Cross-National Disparities in End-of-Life Outcomes and Care Strategies for Parkinson's Disease: A Systematic Review and Meta-Analysis of China and the United States
Abstract Background Parkinson's disease (PD) represents a growing global health challenge, with prevalence doubling from 2.5 million cases in 1990 to 6.1 million in 2016, and projections suggesting it will exceed 12 million by 2040. This exponential growth has been termed the "Parkinson's pandemic." China and the United States, which together account for nearly half of the global PD population, have developed markedly different approaches to end-of-life (EOL) care, shaped by their distinct healthcare systems and cultural contexts. Understanding these differences is crucial for developing effective global strategies. This systematic review and meta-analysis comprehensively compares advanced-stage PD care between these two nations to quantify disparities and inform evidence-based policy interventions. Methods We conducted a rigorous systematic review following PRISMA 2020 guidelines, searching six databases (PubMed, Embase, Scopus, Web of Science, CNKI, Wanfang) from January 2015 to October 2025. The timeframe was selected to capture contemporary care patterns following major healthcare reforms in both countries (Affordable Care Act implementation in the US; Healthy China 2030 initiative). Inclusion criteria encompassed peer-reviewed studies reporting on advanced PD (Hoehn-Yahr stage ≥ 3) with outcome measures including survival, quality of life (QoL), palliative care access, caregiver burden, rehabilitation utilization, or healthcare costs. The sample size threshold (n ≥ 100) balanced statistical power with inclusivity. Two independent reviewers screened 3,847 records with excellent agreement (Cohen's κ = 0.82–0.89). Quality assessment employed the Newcastle-Ottawa Scale (NOS ≥ 8 indicating high quality) and ROBINS-I for observational studies, with GRADE criteria determining evidence certainty. Meta-analyses utilized random-effects models with comprehensive heterogeneity assessment (I² statistics, meta-regression) and publication bias evaluation (Egger's test, trim-and-fill analysis). Sensitivity analyses included high-quality studies only and examined the influence of large database studies. Results Our analysis of 42 high-quality studies encompassing over 125,000 patients revealed profound and systematic cross-national disparities across multiple domains. In terms of care access, US patients demonstrated significantly higher hospice enrollment rates (28–35% vs. <1% in China, p < 0.001; HIGH certainty evidence) and greater access to specialized neuropalliative programs (15% of US centers vs. <1% in China). These differences translated into measurable quality of life disparities, with Chinese patients scoring 17.6 points worse on the PDQ-39 scale (95% CI 14.2–21.0; MODERATE certainty, I²=68%), a difference exceeding the minimal clinically important difference nearly four-fold. The burden on families showed equally striking patterns: Chinese families provided 94% of EOL care compared to 61% in the US, resulting in significantly higher caregiver depression rates (47% vs. 32%, OR = 1.89, 95% CI 1.45–2.47) and burden scores (Zarit difference: 10.2 points, 95% CI 7.8–12.6). Access to interventions revealed additional gaps, with only 9.2% of Chinese patients receiving physical therapy versus 14.4% in the US (OR = 0.61, 95% CI 0.49–0.76), and a 5.25-fold disparity in deep brain stimulation access (4.2% vs. 0.8%). Economic analysis demonstrated substantial out-of-pocket burden differences: Chinese families paid 58% of total costs ($4,200 annually) versus 12% for US families ($2,800). Meta-regression identified healthcare system characteristics as the primary driver of these disparities (R²=0.42, p < 0.001). Conclusions This comprehensive analysis reveals that systematic differences in healthcare infrastructure, insurance coverage, and cultural care models produce markedly divergent EOL experiences for PD patients in China versus the United States. These findings have immediate policy implications. For China, we recommend: (1) establishing pilot neuropalliative programs in tertiary centers with phased national expansion; (2) developing caregiver support infrastructure including respite care and training programs; (3) leveraging telemedicine platforms to address urban-rural disparities. For the United States, priorities include: (1) addressing racial disparities in rehabilitation access through culturally competent outreach; (2) expanding Medicare coverage for maintenance therapy; (3) earlier integration of neuropalliative care. Implementation science research is urgently needed to test culturally adapted interventions. As global PD prevalence accelerates, lessons from this bilateral comparison provide a framework for other nations confronting similar challenges in neurological care delivery.
