Predicting 30-Day Readmission for Stroke Using Machine Learning Algorithms: A Prospective Cohort Study

Background

Machine learning algorithms for predicting 30-day stroke readmission are rarely discussed. The aims of this study were to identify significant predictors of 30-day readmission after stroke and to compare prediction accuracy and area under the receiver operating characteristic (AUROC) curve in five models: artificial neural network (ANN), K nearest neighbor (KNN), random forest (RF), support vector machine (SVM), naive Bayes classifier (NBC), and Cox regression (COX) models.

Methods

The subjects of this prospective cohort study were 1,476 patients with a history of admission for stroke to one of six hospitals between March, 2014, and September, 2019. A training dataset (n = 1,033) was used for model development, and a testing dataset (n = 443) was used for internal validation. Another 167 patients with stroke recruited from October, to December, 2019, were enrolled in the dataset for external validation. A feature importance analysis was also performed to identify the significance of the selected input variables.

Results

For predicting 30-day readmission after stroke, the ANN model had significantly (P < 0.001) higher performance indices compared to the other models. According to the ANN model results, the best predictor of 30-day readmission was PAC followed by nasogastric tube insertion and stroke type (P < 0.05). Using a machine learning ANN model to obtain an accurate estimate of 30-day readmission for stroke and to identify risk factors may improve the precision and efficacy of management for these patients.

Conclusion

Using a machine-learning ANN model to obtain an accurate estimate of 30-day readmission for stroke and to identify risk factors may improve the precision and efficacy of management for these patients. For stroke patients who are candidates for PAC rehabilitation, these predictors have practical applications in educating patients in the expected course of recovery and health outcomes.

Cost Utility Analysis of Multidisciplinary Postacute Care for Stroke: A Prospective Six-Hospital Cohort Study

Background

Few studies have compared the optimal duration and intensity of organized multidisciplinary neurological/rehabilitative care delivered in a regional/district hospital with the standard rehabilitative care delivered in the general neurology/rehabilitation ward of a medical center. This study measured functional outcomes and conducted cost-utility analysis of an organized multidisciplinary postacute care (PAC) project in secondary care compared with standard rehabilitative care delivered in tertiary care.

Methods

This prospective cohort study enrolled 1,476 patients who had a stroke between March 2014 and March 2018 and had a modified Rankin scale score of 2–4. After exact matching for age ± 1 year, sex, year of stroke diagnosis, nasogastric tube, and Foley catheter and propensity score matching for the other covariates, we obtained 120 patients receiving PAC (the PAC group) from four regional/district hospitals and 120 patients not receiving PAC (the non-PAC group) from two medical centers.

Results

At baseline, the non-PAC group showed significantly better functional outcomes than the PAC group, including EuroQol-5 dimensions (EQ-5D), Mini-Mental State Examination (MMSE) and Barthel index (BI). During weeks 7–12 of rehabilitation, improvements in all functional outcomes were significantly larger in the PAC group (P < 0.001) except for Functional Oral Intake Scale (FOIS). Cost-utility analysis revealed that the PAC group had a significantly lower mean (± standard deviation) of direct medical costs (US$3,480 ± $1,758 vs. US$3,785 ± $3,840, P < 0.001) and a significantly higher average gain of quality-adjusted life years (0.1993 vs. 0.1233, P < 0.001). The PAC project was an economically “dominant” strategy.

Conclusions

The PAC project saved costs and significantly improved the functional outcomes of patients with stroke with slight to moderately severe disabilities. Randomized control trials are required to corroborate these results.

High 18F-fluoro-2-deoxy-D-glucose uptake in adult-type rhabdomyoma of the larynx

Rhabdomyomas are rare benign mesenchymal tumors of the skeletal muscles and uncommon in the head and neck region. Laryngeal rhabdomyomas are much rarer. We present the case of a 32-year-old woman who was admitted to our hospital for shortness of breath due to pneumothorax. As otolaryngologists, we were consulted for a soft tissue tumor over the left side of the larynx that was accidentally found on the chest computed tomography (CT). The patient underwent laryngomicrosurgery for tumor biopsy, and histological examination revealed a laryngeal rhabdomyoma. After the operation, magnetic resonance imaging of the neck was performed and the tumor was suspected as rhabdomyosarcoma. Positron emission tomography/computed tomography (PET/CT) showed an 18F-fluoro-2-deoxy-D-glucose (FDG)-avid soft tissue mass on the left side of the larynx. After complete tumor removal via transoral laser microsurgery, no recurrence was reported for 5 years.

