Category: Statistics

Eur J Psychotraumatol. 2026 Dec;17(1):2652128. doi: 10.1080/20008066.2026.2652128. Epub 2026 May 26.

ABSTRACT

Introduction: Prolonged Grief Disorder (PGD) was newly included in the 11th edition of the International Classification of Diseases (ICD-11) and the text revision of the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR). There is a need to increase our understanding of the prevalence, nature, and risk factors of this condition. Research in this area can be advanced by pooling existing datasets.Objective: The MARBLES (Multi-region Archive of Research data on Bereavement and Loss from Empirical Studies) project was initiated to create a consortium of researchers conducting studies on PGD. Its goal is to harmonize and combine data from separate studies into a unified, individual participant data-archive, boosting bereavement research.Methods: To date, data from 16,666 bereaved individuals have been compiled from 32 datasets across nine countries. All datasets include data on PGD symptoms and sociodemographic and loss characteristics; most also include data on emotion regulation and concurrent symptoms. For preliminary analyses presented in this paper, data on sociodemographic and loss-related characteristics and on PGD, posttraumatic stress, and depression symptoms were harmonized.Results: Regarding the preliminary analyses, participants’ mean age was in their mid-40s, about 70% of the participants were female, one in four participants had lost a partner, and one in four participants experienced an unnatural loss. Analyses (with multiple imputation) indicated that 18.3% met criteria for probable PGD (ICD-11).Conclusion: The MARBLES archive demonstrates that it is feasible to build a FAIR archive of PGD symptom data. Although the archive can already be used to study the prevalence, pathogenesis, and predictors of PGD symptoms and associated emotional problems, it is intended as an evolving resource. Its potential will expand as additional datasets are added and use of the archive grows. Future extensions should prioritize the inclusion of underrepresented groups (e.g. migrants) and currently missing social, cognitive, and neurobiological variables.

PMID:42186902 | DOI:10.1080/20008066.2026.2652128

Sci Prog. 2026 Apr-Jun;109(2):368504261456424. doi: 10.1177/00368504261456424. Epub 2026 May 26.

ABSTRACT

ObjectiveAlthough endoscope-assisted evacuation for chronic subdural hematoma (cSDH) may reduce recurrence rates, its adoption has been limited by a procedural learning curve that may affect operative efficiency and clinical outcomes. This study compared conventional burr-hole craniostomy with endoscope-assisted evacuation for symptomatic cSDH and evaluated the challenges of institutional implementation.MethodsWe retrospectively reviewed patients with symptomatic cSDH treated between 2023 and 2025. Patients in the treatment group underwent endoscopic-assisted hematoma evacuation, while those in the control group received conventional burr-hole craniostomy. Continuous variables were compared using Student’s t-test or Mann-Whitney U test, and categorical variables were analyzed using Fisher’s exact or Chi-square tests. Multivariable logistic regression was performed to identify independent predictors of outcomes, with results reported as adjusted odds ratios (aOR) and 95% confidence intervals (CI). Statistical significance was defined as a two-tailed p < 0.05. All analyses were conducted using R software.ResultsA total of 110 patients were included (treatment group, n = 60; control group, n = 50). Patients in the treatment group were older (p = 0.006), whereas baseline characteristics and clinical presentations were otherwise comparable between groups. Operative time was longer in the treatment group (123.8 ± 45.2 vs. 104.3 ± 42.0 minutes, p = 0.02). No significant differences were observed in postoperative Glasgow Coma Scale scores, modified Rankin Scale scores, complication or recurrence rates, length of hospital stay, or functional recovery. Operative time decreased with increasing surgeon experience in unilateral endoscopic cases, indicating the presence of a learning curve.ConclusionEndoscope-assisted evacuation is a safe and effective alternative to conventional burr-hole craniostomy for cSDH, without increased complications or compromised clinical outcomes during institutional adoption.

PMID:42186899 | DOI:10.1177/00368504261456424

Brain. 2026 May 26:awag187. doi: 10.1093/brain/awag187. Online ahead of print.

