quality and safety, not only significantly increase the financial burdens on patients but also lead to the waste of societal healthcare resources.¹ Internationally, unplanned readmission rates have been incorporated into healthcare quality evaluation systems and are regarded as an important adverse indicator. Quality improvement tools are increasingly being applied to enhance healthcare quality, helping hospitals identify and address service issues, thereby optimizing management and improving patient satisfaction and healthcare quality.^2,3 Within China’s healthcare context, intensified market competition among hospitals has further exacerbated the risk of unplanned readmissions for patients.⁴ Existing research on unplanned readmissions has primarily focused on department- or disease-specific analyses, yet it lacks a systematic hospital management perspective. This study aims to use fishbone diagram and Pareto chart analyze the root causes and primary influencing factors of unplanned readmissions and to develop targeted management strategies, providing a theoretical basis for reducing unplanned readmission rates.

Materials and Methods

Study Design and Setting

This retrospective study was conducted at a public tertiary general hospital in Chengdu, Sichuan Province, China, covering the period from January 1, 2023, to December 31, 2024. The study protocol was approved by the hospital’s ethics committee.

Participants

Inclusion criteria required patients to meet all three conditions: 1) the interval between two hospitalizations was within 31 days; 2) the readmission was unplanned; 3) the readmission was due to the same disease or surgical complications. Patients of all ages were eligible. Each qualifying 31-day unplanned readmission event due to the same disease or surgical complications was analyzed as an independent observation, including recurrent events per patient. Exclusion criteria included patients who left against medical advice and those admitted for chemotherapy, radiotherapy, or other medical care for malignant tumors.

Definition of Unplanned Readmission Rate

The definition of “unplanned readmission rate” was based on the National Tertiary Public Hospital Performance Assessment Manual (2024 Edition) in China. It is defined as the proportion of patients readmitted within 31 days after discharge due to the same or related diseases, excluding planned readmissions.⁵ Numerator: Number of readmissions within 31 days due to the same or related diseases. Specifically, “same disease” refers to readmission with the same primary diagnosis ICD code category and subcategory; “related diseases” refers to readmissions due to surgical complications. Denominator: Total number of discharges during the same period, excluding patients who died, left against medical advice, or were admitted for chemotherapy, radiotherapy, or other medical care for malignant tumors.

Data Collection and Analysis

Medical records for admissions from January 1, 2023, to December 31, 2024, were extracted from the hospital information management system on January 16, 2025, using structured SQL queries and compiled into a database using Microsoft Excel 2010. Two medical quality managers independently reviewed the medical records to analyze the reasons for unplanned readmissions. Inter-rater reliability was assessed using Cohen’s kappa coefficient (κ = 0.87, 95% CI: 0.827–0.919, p < 0.001), indicating substantial agreement. For cases with inconsistent classifications (n = 27, 7.9% of total cases), a secondary review was conducted to resolve discrepancies. Persistent disagreements (n = 11, 3.2% of total cases) were resolved through consensus discussions with attending physicians to clarify specific readmission etiologies. All data were entered into the database and preliminarily organized to ensure completeness and consistency. A fishbone diagram was used to conduct a root cause analysis of the reasons for unplanned readmission.⁶ Descriptive statistical analysis was used to calculate the proportion and cumulative proportion of unplanned readmissions to quantify the distribution of different causes in readmission events. Subsequently, Pareto chart was constructed based on the above data to analyze the composition of readmission causes. The causes of unplanned readmissions were categorized into three classes: primary factors, with a cumulative proportion of 0% to 80%; secondary factors, with a cumulative proportion of 80% to 90%; and general factors, with a cumulative proportion of 90% to 100%.⁶ The patient selection flowchart and fishbone diagram were generated in Adobe Illustrator CS5, and Pareto chart in Microsoft Excel 2010.

Results

Unplanned Readmission Status

Within 31 days post-discharge, 197 cases were readmitted for the same condition disease, and 144 cases for the related disease. Among 88,701 discharged patients, the cumulative unplanned readmission rate was 0.38% (Figure 1).

