How to deal with measures of association: a short guide for the clinician

Sex-Related Differences in Mortality, Delayed Cerebral Ischemia, and Functional Outcomes in Patients with Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

Background/Objective: Sex-related differences among patients with aneurysmal subarachnoid hemorrhage (aSAH) and their potential clinical implications have been insufficiently investigated. To address this knowledge gap, we conduct a comprehensive systematic review and meta-analysis. Methods: Sex-specific differences in patients with aSAH, including mortality, delayed cerebral ischemia (DCI), and functional outcomes were assessed. The functional outcome was dichotomized into favorable or unfavorable based on the modified Rankin Scale (mRS), Glasgow Outcome Scale (GOS), and Glasgow Outcome Scale Extended (GOSE). Results: Overall, 2823 studies were identified in EMBASE, MEDLINE, PubMed, and by manual search on 14 February 2024. After an initial assessment, 74 studies were included in the meta-analysis. In the analysis of mortality, including 18,534 aSAH patients, no statistically significant differences could be detected (risk ratio (RR) 0.99; 95% CI, 0.90-1.09; p = 0.91). In contrast, the risk analysis for DCI, including 23,864 aSAH patients, showed an 11% relative risk reduction in DCI in males versus females (RR, 0.89; 95% CI, 0.81-0.97; p = 0.01). The functional outcome analysis (favorable vs. unfavorable), including 7739 aSAH patients, showed a tendency towards better functional outcomes in men than women; however, this did not reach statistical significance (RR, 1.02; 95% CI, 0.98-1.07; p = 0.34). Conclusions: In conclusion, the available data suggest that sex/gender may play a significant role in the risk of DCI in patients with aSAH, emphasizing the need for sex-specific management strategies.

Sodium-glucose co-transporter-2 inhibitors and the risk of venous thromboembolism: A nationwide population-based study and meta-analysis

AIMS

Sodium-glucose cotransporter-2 inhibitors (SGLT-2i) have off-target effects on haemoconcentration and anti-inflammation. The impact of SGLT-2i on the risk of venous thromboembolism (VTE) in patients with diabetes mellitus (DM) remains unclear. This study aimed to evaluate the risk of newly diagnosed VTE in patients with DM using SGLT-2i in comparison to dipeptidyl peptidase-4 inhibitors (DPP-4i) or glucagon-like peptide-1 receptor agonists (GLP-1RA).

MATERIALS AND METHODS

In this nationwide retrospective cohort study, we used data from Taiwan's National Health Insurance Research Database. Patients with diabetes aged 20 years or older who received SGLT-2i, DPP-4i, or GLP-1RA between 1 May 2016, and 31 December 2020, were included. The risks of VTE in SGLT-2i users were compared with those of DPP-4i and GLP-1RA users. A Cox regression model with stabilised inverse probability of treatment weighting was used to calculate hazard ratio (HR) for VTE risk. Additionally, a meta-analysis of relevant articles published before 23 May 2023, was conducted.

RESULTS

Data from 136,530 SGLT-2i, 598,280 DPP-4i, and 5760 GLP-1RA users were analysed. SGLT-2i use was associated with a lower risk of VTE than DPP-4i (HR, 0.70; 95% CI, 0.59-0.84; p < 0·001), but not with GLP-1RA (HR, 1.39; 95% CI, 0.32-5.94; p = 0.66). Our meta-analysis further supported these findings (SGLT-2i vs. DPP-4i: HR, 0.71; 95% CI, 0.62-0.82; p < 0·001; SGLT-2i vs. GLP-1RA: HR, 0.91; 95% CI, 0.73-1.15; p = 0.43), suggesting the robustness of our retrospective analysis.

CONCLUSIONS

In patients with DM, SGLT-2i was associated with a lower risk of VTE compared to DPP-4i, but not GLP-1RA.

Comparison of different risk scores for Parkinson disease in a population-based 10-year study

BACKGROUND AND PURPOSE

Different algorithms aiming to identify individuals at risk of Parkinson disease (PD) have been proposed. Comparative studies of these scores and their recent updates in the general elder population are needed.