Multidisciplinary Care after Acute Care for Stroke: A Prospective Comparison between a Multidisciplinary Post-Acute Care Group and a Standard Group Matched by Propensity Score

In this large-scale prospective cohort study, a propensity score matching method was applied in a natural experimental design to investigate how post-acute care (PAC) after stroke affects functional status and to identify predictors of functional status. The main objective of this study was to examine longitudinal changes in various measures of functional status in stroke patients and predictors of scores for these measures before and after PAC. A group of patients who had received PAC for stroke at one of two medical centers (PAC group, n = 273) was compared with a group who had received standard care for stroke at one of four hospitals (three regional hospital and one district hospital; non-PAC group, n = 273) in Taiwan from March, 2014, to October, 2018. The patients completed the functional status measures before rehabilitation, the 12th week and the 1st year after rehabilitation. Generalized estimating equations were used to estimate differences-in-differences models for examining the effects of PAC. The average age was 68.0 (SD = 8.1) years, and males accounted for 57.9%. During the follow-up period, significant risk factors for poor functional outcomes were advanced age, hemorrhagic stroke, and poor function scores before rehabilitation (p < 0.05). Between-group comparisons at subsequent time points revealed significantly higher functional status scores in the PAC group versus the non-PAC group (p < 0.001). Notably, for all functional status measures, between-group differences in total scores significantly increased over time from baseline to 1 year post-rehabilitation (p < 0.001). The contribution of this study is its further elucidation of the clinical implications and health policy implications of rehabilitative care after stroke. Specifically, it improves understanding of the effects of PAC in stroke patients at different follow-up times. Therefore, a policy implication of this study is that standard care for stroke should include intensive rehabilitative PAC to maximize recovery of overall function.

Impact of Multidisciplinary Stroke Post-Acute Care on Cost and Functional Status: A Prospective Study Based on Propensity Score Matching

Few papers discuss how the economic burden of patients with stroke receiving rehabilitation courses is related to post-acute care (PAC) programs. This is the first study to explore the economic burden of stroke patients receiving PAC rehabilitation and to evaluate the impact of multidisciplinary PAC programs on cost and functional status simultaneously. A total of 910 patients with stroke between March 2014 and October 2018 were separated into a PAC group (at two medical centers) and a non-PAC group (at three regional hospitals and one district hospital) by using propensity score matching (1:1). A cost-illness approach was employed to identify the cost categories for analysis in this study according to various perspectives. Total direct medical cost in the per-diem-based PAC cohort was statistically lower than that in the fee-for-service-based non-PAC cohort (p < 0.001) and annual per-patient economic burden of stroke patients receiving PAC rehabilitation is approximately US $354.3 million (in 2019, NT $30.5 = US $1). Additionally, the PAC cohort had statistical improvement in functional status vis-à-vis the non-PAC cohort and total score of each functional status before rehabilitation and was also statistically significant with its total score after one-year rehabilitation training (p < 0.001). Early stroke rehabilitation is important for restoring health, confidence, and safe-care abilities in these patients. Compared to the current stroke rehabilitation system, PAC rehabilitation shortened the waiting time for transfer to the rehabilitation ward and it was indicated as an efficient policy for treatment of stroke in saving medical cost and improving functional status.

Backbone resonance assignments of the PRYSPRY domain of TRIM25

TRIM25 is a member of the tripartite motif (TRIM) family and has been implicated in the regulation of innate immune signaling via the RIG-I (retinoic acid-inducible gene-I) pathway for antiviral defense. As the essential first step towards the structural and functional characterization of the TRIM25/RIG-I interaction, the backbone resonance of the PRYSPRY domain of TRIM25 is assigned here based on triple-resonance experiments using uniformly [(2)H, (13)C, (15)N]-labeled protein.