Figure 1 Flowchart of Patient Enrollment and Screening Process. The numerator is the sum of Component 1 and Component 2.

Root-Cause Analysis via Fishbone Diagram

A fishbone diagram was employed to conduct root-cause analysis and identify factors contributing to unplanned readmissions (Figure 2). The causes were categorized into three main groups: surgical complications (144 cases, 42.23%), disease exacerbation (138 cases, 40.47%), and pathological findings necessitating reoperation (59 cases, 17.30%).

Figure 2 Root Cause Analysis of Unplanned Readmissions Using a Fishbone Diagram.

Analysis of Readmission Causes in Surgical vs Non-Surgical Patients

Among 57,779 surgical patients, 190 (0.33%) experienced unplanned readmission, with surgical complications being the predominant cause (75.79%). In contrast, of 26,922 non-surgical patients, 151 (0.56%) required unplanned readmission, primarily due to disease exacerbation (72.19%) (Table 1).

Table 1 Analysis of Readmission Causes in Surgical vs Non-Surgical Patients

Pareto Chart Analysis of Surgical Complications

The main types of surgical complications leading to unplanned readmissions were primarily included surgical site infections, respiratory infections, postoperative hemorrhage/hematoma, thromboembolic events, and impaired wound healing, with a cumulative proportion of 81.25%. The secondary types included iatrogenic pneumothorax and postoperative effusion, with a cumulative proportion of 9.03%. The general types accounted for only 9.72% (Figure 3).

Figure 3 Pareto Chart Analysis of Major Surgical Complications Contributing to Unplanned Readmissions. The yellow starburst indicates the 80% cumulative percentage point (Pareto principle). The blue dashed line follows the cumulative curve, identifying the “vital few” complications (left of the threshold) responsible for most readmissions.

High-Risk Diseases for Unplanned Readmissions

Among the 138 cases of unplanned readmissions due to disease exacerbation, pancreatitis, chronic obstructive pulmonary disease, cardiac arrhythmias, and fungal pneumonia were identified as high-risk diseases (Table 2).

Table 2 Analysis of Associated Diseases Due to Exacerbation Leading to Unplanned Readmissions

Discussion

Unplanned readmissions refer to instances where patients are readmitted to the hospital due to relapse of illness, inadequate treatment outcomes, or the emergence of new health issues after discharge. These readmissions are typically associated with the initial disease but are not prearranged. They may reflect issues related to medical quality, patient compliance, or disease complexity and are an important indicator of the quality and efficiency of medical services. Frequent readmissions can impose significant emotional and physical burdens on patients and their families, erode trust in the healthcare system, and increase out-of-pocket expenses for patients as well as resource consumption for healthcare institutions. Reducing hospital readmission rates is crucial for patients, healthcare institutions, and the entire healthcare system.^2,7 Although some readmissions are unavoidable, approximately 27% of readmissions are considered preventable.⁸ Conducting a root cause analysis of unplanned readmissions is essential for developing effective strategies to reduce readmission rates.

A large-scale study incorporating data from 22 hospitals reported a 30-day post-discharge readmission rate of 12.17%.⁹ In contrast, our hospital demonstrated a substantially lower unplanned readmission rate of 0.38%, which may be associated with differences in inclusion/exclusion criteria, hospital capacity, patient case mix, and varying degrees of emphasis on healthcare quality.¹⁰ In our hospital, a root cause analysis of unplanned readmissions was conducted using the six dimensions of a fishbone diagram (people, materials, equipment, methods, environment, and measurement) to systematically identify key factors. These factors included medical record management defects and inadequate treatment and communication skills in hospital personnel; malfunction of implants and drug-related issues in materials; operational failures of medical equipment and resource limitations in equipment; preoperative management, treatment plan selection, and disease management process defects in methods; hospital management regulations, bed shortages, and health policy orientation in environment; and insufficient discharge condition assessment and lagging monitoring in measurement. This comprehensive analysis revealed the complex causes of unplanned readmissions and laid the foundation for hospital management and improvement initiatives.⁷