METHODS

We have previously applied the "basic" PREDICT-PD algorithm, designed for remote screening, and the original and updated Movement Disorder Society (MDS) criteria for prodromal PD to the longitudinal population-based Bruneck study cohort. We have now additionally employed the "enhanced" PREDICT-PD algorithm (which includes motor assessment, olfaction, probable rapid eye movement sleep behaviour disorder status, pesticide exposure, and diabetes as additional factors). Risk scores were calculated based on comprehensive baseline assessments (2005) in 574 subjects aged 55-94 years (290 females), and cases of incident PD were identified at 5-year (n = 11) and 10-year follow-up (n = 9). We analysed the association of the different log-transformed risk scores with incident PD at follow-up (calculated per 1-SD unit change).

RESULTS

The enhanced PREDICT-PD algorithm was associated with incident PD over 10-years of follow-up, yielding higher odds for incident PD (odds ratio [OR] = 4.61, 95% confidence interval [CI] = 2.68-7.93, p < 0.001) compared with the basic PREDICT-PD score (OR = 2.38, 95% CI = 1.49-3.79, p < 0.001). The updated MDS prodromal criteria yielded a numerically higher OR of 7.13 (95% CI = 3.49-14.54, p < 0.001) in comparison with the original criteria as well as the enhanced PREDICT-PD algorithm, with overlapping 95% CIs.

CONCLUSIONS

The enhanced PREDICT-PD algorithm was significantly associated with incident PD. The consistent performance of both the enhanced PREDICT-PD algorithm and the updated MDS prodromal criteria compared to their original versions supports their use in PD risk screening.

Risk of Subsequent Dementia or Alzheimer Disease Among Patients With Age-Related Macular Degeneration: A Systematic Review and Meta-analysis

PURPOSE

Alzheimer disease (AD), a common form of dementia, shares several clinical and pathologic features with age-related macular degeneration (AMD). Epidemiologic reports on the association of AMD with subsequent dementia or AD are inconsistent.

DESIGN

Systematic review and meta-analysis.

METHODS

The Meta-analysis of Observational Studies in Epidemiology reporting guidelines were applied. The Newcastle-Ottawa Scale was used to evaluate the risk of bias in the included cohort studies that examined the association of AMD with subsequent dementia or AD. We estimated the pooled hazard ratios (HRs) of dementia or AD using random effects model meta-analysis and subgroup analysis on different follow-up periods, AMD subtype, gender, age, study design, and methods to ascertain dementia or AD.

RESULTS

A total of 8 223 581 participants were included in 8 studies published during 2000-2021. The meta-analysis showed that AMD was significantly associated with subsequent dementia (pooled HR 1.22, 95% CI 1.01-1.47) or AD (pooled HR 1.21, 95% CI 1.03-1.43). Our secondary analysis revealed that the association was more noticeable in dry AMD than wet AMD.

CONCLUSIONS

Patients with AMD have higher risks of developing dementia or AD, and therefore identifying related comorbidities and retinal biomarkers is much warranted for older adults with AMD in ophthalmologic practice.

Risk and protective factors for self-harm and suicide in children and adolescents: a systematic review and meta-analysis protocol

INTRODUCTION

Self-harm and suicide are major public health concerns among children and adolescents. Many risk and protective factors for suicide and self-harm have been identified and reported in the literature. However, the capacity of these identified risk and protective factors to guide assessment and management is limited due to their great number. This protocol describes an ongoing systematic review and meta-analysis which aims to examine longitudinal studies of risk factors for self-harm and suicide in children and adolescents, to provide a comparison of the strengths of association of the various risk factors for self-harm and suicide and to shed light on those that require further investigation.

METHODS AND ANALYSIS

We perform a systematic search of the literature using the databases EMBASE, PsycINFO, Medline, CINAHL and HMIC from inception up to 28 October 2020, and the search will be updated before the systematic review publication. Additionally, we will contact experts in the field, including principal investigators whose peer-reviewed publications are included in our systematic review as well as investigators from our extensive research network, and we will search the reference lists of relevant reviews to retrieve any articles that were not identified in our search. We will extract relevant data and present a narrative synthesis and combine the results in meta-analyses where there are sufficient data. We will assess the risk of bias for each study using the Newcastle-Ottawa Scale and present a summary of the quantity and the quality of the evidence for each risk or protective factor.