Prevalence, incidence, and comorbidity of clinically diagnosed obsessive-compulsive disorder in Taiwan: a national population-based study

Obsessive-compulsive disorder (OCD) is a chronic debilitating anxiety disorder significant in intrusive thoughts and compensation repetitive behaviors. Few studies have reported on this condition Asia. This study estimated the prevalence, incidence and psychiatric comorbidities of OCD in Taiwan. We identified study subjects for 2000-2008 with a principal diagnosis of OCD according to the International Classification of Disease, 9th Revision, Clinical Modification (ICD-9-CM) diagnostic criteria by using National Health Research Institute database. These patients received either outpatient or inpatient care for their condition. Rates were directly age- and sex-adjusted to the 2004 Taiwan population distribution. The estimated mean annual incidence was 27.57 per 10(5) inhabitants and the one year prevalence was 65.05 per 10(5) inhabitants. Incidence and prevalence increased with age, peaking at age 18-24 years in males and at 35-44 years in females. About 53% of adults (≥18 years) and 48% of child and adolescent patients (6-17 years) had one or more comorbid psychiatric conditions. The most common comorbid diagnosis was depressive disorders for both adult and child-adolescent patients. We found a lower prevalence and incidence of clinically diagnosed OCD than that of community studies. Many Asian patients with OCD also had various psychiatric comorbidities, a clinically relevant finding.

¹H, ¹³C and ¹⁵N resonance assignments of Ca²⁺-bound human S100A15

S100A15 (koebnerisin) is overexpressed in psoriatic skin and displays distinct localizations in skin and breast with divergent functions in inflammation. Here we report the backbone and side-chain resonance assignments for the Ca(2+)-bound human S100A15.

Nuclear magnetic resonance structure of the cytoplasmic tail of heparin binding EGF-like growth factor (proHB-EGF-CT) complexed with the ubiquitin homology domain of Bcl-2-associated athanogene 1 from Mus musculus (mBAG-1-UBH)

The membrane form of heparin binding EGF-like growth factor (proHB-EGF) yields secreted HB-EGF and a membrane-anchored cytoplasmic tail (proHB-EGF-CT), which may be targeted to the nuclear membrane after a shedding stimulus. Bcl-2-associated athanogene 1 (BAG-1) accumulates in the nuclei and inhibits apoptosis in adenoma-derived cell lines. The maintenance of high levels of nuclear BAG-1 enhances cell survival. However, the ubiquitin homology domain of BAG-1 from Mus musculus (mBAG-1-UBH) is proposed to interact with proHB-EGF-CT, and this interaction may enhance the cytoprotection against the apoptosis inducer. The mechanism of the synergistic anti-apoptosis function of proHB-EGF-CT and mBAG-1-UBH is still unknown. We offer a hypothesis that proHB-EGF-CT can maintain high levels of nuclear BAG-1. In this study, we first report the three-dimensional nuclear magnetic resonance structure of proHB-EGF-CT complexed with mBAG-1-UBH. In the structure of the complex, the residues in the C-terminus and one turn between β-strands β1 and β2 of mBAG-1-UBH bind to two terminals of proHB-EGF-CT, which folds into a loop with end-to-end contact. This end-to-end folding of proHB-EGF-CT causes the basic amino acids to colocalize and form a positively charged groove. The dominant forces in the binding interface between proHB-EGF-CT and mBAG-1-UBH are charge-charge interactions. On the basis of our mutagenesis results, the basic amino acid cluster in the N-terminus of proHB-EGF-CT is the crucial binding site for mBAG-1-UBH, whereas another basic amino acid in the C-terminus facilitates this interaction. Interestingly, the mBAG-1-UBH binding region on the proHB-EGF-CT peptide is also involved in the region found to be important for nuclear envelope targeting, supporting the hypothesis that proHB-EGF-CT is most likely able to trigger the nuclear translocation of BAG-1 in keeping its level high.

Mood disorders after traumatic brain injury in adolescents and young adults: a nationwide population-based cohort study

OBJECTIVE

To delineate the relationship between traumatic brain injury (TBI) and mood disorders from population-based data in Taiwan.

STUDY DESIGN

This prospectively followed cohort study involved a subset of the National Health Insurance Research Database containing complete inpatient and outpatient data of 1 million randomly drawn beneficiaries. We included 10- to 24-year-old patients (n = 15,203) receiving the diagnosis of TBI in ambulatory visits or hospitalization from 2000-2004 and their age- and sex-matched comparison insureds using health service in the same year (n = 76,015). Diagnosis of mood disorders was recorded within 5 years after the traumatic event or index use of health service. Baseline demographics, clinical characteristics, and premorbid psychiatric conditions were compared using χ(2) analysis. Increased risk during the 5-year follow-up period was represented by crude and adjusted hazard ratios with 95% CI using a Cox proportional hazard regression.