In our study, surgical complications were identified as the leading cause of unplanned readmissions among surgical patients, accounting for 75.79% of cases. According to the literature, the probability of surgical patients developing infections at or near the surgical incision site is as high as 3%.¹¹ A large retrospective cohort study involving 22,143 patients found that 12% of patients undergoing major surgery experienced unplanned readmission within 90 days post-discharge. Among these cases, wound complications were the most frequent reason for unplanned readmission. Specifically, bowel obstruction or small intestine obstruction was the primary cause after abdominal surgery, pneumonia following thoracic surgery, mechanical complications after orthopedic procedures, and wound complications after cardiac surgery.¹² Another study on colorectal cancer reported a 30-day unplanned readmission rate of 15.1%, with wound infections being the most common diagnosis (27%).¹³ Surgical complications not only result in health and economic losses for patients but also pose potential losses to healthcare institutions. These complications can lead to a reduction in total revenue, as they encroach on the share of higher daily income generated by shorter hospital stays.¹⁴ A thorough analysis of surgical complications can aid in developing targeted intervention measures to reduce readmission rates caused by surgical complications. Our findings indicate that surgical site infections, respiratory infections, postoperative hemorrhage/hematoma, thromboembolic events, and impaired wound healing are the major contributors to readmissions due to surgical complications. Therefore, prevention and management strategies should prioritize these complications, particularly in high-risk populations such as elderly patients and those with significant comorbiditie.¹⁵ From the hospital’s perspective, enhancing surgical proficiency among physicians, rigorously implementing preoperative evaluations, surgical safety checklists, and intraoperative care protocols are key measures for ensuring perioperative safety and effectively mitigating surgical complications.^16–18

Among non-surgical patients, disease exacerbation was the predominant cause of unplanned readmissions, constituting 72.19% of cases. Our study identified pancreatitis, chronic obstructive pulmonary disease (COPD), arrhythmias, and fungal pneumonia as high-risk diseases associated with unplanned readmissions. Acute pancreatitis is a costly and life-threatening condition, with readmission rates ranging from 7% to 34%. The rates vary by etiology: 4–37% for biliary acute pancreatitis, 2–60% for alcohol-induced pancreatitis, and 20–75% for severe or necrotizing pancreatitis. The most common reason for readmission is recurrent acute pancreatitis. Early outpatient follow-up and improved patient-provider communication can reduce readmissions by approximately 20%. Additionally, alcohol cessation, dietary modifications, cholecystectomy, and lipid-lowering therapies are effective strategies to decrease readmission rates.^19,20 COPD affects over 544 million individuals globally and is associated with one of the highest 30-day readmission rates, varying between 2.6% and 82.2% across regions and populations.²¹ Chronic respiratory diseases were the third leading cause of death in 2017, responsible for 7.0% of global mortality. By 2030, COPD and its comorbidities are projected to account for over 4.5 million annual deaths, representing approximately 8.6% of global mortality.²² The readmissions and mortality associated with COPD exacerbations impose substantial economic and emotional burdens on patients and families, significantly impacting public healthcare systems worldwide. Strategies to reduce COPD readmissions should include tobacco control policies, enhanced patient education, and post-discharge follow-up, particularly for high-risk patients with factors such as male sex, prior hospitalization, prolonged hospital stays, and comorbidities including heart failure, cancer, diabetes, and malnutrition.^22,23 For non-surgical patients, reducing unplanned readmissions requires an analysis of institutional case-mix patterns and high-risk conditions. Optimizing in-hospital care and providing tailored discharge guidance are essential to minimizing avoidable readmissions. This study has several limitations. As a single-center retrospective analysis, the findings may lack generalizability due to potential regional variations. Additionally, the relatively short time span of the data collection may limit the assessment of long-term outcomes.

Conclusion

Using fishbone diagram and Pareto chart analyses, this study demonstrates the multidimensional complexity of unplanned readmissions. Enhancing surgical complications prevention and improving the management of high-risk medical conditions are effective strategies to reduce unplanned readmission rates. Our findings provide novel insights for hospital administration, emphasizing the importance of process optimization and quality improvement at the institutional level. Future research should further validate the generalizability of these strategies in multicenter settings to advance continuous healthcare improvement and high-quality development.