ETHICS AND DISSEMINATION

Ethical approval will not be sought as this is a systematic review of the literature. Results will be published in mental health journals and presented at conferences focused on suicide prevention.

PROSPERO REGISTRATION NUMBER

CRD42021228212.

Preprocedural muscle strength and physical performance and the association with functional decline or mortality in frail older patients after transcatheter aortic valve implementation: a systematic review and meta-analysis

BACKGROUND

A significant number of older patients planned for transcatheter aortic valve implantation (TAVI) experience a decline in physical functioning and death, despite a successful procedure.

OBJECTIVE

To systematically review the literature on the association of preprocedural muscle strength and physical performance with functional decline or long-term mortality after TAVI.

METHODS

We followed the PRISMA guidelines and pre-registered this review at PROSPERO (CRD42020208032). A systematic search was conducted in MEDLINE and EMBASE from inception to 10 December 2021. Studies reporting on the association of preprocedural muscle strength or physical performance with functional decline or long-term (>6 months) mortality after the TAVI procedure were included. For outcomes reported by three or more studies, a meta-analysis was performed.

RESULTS

In total, two studies reporting on functional decline and 29 studies reporting on mortality were included. The association with functional decline was inconclusive. For mortality, meta-analysis showed that low handgrip strength (hazard ratio (HR) 1.80 [95% confidence interval (CI): 1.22-2.63]), lower distance on the 6-minute walk test (HR 1.15 [95% CI: 1.09-1.21] per 50 m decrease), low performance on the timed up and go test (>20 s) (HR 2.77 [95% CI: 1.79-4.30]) and slow gait speed (<0.83 m/s) (HR 2.24 [95% CI: 1.32-3.81]) were associated with higher long-term mortality.

CONCLUSIONS

Low muscle strength and physical performance are associated with higher mortality after TAVI, while the association with functional decline stays inconclusive. Future research should focus on interventions to increase muscle strength and physical performance in older cardiac patients.

Risk of incident diabetes post-COVID-19: A systematic review and meta-analysis

It remains undetermined whether burden of diabetes newly detected during acute COVID-19 persist in post-acute COVID phase. This meta-analysis was conducted to summarize the available literature and provide a pooled estimate of the risk of developing incident diabetes following hospital discharge or at least 28 days after the COVID-19 diagnosis compared to matched controls or severity matched influenza/ non-COVID-19 acute upper respiratory tract infections (AURI). Pooled analysis of 5787,027 subjects from four observational studies showed 59 % higher risk of developing incident diabetes in post-acute COVID-19 phase versus healthy controls (HR:1.59; 95 % CI:1.40-1.81, p < 0.001, I²=94 %, random-effects model). The high degree of heterogeneity in pooled estimate can be attributed to difference in demographic characteristics, hospitalization rates or disease severity between study subjects. Pooling data from three studies, higher risk of incident diabetes was also observed following COVID-19 versus severity matched non-COVID-19 respiratory tract infections (moderate-severe/hospitalized cases, HR 1.52; 95 % CI: 1.36-1.70, p < 0.01, I²=0 %, fixed-effects model; mild cases, HR 1.22; 95 % CI: 1.14-1.31, p < 0.001; I²=0 %, fixed-effects model). Majority of studies had median follow-up period of around 4 months. In view of several limitations due to retrospective design of these studies, prospective studies with long term follow-up are warranted.

Peri-Operative Outcomes of Carotid Endarterectomy are Not Improved on Dual Antiplatelet Therapy vs. Aspirin Monotherapy: A Systematic Review and Meta-Analysis

OBJECTIVE

A systematic review and meta-analysis of the peri-operative outcomes of carotid endarterectomy (CEA) on dual antiplatelet therapy (DAPT) vs. aspirin monotherapy was carried out, to determine optimal peri-operative management with these antiplatelet agents.