Modulation of Autonomic Function and Heart Rate Variability by Transcutaneous Spinal Cord Stimulation and Physical Therapy in Individuals with Chronic Spinal Cord Injury
Abstract Background Spinal cord injury causes motor, sensory, and autonomic impairments. Transcutaneous spinal cord stimulation (tSCS) has shown potential to improve autonomic regulation, particularly cardiovascular and bladder control. Heart rate variability (HRV) serves as a non-invasive marker of autonomic balance, reflecting modulation of cardiac sympathetic and parasympathetic activity. The purpose of this study was to evaluate the effect of combined tSCS and physical therapy (tSCS + PT) on HRV and autonomic function metrics in chronic spinal cord injury. Methods. Eight participants (2 with tetraplegia, 6 with paraplegia) received tSCS at 30 Hz targeting T11–L1 or C5–T1, depending on injury level. Each underwent two tSCS + PT sessions per week for 12 weeks, followed by a 4-week washout period. Autonomic assessments included the Autonomic Standard Evaluation Form (ASAF), Neurologic Bladder Symptoms Score (NBSS), blood pressure, heart rate, SpO2%, and core temperature. Electrocardiograms were recorded pre- and post-tSCS + PT at baseline, 12, and 16 weeks. Results. Baseline effects of tSCS + PT revealed increased time-domain HRV parameters, suggesting enhanced cardiac parasympathetic activation (PSA). After 12 weeks, these parameters decreased, suggesting reduced cardiac PSA and enhanced sympathetic activation (SA). Similar results were found with frequency-domain parameters. Time-and frequency-domain parameters tended to return toward baseline after the 4-week therapy suspension. Two commonly reported HRV parameters, SDNN and RMSSD, showed large effects (g = 1.64, CI 95% [0.30, 2.98], and g = 1.23, CI 95% [0.11, 2.42], respectively) at 12 weeks when comparing pre- vs. post-tSCS + PT. Moderate, subject-related differences across evaluations were found in ASAF and NBSS (p > 0.05). Physiological metrics across time points did not show statistically significant differences (p > 0.05). Physiological metrics across time points did not show statistically significant differences (p > 0.05). Conclusions Combined tSCS + PT elicited improvements in autonomic clinical measures, without statistically significant changes in time-domain or frequency-domain HRV parameters. Nonetheless, trends and size effect in SDNN and RMSSD suggested that tSCS + PT induced midterm SA and a transient PSA immediately post-tSCS + PT. The partial recovery of HRV after tSCS withdrawal indicates that the observed autonomic changes were therapy-related.
The Anxious Bipolar Phenotype: Clinical Complexity and Treatment Resistance
Abstract Background Anxiety disorders (ANX) affect 30–60% of individuals with bipolar disorder (BD), yet limited research has systematically examined clinical characteristics and treatment patterns in this comorbid population. This study investigated demographic, clinical, and pharmacotherapeutic differences between individuals with BD with and without comorbid ANX. Methods Cross-sectional data from 2,225 adults with BD enrolled in the Mayo Clinic Bipolar Disorder Biobank were analyzed. Participants were assessed for comorbid ANX, demographics, clinical characteristics, medication use, and treatment response using the Alda-A scale. Results Overall, 61% (n = 1,366) had comorbid ANX. Individuals with BD + ANX were younger (40.4 vs. 43.6 years, p < 0.001), more likely female (66.6% vs. 54.8%, p < 0.001), and exhibited higher rates of rapid cycling (64.2% vs. 45.2%, p < 0.001), suicide attempts (40.4% vs. 24.8%, p < 0.001), substance use disorders (63.5% vs. 54.8%, p < 0.001), and somatic comorbidities (MCIRS: 6.68 vs. 5.42, p < 0.001). Pharmacotherapeutically, BD + ANX individuals were less likely to receive lithium (37.1% vs. 47.8%, p = 0.005) and valproic acid (21.7% vs. 29.6%, p = 0.047), but more likely to receive antidepressants (53.8% vs. 39.5%, p < 0.001), benzodiazepines (39.9% vs. 26.6%, p < 0.001), and gabapentinoids (8.5% vs. 4.5%, p < 0.001). Notably, 17.3% of BD + ANX individuals received antidepressants without mood stabilizer coverage. Treatment response (Alda-A) scores were significantly lower in BD + ANX for lithium (4.91 vs. 6.05, p < 0.001), mood-stabilizing anticonvulsants (5.09 vs. 6.22, p < 0.001), and second-generation antipsychotics (4.67 vs. 5.73, p < 0.001). Similar patterns were observed in both BD-I and BD-II subtypes. Conclusions Individuals with BD + ANX represent a more severely affected subgroup with distinct prescribing patterns favoring antidepressants over mood stabilizers and attenuated mood stabilizers response. These findings highlight the need for anxiety-informed treatment algorithms recognizing anxiety comorbidity as a negative prognostic factor.