RESULTS

A total of 451/15,203 patients with TBI (2.97%) received a diagnosis of mood disorders in the 5-year follow-up period compared with 1153/97,445 individuals (1.52%) without antecedent TBI. After adjusting for select premorbid comorbidities, TBI remained a significant predisposing factor with a 1.96-fold (95% CI 1.74-2.22) increase in risk of mood disorders.

CONCLUSIONS

Our findings show a higher likelihood of manifesting mood disorders in adolescents and young adults who sustained a prior TBI. Health professionals should carefully monitor both the physical and psychological impacts of head trauma.

Resonance assignments of Ca²⁺-bound human S100A11

The S100 family belongs to the EF-hand calcium-binding proteins regulating a wide range of important cellular processes via protein-protein interactions. Most S100 proteins adopt a conformation of non-covalent homodimer for their functions. Calcium binding to the EF-hand motifs of S100 proteins is essential for triggering the structural changes, promoting exposure of hydrophobic regions necessary for target protein interactions. S100A11 is a protein found in diverse tissues and possesses multiple functions upon binding to different target proteins. RAGE is a multiligand receptor binding to S100A11 and the interactions at molecular level have not been reported. However, the three-dimensional structure of human S100A11 containing 105 amino acids is still not available for further interaction studies. To determine the solution structure, for the first time we report the (1)H, (15)N and (13)C resonance assignments and protein secondary structure prediction of human S100A11 dimer in complex with calcium using a variety of triple resonance NMR experiments and the chemical shift index (CSI) method, respectively.

Population based study on patients with traumatic brain injury suggests increased risk of dementia

OBJECTIVE

The relationship between traumatic brain injury (TBI) and the risk of dementia remains controversial. This population based study was designed to estimate and compare the risk of dementia in TBI and non-TBI individuals during the 5 year period after TBI.

METHODS

This study was a retrospective cohort study. Data were obtained from the Longitudinal Health Insurance Database 2000. We included 44,925 patients receiving ambulatory or hospital care and 224,625 non-TBI patients; patients were matched for sex, age and year of index use of healthcare. Patients <15 years of age and those admitted to the intensive care unit were excluded. Each individual was studied for 5 years to identify the subsequent development of dementia. Data were analysed by Cox proportional hazard regression.

RESULTS

During the 5 year follow-up period, 1196 TBI (2.66%) and 224,625 non-TBI patients (1.53%) patients developed dementia. During the 5 year follow-up period, TBI was independently associated with a 1.68 (range 1.57-1.80) times greater risk of dementia after adjusting for sociodemographic characteristics and selected comorbidities.

CONCLUSIONS

The findings of this study suggest an increased risk of dementia among individuals with TBI. We suggest the need for more intensive medical monitoring and health education in individuals with TBI.

Structural fold, conservation and Fe(II) binding of the intracellular domain of prokaryote FeoB

FeoB is a G-protein coupled membrane protein essential for Fe(II) uptake in prokaryotes. Here, we report the crystal structures of the intracellular domain of FeoB (NFeoB) from Klebsiella pneumoniae (KpNFeoB) and Pyrococcus furiosus (PfNFeoB) with and without bound ligands. In the structures, a canonical G-protein domain (G domain) is followed by a helical bundle domain (S-domain), which despite its lack of sequence similarity between species is structurally conserved. In the nucleotide-free state, the G-domain's two switch regions point away from the binding site. This gives rise to an open binding pocket whose shallowness is likely to be responsible for the low nucleotide-binding affinity. Nucleotide binding induced significant conformational changes in the G5 motif which in the case of GMPPNP binding was accompanied by destabilization of the switch I region. In addition to the structural data, we demonstrate that Fe(II)-induced foot printing cleaves the protein close to a putative Fe(II)-binding site at the tip of switch I, and we identify functionally important regions within the S-domain. Moreover, we show that NFeoB exists as a monomer in solution, and that its two constituent domains can undergo large conformational changes. The data show that the S-domain plays important roles in FeoB function.