ABSTRACT

SORL1, the gene encoding the SORLA protein, has arisen as a potential therapeutic target for Alzheimer’s disease (AD). Studies suggest that restoring SORLA function or its trafficking pathways, particularly the SORLA-retromer recycling system, may offer a promising strategy to slow or halt AD progression. While both rare and common SORL1 variants have been associated with increased AD risk, recent evidence suggests a potential involvement of SORL1 in other neurodegenerative conditions. This study assessed the contribution of SORL1 genetic variation to the risk of AD, related dementias (RD), and Parkinson’s disease (PD) using data from six large-scale biobanks, comprising 15,043 AD, 9,943 RD, and 42,763 PD cases, along with 111,969 controls across 11 ancestries. We identified 53 potentially disease-related SORL1 variants (CADD score > 20, MAC ≥ 2, annotated as protein-altering or splicing, and with the mutated allele present only in cases), including 41 novel and 12 previously reported variants. Three were found across multiple ancestries. Overall, 13 variants were found in AD-related cohorts, 5 in RD cohorts, and 35 in PD cohorts. Association analysis identified 10 nominally significant variants associated with AD and 5 with PD. The replication of multiple SORL1 variants across neurodegenerative diseases and ancestrally diverse populations underscores its potential broad genetic contribution to neurodegeneration and reinforces its relevance across distinct clinical phenotypes. Burden analysis identified a nominal association of SORL1 variants in PD in the South Asian population (P = 0.048). A family-based analysis identified a rare predicted-damaging variant in two East Asian families (11:121478242:G:A, p.R176Q) and two variants in two families of European ancestry (11:121514222:A:C, p.N371T; 11:121545392:G:A, p.V672M) that show some evidence of segregation in PD families. Although these variants were slightly more frequent in unrelated PD cases vs. controls, none of them showed statistically significant enrichment in PD, likely due to their very low frequency. Overall, our results extend the understanding of SORL1 beyond AD, suggesting a broader role in neurodegeneration and emphasizing the need for diverse population studies when evaluating genetic risk.

PMID:42186854 | DOI:10.1093/brain/awag187

Stat Med. 2026 Jun;45(13-14):e70612. doi: 10.1002/sim.70612.

ABSTRACT

The majority of response-adaptive randomization (RAR) designs in the literature rely on efficacy data to guide dynamic patient allocation. However, their applicability becomes limited in settings where efficacy outcomes, such as survival, are observed with a random delay. To address this limitation, we introduce SAFER, a novel RAR design that leverages early-emerging safety data to inform treatment allocation decisions, particularly in oncology trials. The design is broadly applicable to contexts where prioritizing the arm with superior safety is desirable. This is especially relevant in noninferiority trials, to demonstrate that an experimental treatment is not inferior to the standard of care, while potentially offering improved tolerability. In such trials, an unavoidable trade-off arises: maintaining statistical efficiency for the efficacy hypothesis while integrating safety-driven adaptations through RAR. The SAFER design addresses this trade-off by dynamically adjusting the allocation proportion based on the observed association between safety and efficacy endpoints. We illustrate the performance of SAFER through a simulation study inspired by the CAPP-IT Phase III oncology trial. Results show that SAFER preserves statistical power, reduces the adverse event rate, and offers flexible adaptation speed depending on the temporal alignment of the endpoints.

PMID:42186850 | DOI:10.1002/sim.70612

J Sleep Res. 2026 May 26:e70356. doi: 10.1111/jsr.70356. Online ahead of print.

ABSTRACT

How phenotypes are measured, especially when relying on subjective reports, is an impediment to the utility of genome-wide association studies (GWAS). This is a common problem in GWAS for sleep traits, as many sleep disturbances appear subjectively similar despite having distinct underlying pathophysiology. Phenotype refinement is, therefore, necessary to improve our understanding of complex trait biology. Here, we utilise expanded questionnaire data collected from ~180,000 participants in the UK Biobank to help further distinguish insomnia from restless legs syndrome (RLS) from subjective reports. We demonstrate prior GWAS efforts for insomnia likely mischaracterised participants using a single-question approach. Through statistical models, we examine two of the most significant GWAS signals for insomnia, namely at the MEIS1 and BTBD9 loci, finding their effects are largely or completely, driven by their effects on RLS. Collectively, our results underscore the necessity of improving phenotype classification and highlight the utility of newly released UK Biobank data for sleep research.

PMID:42186847 | DOI:10.1111/jsr.70356

Stat Med. 2026 Jun;45(13-14):e70586. doi: 10.1002/sim.70586.

ABSTRACT

There is a growing literature on estimating effects of treatment strategies based on the natural treatment that would have been received in the absence of intervention, often dubbed “modified treatment policies” (MTPs). MTPs are sometimes of interest because they are more realistic than interventions setting exposure to an ideal level for all members of a population. In the general time-varying setting, Richardson and Robins (2013) provided exchangeability conditions for nonparametric identification of MTP effects that could be deduced from single world intervention graphs (SWIGs). Díaz et al. (2023) provided multiply robust estimators under these identification assumptions that allow for machine learning nuisance regressions. In this paper, we fill a remaining gap by extending structural nested mean models (SNMMs) (Robins, 1994, 2004, Vansteelandt and Joffe, 2014) to MTP settings, which enables characterization of (time-varying) heterogeneity of MTP effects. We do this both under the exchangeability assumptions of Richardson and Robins (2013) and under parallel trends assumptions, which enables investigation of (time-varying heterogeneous) MTP effects in the presence of some unobserved confounding.

PMID:42186838 | DOI:10.1002/sim.70586

Healthc Policy. 2026 May;21(3):100-108. doi: 10.12927/hcpol.2026.27801.

ABSTRACT

The Ontario Wait Time Information System (WTIS) provides publicly accessible surgical wait time data. This study evaluated WTIS use among Ontario primary care physicians to understand how wait time information is interpreted and applied. We invited 1,306 physicians to complete an online survey. Of 151 respondents, 90.9% were unaware of the WTIS. However, 87.5% said hospital wait time data would influence referrals, and 95.1% preferred surgeon-specific wait times. In addition, 97.2% were willing to use a single-entry referral system. Increasing WTIS awareness and adding surgeon-level data may enhance referral practices.