Association Between High-Flow Nasal Cannula Use for Bronchiolitis and Subsequent Asthma Diagnosis
BACKGROUND High-flow nasal cannula (HFNC) therapy is widely used in infants hospitalized with moderate-to-severe bronchiolitis. Although bronchiolitis severity has been consistently associated with later asthma, it remains unclear whether HFNC contributes additional risk or instead represents a marker of severe illness. We examined the relationship between HFNC use during bronchiolitis hospitalization and the subsequent hazard of asthma diagnosis in early childhood. METHODS We conducted a retrospective cohort study of 4736 children aged younger than 2 years hospitalized with bronchiolitis from 2015 to 2023 across 2 tertiary children’s hospitals. Children were stratified by HFNC exposure. Cox proportional hazards models evaluated the association between HFNC use and subsequent asthma diagnosis. Secondary analyses assessed HFNC duration and frequency. RESULTS Forty-three percent of children received HFNC. Asthma was subsequently diagnosed in 37% of HFNC-treated children and 22% of non-HFNC children (P < .001). After adjustment for demographic and clinical variables, HFNC use was associated with a 40% increased hazard of subsequent asthma diagnosis (hazard ratio, 1.40; 95% CI, 1.24–1.57; P < .001). No dose-response pattern was observed by HFNC duration or frequency. CONCLUSION HFNC use was associated with an increased hazard of subsequent diagnosis of asthma in childhood, likely reflecting underlying disease severity rather than a treatment-related effect. Prospective studies are needed to differentiate severity-related risk from treatment-associated factors to optimize respiratory support strategies for infants with bronchiolitis.
Immune Checkpoint Inhibitor-Induced Cardiovascular Disease: The Role of Accelerated Senescence in Vascular Dysfunction
Significance: Immune checkpoint inhibitors (ICIs) have transformed cancer therapy by reactivating antitumor immunity and improving outcomes across multiple malignancies. Yet, clinical observations and preclinical studies suggest that ICIs may increase long-term cardiovascular disease risk, including hypertension, atherosclerosis, and thrombosis. The underlying mechanisms remain incompletely defined, highlighting the need for focused investigation into the vascular consequences of immune activation. Recent Advances: ICI-induced immune activation disrupts vascular and immune homeostasis through persistent production of reactive oxygen species (ROS), mitochondrial dysfunction, and accumulation of cell-free DNA (cfDNA). Sustained T-cell activation enhances ROS generation, driving DNA damage and senescence in both endothelial and immune cells. ICIs may also promote endothelial-to-mesenchymal transition (EndoMT) through chronic oxidative and inflammatory signaling, contributing to fibrosis, vascular stiffness, and chronic inflammation. Transforming growth factor-beta, although immunosuppressive in many contexts, can drive profibrotic and EndoMT programs within the vasculature. Other cytokines and regulators, including interleukin-17 and regulator of calcineurin 1, have been implicated in vascular remodeling, atherosclerosis, and hypertension. Critical Issues: The relative roles of ROS, mitochondrial dysfunction, cfDNA-driven inflammation, and EndoMT in ICI-associated vascular senescence remain unclear. While inflammation-induced vascular damage is well-recognized, direct ICI-specific mechanisms require stronger evidence. How senescent endothelial and immune cells influence therapy resistance and remodeling of the tumor microenvironment also remains to be defined. Future Directions: Mitochondrial and cytosolic ROS sources—arising from electron leakage during oxidative phosphorylation and NADPH oxidases activity—shape immune signaling and sustain T-cell activation during checkpoint blockade. The DNA damage response kinases ataxia-telangiectasia mutated and ATM- and Rad3-related, activated by oxidative and replicative stress, engage p53-dependent senescence pathways in endothelial and immune cells. Future studies should evaluate biomarkers such as cfDNA and thrombospondin-1 and explore senescence-targeting or redox-modulating interventions that may alleviate cardiovascular toxicity without diminishing antitumor efficacy. This review outlines mechanistic pathways linking ICIs to vascular dysfunction and senescence, integrating preclinical data with emerging clinical insights. It distinguishes established processes from ICI-specific hypotheses and identifies key gaps requiring clinical validation. Antioxid. Redox Signal. 00, 000–000.