Ethical Issues

Ethical approval for this study was obtained from the Ethics Committee of West China Tianfu Hospital, Sichuan University, prior to the commencement of the research (Approval No.: 2024-024). As a retrospective analysis of de-identified patient records, a waiver of informed consent was granted since all protected health information was anonymized prior to data processing. All procedures complied with the ethical standards of the institutional and/or national research committees and adhered to the principles of the Declaration of Helsinki (2013 revision).

Disclosure

The authors report no conflicts of interest in this work.

References

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Background

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder¹ and represents the most common form of motor neuron disease (MND). It is clinically characterized by progressive skeletal muscle weakness, muscular atrophy, fasciculations, bulbar paralysis, and pyramidal tract signs.² Multiple system atrophy (MSA), another neurodegenerative disorder, is characterized by autonomic dysfunction as its core clinical feature and may present with concomitant parkinsonism and/or cerebellar syndrome.³ The early clinical manifestations of ALS are variable, and may include extrapyramidal and autonomic symptoms. Initial symptoms of bulbar paralysis can be easily mistaken for cerebellar ataxia, often leading to misdiagnosis as MSA. Here, we present a case of ALS initially presenting with Parkinsonian features and anxiety, which was misdiagnosed as MSA in the early stages, and analyze the reasons of misdiagnosis. This study proposes an approach for the early identification, diagnosis, and management of ALS in the absence of specific biomarkers.

Case Presentation

History

In 2017, a 54-year-old male patient presented with generalized fatigue and anxiety. In 2018, he developed bradykinesia and postural tremor in the right hand, along with symptoms consistent with rapid eye movement sleep behavior disorder (RBD). He also experienced stool incontinence and urinary urgency, but no olfactory loss, hallucinations, or cognitive impairment were reported. In 2020, the patient’s symptoms worsened, with occasional falls, dysarthria, and urinary incontinence. Physical examination showed normal limb muscle strength, slightly increased muscle tone in the right limb, more pronounced in the lower limbs than the upper limbs, and hyperactive tendon reflexes. Cranial MR revealed mild atrophy of the bilateral frontotemporal lobes (Figure 1). Cervical and lumbar vertebral spinal MR showed no significant abnormalities, and electromyography (EMG) results were within normal limits. In October 2020, positron emission tomography (PET) demonstrated a normal distribution of vesicular monoamine transporter 2 (VMAT2) in the bilateral striatal vesicles, decreased ¹⁸F-FDG metabolism in the left parietal lobe, and increased FDG metabolism in the left posterior putamen (Figure 2). The patient was initially diagnosed with MSA and anxiety. However, levodopa treatment showed no therapeutic effect. In October 2022, the experienced progressive worsening of gait rigidity, accompanied by recurrent falls, dysphagia, and muscle weakness with fasciculations. He was readmitted and ultimately diagnosed with ALS (see event timeline, Figure 3).

Figure 1 MR imaging of the brain 3 years after symptom onset. (a–d) T2 axial view: bilateral frontotemporal lobe atrophy without cerebellar atrophy and hot cross bun sign, (e) T1 axial view: bilateral frontotemporal lobe atrophy.

Figure 2 PET-CT (a and b) there were normal distribution of VMAT2 in caudate nucleus and front or back of the putamen bilateral; (c and d) 18F-FDG revealed that metabolism in the left parietal lobe reduced, whereas that in the left back side of the putamen increased.

Figure 3 History and diagnosis.

Neurological examination revealed no orthostatic hypotension. Tongue atrophy with fibrillation, dysarthria, normal eye movements without nystagmus were noted. Muscle tone was increased in the lower limbs compared to the upper limbs, accompanied by muscle atrophy and hyperactive tendon reflexes in the upper limbs, as well as deltoid muscle atrophy with fasciculations. Distal upper limbs muscle strength was grade 3–4, while lower limb strength was grade 4+. Bilateral Hoffman’s signs and ankle clonus were present. The patient exhibited leg stiffness and a wide-based freezing gait during ambulation. The Romberg and pull-back tests were both positive.