PMID:42186837 | DOI:10.12927/hcpol.2026.27801

Healthc Policy. 2026 May;21(3):86-99. doi: 10.12927/hcpol.2026.27800.

ABSTRACT

BACKGROUND: Long wait times for elective surgery represent a persistent challenge in healthcare systems and for waiting patients, particularly in Canada. Delays to elective surgery impact patient well-being but may also disproportionately affect vulnerable populations. Despite high levels of immigration to Canada, research regarding immigrants’ access to elective surgical care remains scarce. This population-based study measures and compares wait times for common elective general surgeries for immigrants with non-immigrants in British Columbia (BC), Canada.

METHODS: All elective general surgery procedures performed in BC, Canada, between 2013 and 2021, were identified using hospital discharge summaries’ procedure codes. A longitudinal cohort was created by linking cohort members with immigration and physician billing data. Patients’ wait time was defined as the duration between the last general surgery visit and the surgery date. Wait times were compared between immigrants and non-immigrants, adjusting for patient- and system-level factors using multivariable regression.

RESULTS: Among 159,151 elective general surgeries, 14.3% were performed on immigrants. Immigrants experienced longer wait times on average compared with non-immigrants (83.7 vs 76.3 days), a difference that remained significant after adjustment (rate ratio [RR]: 1.03, 95% confidence interval [CI]: 1.01, 1.05). Differences were most pronounced for cholecystectomies; immigrants waited 15.4 days longer on average (unadjusted) than non-immigrants. Among immigrants, “visible minorities” waited longer compared with immigrants from European/English-speaking countries (RR: 1.06, 95% CI: 1.03, 1.10).

CONCLUSION: This study highlighted that immigrants tended to wait longer for elective surgery in this study’s setting. Visible minorities experienced the longest waits. Despite sharing the same structures and processes of care in the setting’s publicly funded health system, barriers in healthcare delivery delayed access to elective surgical care for immigrants.

PMID:42186836 | DOI:10.12927/hcpol.2026.27800

Healthc Policy. 2026 May;21(3):36-42. doi: 10.12927/hcpol.2026.27772.

ABSTRACT

Canadian healthcare confronts persistent surgical capacity constraints driven by demographic pressures, economic limitations and inefficient resource utilization. Despite substantial resource requirements, operating rooms frequently remain underutilized due to misaligned policies and incentives. Introducing “collectable time” provides a foundation for comprehensive policy reform to resolve these inefficiencies. Addressing these inefficiencies through detailed, multi-level policy changes is critical to sustainably improving healthcare system productivity. Embedding collectable time metrics within institutional, provincial, federal and regulatory frameworks could increase surgical capacity without requiring additional staff or infrastructure.

PMID:42186829 | DOI:10.12927/hcpol.2026.27772

Disabil Rehabil Assist Technol. 2026 May 26:1-22. doi: 10.1080/17483107.2026.2677768. Online ahead of print.

ABSTRACT

PURPOSE: Article 20 of the UN Convention on the Rights of Persons with Disabilities obliges States Parties to facilitate access to assistive products, yet population-level data for the Gulf remain scarce. Guided by the WHO GATE framework and the rATA tool, this study estimated current assistive-product use and unmet need among Kuwaiti adults and identified their sociodemographic and functional correlates.

MATERIALS AND METHODS: A cross-sectional mixed-methods online survey using a locally adapted Arabic rATA was disseminated via convenience and snowball sampling through Kuwait University, the Public Authority for Persons with Disability, civil-society organisations, and social media. Quantitative data were analysed using descriptive statistics, χ² tests, Cronbach’s alpha, and multivariable logistic regression; six interviews were analysed thematically.

RESULTS: Of 652 respondents (84.4% female; 62.4% aged 18-28), 18.9% reported diagnosed disability and 69.0% reported Washington Group functional difficulty. Current use was 41.1%, clustering in vision (83.2% of users), cognition (64.6%), and communication (53.7%). Unmet need was 8.6%, most often attributed to cost (46.4%). Among users, 54.1% self-funded and 10.8% received government funding. Satisfaction was highest for environmental fit (M = 4.12) and lowest for repair (M = 3.59; α = 0.72). Disability (aOR 9.18, 95% CI 5.25-16.06) and functional difficulty (aOR 4.85, 3.04-7.73) were the dominant correlates.

CONCLUSIONS: In this non-probability sample, assistive-product use was driven by disability and functional difficulty rather than socioeconomic position, yet most users self-funded and cost dominated unmet need. Strengthening publicly funded procurement, follow-up services, and product coverage beyond vision aids would align Kuwait with WHO GATE and CRPD obligations-findings directly relevant to rehabilitation service planning.

PMID:42186824 | DOI:10.1080/17483107.2026.2677768