PART characterization using MK‐6240 and Flortaucipir
Abstract Background Older adults with brain tau pathology but no evident amyloid‐beta (A) pathology can be referred to as primary age‐related tauopathy (PART). However, in vivo characterization of PART using biomarkers remains unclear, varying based on the method used to define tau pathology (e.g. different tau‐PET tracers). Here, we conducted a head‐to‐head characterization of PART using two different tau‐PET tracers. Method We studied 433 individuals from the HEAD cohort (244 CU, 138 MCI, and 51 with dementia). Participants underwent clinical assessments, MRI, A‐PET, both MK‐6240 and Flortaucipir scans, and a subset with plasma biomarkers ( n = 332). A‐PET positivity was defined as Centiloid>24. Tau‐positivity(T) was determined by MK‐6240 and Flortaucipir SUVR values exceeding the mean+2SD in at least one Braak region anchored in CU A‐ individuals followed by visual confirmation in A‐/T+ cases. Concordance across biomarkers was assessed among PART (A‐/T+), A‐/T‐ and A+/T+ groups. Plasma GFAP, p ‐tau217, NFL levels, and Centiloids were compared across A/T groups using linear regression. Result We found a total of 25 (5.8 %) cases classified as A‐/T+ defined by at least one tau tracer (74±6.3 years, 52% females, 17 CU, 3 MCI, 5 with dementia). Detection of A‐/T+ cases varied by tracer: MK‐6240( n = 20), Flortaucipir( n = 16) (Figure 1A). Among A‐/T+ individuals, MK‐6240 identified 13 CU, 4 MCI, and 3 dementia cases, while Flortaucipir identified 11 CU, 3 MCI, and 2 dementia cases(Figure 1B). Concordance between MK‐6240 and Flortaucipir in A‐/T+ cases was low ( n = 11, 44%)(Figure 1C). A‐/T+ individuals showed no significant biomarker differences from A‐/T‐ but had lower biomarker levels than A+/T+: Centiloids (MK‐6240: T=15.08, p <0.001; Flortaucipir: T=14.36, p <0.001), GFAP (MK‐6240: T=5.04, p < 0.01; Flortaucipir: T=2.92, p <0.001), p ‐tau217 (MK‐6240: T=7.77, p <0.001; Flortaucipir: T=6.34, p <0.001), except for NFL (MK‐6240: T=1.35, p = 0.18; Flortaucipir: T=1.14, p = 0.25)(Figure 2). Representative A and tau biomarker cases (Figure 3A), along with discordant cases classified as T+ by only one tracer (Figure 3B), are illustrated. Conclusion Our preliminary analysis revealed a higher prevalence of A‐/T+ cases with MK‐6240 than Flortaucipir, low concordance between tracers and consistently lower biomarker levels in A‐/T+ compared to A+/T+. Larger studies and longitudinal analyses are necessary to ascertain the pathological trajectories of A‐/T+ individuals with varying tau biomarker profiles.