DATA SOURCES

The Web of Science, Pubmed, and Embase databases were searched from inception to July 2021. The corresponding authors of excluded articles were contacted to obtain additional data for possible inclusion.

REVIEW METHODS

The main outcomes included ischaemic complications (stroke, transient ischaemic attack [TIA], and transcranial Doppler [TCD] measured micro-emboli), haemorrhagic complications (haemorrhagic stroke, neck haematoma, and re-operation for bleeding), and composite outcomes. Pooled estimates using odds ratios (ORs) were combined using a random or fixed effects model based on the results of the chi square test and calculation of I².

RESULTS

In total, 47 411 patients were included in 11 studies, with 14 345 (30.2%) receiving DAPT and 33 066 (69.7%) receiving aspirin only. There was no significant difference in the rates of peri-operative stroke (OR 0.87, 95% confidence interval [CI] 0.72 - 1.05) and TIA (OR 0.78, 95% CI 0.52 - 1.17) despite a significant reduction in TCD measured micro-emboli (OR 0.19, 95% CI 0.10 - 0.35) in the DAPT compared with the aspirin monotherapy group. Subgroup analysis did not reveal any significant difference in ischaemic stroke risk between patients with asymptomatic and symptomatic carotid artery stenosis. DAPT was associated with an increased risk of neck haematoma (OR 2.79, 95% CI 1.87 - 4.18) and re-operation for bleeding (OR 1.98, 95% CI 1.77 - 2.23) vs. aspirin. Haemorrhagic stroke was an under reported outcome in the literature.

CONCLUSION

This meta-analysis found that CEA while on DAPT increased the risk of haemorrhagic complications, with similar rates of ischaemic complications, vs. aspirin monotherapy. This suggests that the risks of performing CEA on DAPT outweigh the benefits, even in patients with symptomatic carotid stenosis. The overall quality of studies was low, and improved reporting of CEA outcomes in the literature is necessary.

Effects of early medication treatment and metformin use for cancer prevention in diabetes patients: a nationwide sample cohort study using extended landmark-time analysis

OBJECTIVES

This study investigated the effectiveness of early medication treatment and metformin use for cancer prevention in type 2 diabetes patients.

METHODS

Population-based cohort data were used from the Korean National Health Insurance Service-National Sample Cohort database (KNHIS-NSC) for 2002–2013. Patient-specific medication prescription status was defined by the landmark time (LMT; a fixed time after cohort entry), considering both pre- and post-LMT prescriptions to control methodological biases in observational research. The LMT was set to 2 years. Logistic regression analysis with multivariable adjustment was conducted to analyze cancer incidence by patient-specific medication prescription status.

RESULTS

Only 33.4% of the subjects were prescribed medication early (before the LMT) with compliance. Cancer incidence in individuals with early prescription and compliance was 25% lower (odds ratio [OR], 0.75; 95% confidence interval [CI], 0.67 to 0.84) than in those without. As early-prescribed medications, metformin monotherapy and metformin combination therapy were associated with 34% (OR, 0.66; 95% CI, 0.51 to 0.83) and 25% (OR, 0.75; 95% CI, 0.64 to 0.88) lower cancer risk than non-use, respectively. Patients who were prescribed late (post-LMT) but did not comply with the prescription had a 24% (OR, 1.24; 95% CI, 0.97 to 1.58) higher cancer incidence than non-users. Among patients who started monotherapy early without changes throughout the entire follow-up period, those who started on metformin had a 37% (OR, 0.63; 95% CI, 0.41 to 0.99) lower risk of cancer than non-metformin users.

CONCLUSIONS

Doctors must prescribe antidiabetic medication early, and patient compliance is required, regardless of the prescription time, to prevent cancer. Metformin monotherapy or combination therapy is recommended as an early prescription.

The association between surgical fixation of hip fractures within 24 hours and mortality : a systematic review and meta-analysis

AIMS

The aim of this study was to assess the effect of time to surgical intervention from admission on mortality and morbidity for patients with hip fractures.