Laboratory test results, including autoantibody profiles and other immune markers, were within normal ranges. The patient tested negative for syphilis and HIV, and his muscle enzyme levels and vitamin concentrations were also normal. Cognitive function assessments, including the Chinese Mini Mental Status (CMMS) and Montreal Cognitive Assessment (MoCA), yielded normal scores. Ultrasonography showed a residual urine volume of 48 mL. EMG revealed neurogenic changes involving the upper and lower limbs as well as the sternocleidomastoid muscles, with fibrillation or fasciculation potentials observed in the medulla, cervical, thoracic, and lumbar regions. Prolonged motor unit action potential (MUAP) duration, increased amplitude, and elevated polyphasic wave percentage were also noted. EMG findings indicated coexistence of acute denervation and chronic neurogenic lesions, while sensory nerve conduction studies were normal. Genetic testing did not identify pathogenic mutations in genes such as SOD-1, TDP-43, or C9orf72.

Following the diagnosis of ALS, riluzole was initiated to slow disease progression. By October 2023, no significant structural changes were observed in the cerebellar brainstem region (Figure 4). The patient was followed up until June 2024 and exhibited increased difficulty in walking, absence of olfactory loss, and improvement in RBD. He remained capable of independent ambulation and showed no signs of orthostatic hypotension.

Figure 4 MR imaging of the brain 6 years after symptom onset. (a and b) T2 axial view: bilateral frontotemporal lobe atrophy, (b and c) T2 axial and sagittal views: no cerebellar atrophy and hot cross bun signs.

Discussion and Conclusions

The patient exhibited motor symptoms one year after initially presenting with fatigue and anxiety, characterized by unilateral bradykinesia and tremor. Parkinson’s disease was excluded due to the normal dopamine transporter function indicated by VMAT2 imaging.⁴ However, a clinically possible diagnosis of MSA could be considered based on the presence of typical RBD, unexplained urinary urgency, and Parkinsonian features, in addition to levodopa insensitivity and lack of characteristic brainstem cross and putaminal fissure signs.³ As the disease progressed, the patient developed typical signs of dysarthria, dysphagia, and fasciculation in the later stages, EMG revealed both upper and lower motor neuron lesions affecting the limbs and sternocleidomastoid muscles, ultimately leading to a diagnosis of ALS.^1,5

The review of the patient’s medical history revealed that his early Parkinsonian features and negative EMG results contributed to the neurologist’s misdiagnosis. Patients with anxiety precursors before motor symptoms are easily misdiagnosed with Parkinson’s syndrome. However, Ibrahim et al⁶ pointed out that emotional instability is a common feature in all patients with MND who are misdiagnosed with Parkinsonism. Considering the broad basis of spastic gait, a combination with dysarthria can easily be mistaken for cerebellar ataxia. In addition, given that the patient exhibited RBD and urinary incontinence in the early stages, he was diagnosed with MSA at several hospitals until he presented with classic fasciculation and muscular atrophy of ALS, as confirmed by EMG. Furthermore, patients with ALS who exhibit prominent pyramidal tract signs may experience sphincter dysfunction.¹ Moreover, bladder symptoms are common in primary lateral sclerosis, which is a type of MND.⁷

Although RBD is a typical non-motor symptom of α-synuclein disease, Zhang et al⁸ reported that some ALS patients still have sleep disorders.⁹ Lo et al¹⁰ also found RBD in of 2/41 patients with ALS and in of 0/26 healthy controls. The cause of RBD in ALS is unknown, but some patients with ALS¹¹ have been confirmed to contain Lewy bodies in their basal glial cells. In addition, both ALS and MSA have pathogenic factors such as mitochondrial dysfunction, neuroinflammation, and oxidative stress.¹² Furthermore, both types of degenerative diseases exhibit abnormal protein folding, which is manifested as alpha-synuclein (α-syn) in MSA, superoxide dismutase 1 (SOD1) and + TAR DNA binding protein (TDP-43) in ALS.¹² Moreover, researchers had identified degenerative pathological changes in the cricoarytenoid muscle fibers of patients with MSA that are similar to those observed in ALS. These changes include abnormalities in synaptic contacts, as well as the loss of synaptic vesicles and mitochondria.^13,14 Perhaps the similarity in the pathological mechanisms of the two neurodegenerative disorders may lead to comparable clinical manifestations.