Head‐to‐Head evaluation of plasma
p
‐tau217 associations with MK6240, Flortaucipir, PI2620, and RO948 tau PET tracers
Abstract Background Tau phosphorylation and aggregation are hallmark features of Alzheimer's disease pathology(AD). Previous studies have shown that plasma phosphorylated tau( p ‐tau) at threonine 217 can detect AD‐related tau tangle pathology. However, the head‐to‐head association between p ‐tau217 and different tau PET tracers remains unexplored. Here, we conducted a head‐to‐head comparison of the association between plasma p ‐tau217 and four distinct tau PET tracers[MK6240, Flortaucipir(FTP), PI2620, RO948]. Method We studied 338 individuals across the AD continuum from the HEAD study[190 cognitively unimpaired elderly(CU), 109 with mild cognitive impairment(MCI), and 39 with dementia] with available FTP, MK6240, and plasma p ‐tau217 measured by ALZpath assay. A subset of 64 individuals(28 CU, 25 MCI, and 11 dementia) also had PI2620 and RO948, and p ‐tau217 measured by Lumipulse. The strength of the association was determined using t‐value maps from regression models testing the association between each tau PET tracer and plasma p ‐tau217, and the extent was measured by the percentage of significant voxels(t‐value>3.2). R‐square metric was used to determine how much of the variance in tau PET tracer estimates was explained by plasma p ‐tau217 concentrations. Associations between p ‐tau217 with tau PET were evaluated using the Spearman test. Result We found that in CU, both the extent and magnitude of the association with plasma p ‐tau217 were higher for MK6240 compared to FTP (Figure 1A‐D). Plasma p ‐tau217 explained a greater proportion of the variance in MK6240 than in FTP (Figure 1E‐F). In CI, the extent and magnitude of the association were similar for MK6240 and FTP. Additionally, plasma p ‐tau217 explained a similar proportion of the variance in MK6240 and FTP. Using the subset of individuals who had all tau tracers, MK6240 showed a slightly higher extent of association with p ‐tau217, followed by FTP, PI2620, and RO948 (Figure 2A‐B). The magnitude of association was stronger for MK6240, followed by PI2620, RO948, and FTP (Figure 2C‐D). Plasma p ‐tau217 explained a greater proportion of the variance in MK6240, followed by FTP, RO948, and PI2620 (Figure 2E‐F). We compared the associations between different p ‐tau217 assays, and both assays presented similar associations with all tau PET tracers (Figure 3). Conclusion In summary, our results indicate that the four tau PET tracers exhibit robust associations with plasma p ‐tau217 in similar topographical regions.
Desmoplastic Small Round Cell Tumor: Study of Cytomorphologic and Immunophenotypical Features in Seven Cases, One With Unusual Rhabdoid Morphology
ABSTRACT Introduction Desmoplastic small round cell tumor (DSRCT) is a rare malignant mesenchymal neoplasm of polyphenotypic differentiation, characterized by EWSR1‐WT1 gene fusion. Despite multimodality therapy, the tumor carries poor prognosis. We report cytomorphological, immunohistochemical (IHC) and molecular features of seven cases of DSRCT from four patients. Materials and Methods A retrospective review of cytology smears, biopsies and molecular features of cases diagnosed as DSRCT at Department of Pathology, Henry Ford Health System, and Indiana University, USA between 2016 and 2022 were performed. A total of seven cases of DSRCT from four patients were included in this study. The cytological findings were correlated with concurrent or subsequent biopsy findings. Results All patients were male, with age ranging from 21 to 29 years. Two patients had primary tumor in the abdomen, one in the retroperitoneum, and one in the inguinal region. The tumors measured from 7.5 to 17 cm in size. Six out of seven cases showed typical hypercellular smears of small round cells with inconspicuous nucleoli, scant cytoplasm, and rare nuclear molding. The cytomorphology in Case no. 1 was unusual, showing discohesive pleomorphic tumor cells with large irregular nuclei, prominent nucleoli, occasional binucleation, and frequent mitotic activity. A subset of tumor cells demonstrated rhabdoid features. The tumor cells were positive for keratins (dot‐like), desmin, WT‐1, and CD15. In Case no. 4, the immunohistochemistry for desmin and WT‐1 was unusually negative reflecting the variability of the staining pattern. Three cases were positive for EWSR1 rearrangement by fluorescence in situ hybridization (FISH) and one positive for EWSR1‐WTI gene fusion by reverse transcriptase‐polymerase chain reaction (RT‐PCR). All seven cases had concurrent/subsequent surgical pathology diagnosis consistent with DSRCT. Conclusion Cytologic diagnosis for DSRCT is challenging but can be achieved with appropriate cytomorphology, IHC profiles, molecular studies, and demographic information. Rare rhabdoid differentiation can occur in DSRCT and can be present in effusion cytology.