METHODS

MEDLINE and Embase were searched from inception to June 2020. Reference lists were manually assessed to identify additional papers. Primary comparative research studies that recruited patients aged over 60 years, with non-pathological primary proximal femoral fractures that were treated surgically, were included. Studies that did not include a group operated on within 24 hours or which reported time to surgery in calendar days were excluded. Two investigators extracted data on study characteristics, methods, and outcomes. The pre-defined primary outcome was 30-day mortality. Secondary outcomes were complications and mortality at other time points. Relative risks (RRs) with 95% confidence intervals (CIs) were aggregated and were grouped by study-level characteristics.

RESULTS

This review included 46 studies (January 1991 to June 2020), comprising 521,857 hip fractures with 64,047 postoperative deaths. No randomized controlled trials were eligible for inclusion. In a pooled analysis of 15 studies, RR of mortality at 30 days comparing time to surgery < 24 hours with > 24 hours was 0.86 (95% CI 0.82 to 0.91; I 2 = 69%; 95% CI 50% to 81%; p-value for heterogeneity < 0.001). The association was stronger in observational studies that did not adjust for confounders than in those that adjusted for multiple covariates. In a pooled analysis of six studies, the RR of mortality at 30 days comparing time to surgery < 24 hours with 24 to 36 hours was 0.87 (95% CI 0.81 to 0.93; I 2 = 65%; 95% CI 16% to 85%; p-value for heterogeneity = 0.014).

CONCLUSION

This meta-analysis indicates reduced mortality for patients operated within 24 hours compared with those operated on beyond 24 hours or within 24 to 36 hours. Where resources allow and there is no specific reversible contraindication to early surgery, we recommend that hip fractures should be surgically treated within 24 hours. Cite this article: Bone Joint J 2021;103-B(7):1176-1186.

Novel statistical approaches to identify risk factors for soil-transmitted helminth infection in Timor-Leste

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We compared logistic regression, recursive partitioning and Bayesian networks to identify risk factors for STH infection.

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Logistic regression identified fewest variables associated with STH infections compared with the two alternative methods.

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Recursive partitioning identified more demographic and WASH variables, and Bayesian networks more environmental variables.

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Model performance was similar across all three statistical techniques.

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Recursive partitioning can identify at-risk population subgroups, while Bayesian networks can run real-time scenarios.

Soil-transmitted helminths (STHs) are parasitic intestinal worms that infect almost a fifth of the global population. Sustainable control of STHs requires understanding the complex interaction of factors contributing to transmission. Identifying risk factors has mainly relied on logistic regression models where the underlying assumption of independence between variables is not always satisfied. Previously demonstrated risk factors including water, sanitation and hygiene (WASH) access and behaviours, and socioeconomic status are intrinsically linked. Similarly, environmental factors including climate, soil and land attributes are often strongly correlated. Alternative methods such as recursive partitioning and Bayesian networks can handle correlated variables, but there are no published studies comparing these methods with logistic regression in the context of STH risk factor analysis. Baseline cross-sectional data from school-aged children in the (S)WASH-D for Worms study were used to compare risk factors identified from modelling the same data using three different statistical techniques. Outcomes of interest were infection with Ascaris spp. and any hookworm species (Necator americanus, Ancylostoma duodenale, and Ancylostoma ceylanicum). Mixed-effects logistic regression identified the fewest risk factors. Recursive partitioning identified the most WASH and demographic risk factors, while Bayesian networks identified the most environmental risk factors. Recursive partitioning produced classification trees that visualised potentially at-risk population sub-groups. Bayesian networks helped visualise relationships between variables and enabled interactive modelling of outcomes based on different scenarios for the predictor variables of interest. Model performance was similar across all techniques. Risk factors identified across all techniques were vegetation for Ascaris spp., and cleaning oneself with water after defecating for hookworm. This study adds to the limited body of evidence exploring alternative data modelling approaches in identifying risk factors for STH infections. Our findings suggest these approaches can provide novel insights for more robust interpretation.

Statistical fundamentals on cancer research for clinicians: Working with your statisticians

PURPOSE

To facilitate understanding statistical principles and methods for clinicians involved in cancer research.