If the motor and nonmotor symptoms of this patient mimicked MSA, then why did no cerebellar brainstem atrophy or putaminal fissure signs appear in his brain MR images from the onset to 6 years of follow-up? The first and last MR scans revealed signs of bilateral frontotemporal lobe atrophy. Although no signs of frontotemporal dementia were found in this patient, decreased frontotemporal cortex thickness in ALS could explain this sign.¹⁵ In addition, brain PET imaging revealed that ¹⁸F-FDG metabolism in the left parietal lobe of the patient decreased, whereas that in the left posterior putamen increased. This finding contradicts the results of Devrome M.¹⁶ regarding the low metabolism of the striatum in patients with atypical Parkinson’s disease. In addition, Mabuchi et al¹⁷ reported that ¹⁸F-FDG brain PET images in three MND cases suggested widespread frontal hypometabolism with basal ganglial retention.

Although objective examinations can effectively aid in diagnosis, their widespread use in early stages is limited due to the high cost of PET and its unavailability in basic healthcare facilities. In some patients with ALS, MR T2-weighted imaging (T2 WI), fluid-attenuated inversion recovery (FLAIR), and diffusion-weighted imaging (DWI) sequences can reveal highly symmetric signals along the pyramidal tracts, suggesting upper motor neuron involvement¹⁸ but are unnecessary for diagnosis. Elevated levels of cerebrospinal fluid light chains and serum neurofilaments may also indicate upper motor neuronopathy in ALS but lack diagnostic specificity.⁵ Nevertheless, MR remains a valuable tool if it can detect subtle frontotemporal lobe atrophy in the early stages of the disease. Clinicians should also be aware that rigidity observed in ALS originates from pyramidal tract dysfunction. This type of rigidity manifests more as spasticity rather than the lead-pipe or cogwheel rigidity typically seen in parkinsonism, and is generally more pronounced in the lower limbs than in the upper limbs. As illustrated in this case, it may be accompanied by tendon hyperreflexia, which could serve as an early distinguishing feature between ALS and MSA.

In conclusion, not all MNDs are purely confined to the motor system. When they present with extrapyramidal symptoms or Sphincter dysfunction, they are classified as atypical MNDs. Atypical ALS is characterized by a relatively prolonged disease course, and when Parkinsonism and sphincter dysfunction appear in the early stages, it can be easily misdiagnosed as MSA. Although previous studies have documented cases of Primary lateral sclerosis (PLS) mimicking Parkinsonism, there are no published reports describing ALS presenting with symptoms resembling Parkinsonism. Furthermore, in this particular case, the misdiagnosis pertains specifically to MSA, rather than Parkinsonism discussed in earlier literature.^6,17

This study particularly highlights that patients with ALS exhibit high velocity–dependent muscle tension, which is more pronounced in the lower limbs compared to the upper limbs. Early imaging changes, such as mild atrophy of the frontotemporal cortex observed on early MRI and decreased frontoparietal metabolism with preserved basal ganglia function shown on 18F-FDG PET, can serve as key criteria for differentiating ALS from MSA and preventing long-term misdiagnosis.

We anticipate that the development of highly feasible imaging techniques and other biomarkers for ALS will provide robust evidence to support early diagnosis. Consequently, timely treatment can be initiated to improve patients’ quality of life and extend their survival.

Data Sharing Statement

Data is provided within the paper.

Ethics Approval and Consent to Participate

This study has been approved and permitted for publication by the Medical Ethics Committee of Huzhou Central Hospital, and the patient consented to participate.

Consent for Publication

The patient gave written informed consent for his personal or clinical details along with any identifying images to be published in this study.

Acknowledgment

We thank the patients for participating in this study.

Disclosure

The authors report no conflicts of interest.

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