Evaluation discrepancy between [
18
F]MK‐6240 and [
18
F]AV‐1451 tau‐PET using tau‐PET overlap index
Abstract Background The overlap index (OI), previously introduced by Lee et al. (2022), has proven to be a reliable method for detecting tau accumulation via tau‐PET imaging with flortaucipir ([ 18 F]AV‐1451). This technique identifies voxel‐wise increases in standardized uptake value ratio (SUVr) across serial scans. However, the relationship between tau‐PET measurements obtained with [ 18 F]MK‐6240 and [ 18 F]AV‐1451 using the OI remains unclear. This study aims to investigate the relationship between [ 18 F]MK‐6240 and [ 18 F]AV‐1451 tau‐PET using the tau‐PET OI. Method The study included 27 participants from the HEAD project, all of whom underwent two serial tau‐PET scans (each [ 18 F]MK‐6240 and [ 18 F]AV‐1451) along with 3T T1‐weighted MRI, acquired within an average interval of 18 months. SUVr maps for each tau‐PET tracer were normalized to the cerebellar crus grey matter, and MR images were co‐registered to the MCALT T1 template. Tau‐PET images were spatially resampled to the template space, and OI was computed within a predefined META‐ROI using an intensity threshold of 1.3 and a cutoff of 0.5. Clusters containing fewer than 20 contiguous voxels were excluded from analysis. The META‐ROI SUVr was calculated as the average SUVr across the selected region's SUVr. Additionally, a visual comparison was performed to assess the spatial overlap of OI‐identified voxels between the two tau‐PET tracers. Result OI values within the META‐ROI exhibited a broad distribution between [ 18 F]MK‐6240 and [ 18 F]AV‐1451 tau‐PET, particularly in cognitively unimpaired (CU) and younger individuals (Figure 1A). Unlike the OI distribution, the relationship between META‐ROI SUVr values of both tracers followed an exponential trend (Figure 1B). Visual inspection revealed that OI‐detected voxels in [ 18 F]MK‐6240 tau‐PET were frequently localized to the meninges, an established site of off‐target binding, which was not observed in [ 18 F]AV‐1451 tau‐PET (Figure 2). Conclusion The association between [ 18 F]MK‐6240 and [ 18 F]AV‐1451 tau‐PET, as assessed using the OI, exhibited considerable variability in CU and younger participants. Additionally, the presence of overlapping voxels in the meninges in [ 18 F]MK‐6240 tau‐PET highlights the need to account for and potentially exclude off‐target binding effects in these populations. The influence of meningeal signal and other off‐target binding on the OI in the temporal META‐ROI needs to be further evaluated.
COMPREHENSIVE GENETIC INVESTIGATION REVEALS HETEROGENEOUS PATHWAYS TO OBSTRUCTIVE SLEEP APNEA
ABSTRACT Obstructive sleep apnea (OSA) is a common, heritable disorder with diverse clinical presentations and etiologies. We conducted a genome-wide association meta-analysis of 492,107 individuals, including 46,028 OSA cases, identifying 14 genome-wide significant loci, eight of which are novel. Analyses adjusting for body mass index (BMI) revealed three loci independent of obesity, implicating alternative biological pathways contributing to disease. Integrative functional analyses, including chromatin interaction mapping, fine-mapping, and eQTL colocalization, prioritized candidate effector genes. Notably, implicated genes in chondrocytes were associated with craniofacial morphology in both mouse and human multivariate genotype-phenotype mapping, supporting a role for craniofacial structure in OSA risk. These findings highlight key genetic pathways (obesity-related, neurological, and craniofacial) underlying the development of OSA, offering new insights into its complex etiology.