Solution structure of the ligand binding domain of the fibroblast growth factor receptor: role of heparin in the activation of the receptor

The three-dimensional solution structure of the ligand binding D2 domain of the fibroblast growth factor receptor (FGFR) is determined using multidimensional NMR techniques. The atomic root-mean-square distribution for the backbone atoms in the structured region is 0.64 A. Secondary structural elements in the D2 domain include 11 beta-strands arranged antiparallely into two layers of beta-sheets. The structure of the D2 domain is characterized by the presence of a short flexible helix that protrudes out of the layers of beta-sheets. Results of size exclusion chromatography and sedimentation velocity experiments show that the D2 domain exists in a monomeric state both in the presence and in the absence of bound sucrose octasulfate (SOS), a structural analogue of heparin. Comparison of the solution structure of the D2 domain with the crystal structure of the protein (D2 domain) in the FGF signaling complex reveals significant differences, suggesting that ligand (FGF) binding may induce significant conformational changes in the receptor. SOS binding sites in the D2 domain have been mapped on the basis of the 1H-15N chemical shift perturbation data. SOS binds to the positively charged residues located in beta-strand III and the flexible helix. Isothermal titration calorimetry data indicate that the ligand (hFGF-1) binds strongly (Kd approximately 10(-9) M) to the D2 domain even in the absence of SOS. Binding of SOS to either the D2 domain or hFGF-1 does not seem to be the driving force for the formation of the D2-hFGF-1 binary complex. The function of SOS binding appears to stabilize the preformed D2-FGF binary complex.

Molecular cloning, overexpression, and characterization of the ligand-binding D2 domain of fibroblast growth factor receptor

Fibroblast growth factors (FGFs) regulate a wide range of important cellular processes. The biological activities of FGFs are mediated by cell surface receptors (FGFRs). In the present study for the first time we report the cloning, expression, and characterization of the ligand (FGF)-binding D2 domain of human FGFR2. D2 domain is expressed in Escherichia coli in high yields (10 mg/L) as inclusion bodies. The protein is recovered by dissolving the inclusion bodies in 8 M urea and subsequently refolding on nickel affinity column. The protein is purified (to approximately 97% purity) to homogeneity using heparin-Sepharose affinity column. Far-UV circular dichroism data and chemical shift index plot based on 1H-alpha, 13C-alpha, 13C-beta, and 13carbonyl group chemical shifts suggest that D2 domain is an all beta-sheet protein consisting of 9 beta-strands. Isothermal titration calorimetry and equilibrium urea unfolding experiments show that recombinant D2 domain is in a biologically active conformation and binds strongly to its ligand (FGF) and to the heparin analog, sucrose octasulfate (SOS). Using a variety of triple resonance NMR experiments, complete assignment of 1H, 15N, and 13C resonances in D2 domain has been accomplished. The findings of the present study not only pave way for an in-depth investigation of the molecular mechanism(s) underlying the activation of FGF signaling but also provide avenues for the rational design of potent inhibitors against FGF-mediated pathogenesis.

Comparison of the structural stability of two homologous toxins isolated from the Taiwan cobra (Naja naja atra) venom

Cardiotoxin analogue III (CTX III) and cobrotoxin (CBTX) isolated from the Taiwan cobra venom (Naja naja atra) are structurally homologous, small molecular weight, all-beta-sheet proteins, cross-linked by four disulfide bonds at identical positions. The conformational stabilities of these toxins are compared based on temperature-dependent chemical shifts and amide proton exchange kinetics using two-dimensional NMR spectroscopy. The structure of CTX III is found to be significantly more stable than that of CBTX. In both the toxins, beta-strand III appears to constitute the stability core. In CTX III, the stability of the triple-stranded beta-sheet domain is observed to be markedly higher than the double-stranded beta-sheet segment. In contrast, in CBTX, both structural domains (double- and triple-stranded beta-sheet domains) appear to contribute equally to the stability of the protein. Estimation of the free energy of exchange (Delta G(ex)) of residues in CBTX and CTX III reveals that the enhanced stability of the structure of CTX III stems from the strong interactions among the beta-strands constituting the triple-stranded beta-sheet domain and also the molecular forces bridging the residues at the N- and C-terminal ends of the molecule.

Influence of disulfide bonds on the induction of helical conformation in proteins

The effect(s) of TFE (2,2,2-trifluoroethanol) on three different conformational states (native, denatured, and carboxymethylated) of CTX III and RNase A has been examined. Contrary to the general belief, the results of the present study reveal that TFE can induce helical conformation in a protein which has no sequence propensity to form a helix. It is found that the helix induction in TFE is intricately related to the destabilization of the tertiary structural conformation in proteins. More importantly, the disulfide bonds in proteins are found to have significant influence on the TFE-mediated helix induction. The results obtained in this study strongly suggest that information pertaining to the influence of disulfide bonds on helix induction need to be considered to improve the accuracy of secondary structure prediction algorithms.