METHODS

An overview of study design is provided on cancer research for both observational and clinical trials addressing study objectives and endpoints, superiority tests, non-inferiority and equivalence design, and sample size calculation. The principles of statistical models and tests including contemporary standard methods of analysis and evaluation are discussed. Finally, some statistical pitfalls frequently evident in clinical and translational studies in cancer are discussed.

RESULTS

We emphasize the practical aspects of study design (superiority vs non-inferiority vs equivalence study) and assumptions underpinning power calculations and sample size estimation. The differences between relative risk, odds ratio, and hazard ratio, understanding outcome endpoints, purposes of interim analysis, and statistical modeling to minimize confounding effects and bias are also discussed.

CONCLUSION

Proper design and correctly constructed statistical models are critical for the success of cancer research studies. Most statistical inaccuracies can be minimized by following essential statistical principles and guidelines to improve quality in research studies.

Handgrip strength-A risk indicator for type 2 diabetes: Systematic review and meta-analysis of observational cohort studies

AIMS

Evolving debate suggests that handgrip strength (HGS), a measure of muscular strength, might be associated with the risk of type 2 diabetes (T2D); however, the evidence is conflicting. Using a systematic review and meta-analysis of published observational cohort studies in general populations, we aimed to assess the association of HGS with the future risk of T2D.

METHODS

Relevant studies were sought from inception until April 2020 in MEDLINE, Embase, Web of Science, and manual search of relevant articles. Transformed or extracted relative risks (RRs) with 95% confidence intervals (CIs) comparing the top vs bottom thirds of HGS levels were pooled using random effects meta-analysis.

RESULTS

A total of 10 unique observational cohort studies comprising of 177 826 participants and >5167 T2D cases were eligible. The pooled multivariable RR (95% CI) for T2D comparing the top vs bottom thirds of HGS levels was 0.73 (0.63-0.84). This association was consistent across several relevant subgroups except for evidence of effect modification by sample size (P value for meta-regression <.001): evidence of an association in smaller studies (<250 events) 0.50 (0.40-0.63), with no significant association in bigger studies (≥250 events) 0.87 (0.73-1.05). There was no evidence of small study effects using formal tests such as funnel plots and Egger's regression symmetry test.

CONCLUSION

Pooled analysis of observational cohort studies suggests that HGS may be a risk indicator for T2D in the general population. The role of utilizing HGS measurements in T2D prevention strategies warrants further investigation.

Application of a Simple Parkinson's Disease Risk Score in a Longitudinal Population-Based Cohort

BACKGROUND

Identifying individuals at risk of developing Parkinson's disease (PD) is critical to define target populations for future neuroprotective trials.

OBJECTIVE

The objective of this study was to apply the PREDICT-PD algorithm of risk indicators for PD in a prospective community-based study (the Bruneck study), representative of the general elderly population.

METHODS

PREDICT-PD risk scores were calculated based on risk factor assessments obtained at baseline (2005, n = 574 participants). Cases of incident PD were identified at 5-year and 10-year follow-ups. Participants with PD or secondary parkinsonism at baseline were excluded (n = 35). We analyzed the association of log-transformed risk scores with the presence of well-established markers as surrogates for PD risk at baseline and with incident PD at follow-up.

RESULTS

A total of 20 participants with incident PD were identified during follow-up (11 after 5 years and 9 after 10 years). Baseline PREDICT-PD risk scores were associated with incident PD with odds ratios of 2.09 (95% confidence interval, 1.35-3.25; P = 0.001) after 5 years and of 1.95 (1.36-2.79; P < 0.001) after 10 years of follow-up per doubling of risk scores. In addition, higher PREDICT-PD scores were significantly correlated with established PD risk markers (olfactory dysfunction, signs of rapid eye movement sleep behavior disorder and motor deficits) and significantly associated with higher probability for prodromal PD according to the Movement Disorder Society research criteria at baseline.

CONCLUSIONS

The PREDICT-PD score was associated with an increased risk for incident PD in our sample and may represent a useful first screening step in future algorithms aiming to identify cases of prodromal PD. © 2020 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.