Marginal Risk Research Articles

Association analysis of FMR1 genetic variants and primary ovarian insufficiency in South Indian women with a novel approach of CGG repeats classification

Around 20–28% of FMR1gene CGG premutation (PM) carriers are at augmented risk towards an infertility related disorder, Fragile X-associated primary ovarian insufficiency (FXPOI). Except the effect of CGG repeats, reports are not available on the mechanism through which the cis-acting variations, namely, SNPs involved in POI susceptibility. Addressing the hypothesis that the FMR1 gene polymorphisms [CGG repeats, rs25731(T > A) and rs4949(A > G)] might increase their individual and combined impact in disease predisposition, we tested the genetic variants in 200 south Indian DNA samples consists of 100 patients and 100 healthy volunteers. We used gene scan method to score the CGG repeat length, and ARMS and RFLP methods to genotype the SNPs. Only 0.5% of each Gray zone and PM alleles were found among patient group, however, no disease association was noticed with repeat length. The rs25731 showed protection [OR:0.32; (0.13–0.76), p = 0.006] and rs4949 reported a 2.5-fold risk towards the disease predisposition [OR:2.46; (1.06–5.74), p = 0.031] but, both found insignificant after Bonferroni correction was done under different Genetic Models. Novel classification of genotype combinations, ‘Normal&Variant Homozygote’ [OR:2.89,(1.12–7.9), p < 0.05] and ‘Allele2-T-G’ haplotype block (6%vs.1%, p = 0.08) were noticed to be at marginal risk for POI. We demonstrated a susceptible role of the combined effect of variant allele-G and Allele-2 (repeat allele outside the normal range) for FXPOI. To support our findings of its first kind, further studies with large samples are warranted in understanding the role of FMR1 genetic variants in FXPOI etio-pathophysiology, the outcome might help in providing better reproductive treatment options for females, who are at risk for FXPOI.

Editorial: The Privatization of Work-Related Risk Control

Abstract This introduction starts by linking the privatization of work-related risk control to a political context in which social investment policies are prominent. Subsequently, a short overview of different forms of privatization is given. Finally, the different contributions to this special issue are introduced by either relating them to the governance or the consequences of privatization. Based on the contributions to the special issue, it is concluded first that the governance of privatized risk control poses difficult challenges of finding the right balance between public objectives and the involvement of private interests. Secondly, it is concluded that, by excluding or marginalizing the most vulnerable group, the privatization of risk control does not always achieve the equality of opportunities that social investment policies aim for. These risks of exclusion and marginalization seem to be particularly salient when the privatization of social investment policies is embedded in a context of retrenchment or a dualization of the labor market.

Comparative Effectiveness of Mechanical Valves and Homografts in Complex Aortic Endocarditis

The ideal surgical reconstruction of the aortic root in patients with complex endocarditis is controversial. We compared the short- and long-term outcomes between mechanical valves, bioprostheses, and homografts. We identified all patients undergoing an operation for active complex aortic endocarditis at our institution between 2003 and 2017. We grouped patients according to those who received a mechanical valve, bioprosthesis, or homograft. We used multiple logistic regression and proportional hazards models. To minimize confounding by indication, we used marginal risk adjustment to simulate that every patient would undergo (contrary to fact) all 3 operations. Of 159 patients with complex active endocarditis, 48 (30.2%) had a valve plus patch reconstruction, and 85 (53.4%) had a root replacement. Of all, 50 (31.5%) had a mechanical valve, 56 (35.2%) had a bioprosthesis, and 53 (33.3%) had a homograft. The groups were similar in age, sex, body mass index, comorbid conditions, organism, abscess location, and mitral involvement (all P > .05). However, patients receiving mechanical reconstructions were more likely to have native valve endocarditis (46% vs 37.5% vs 17%; P= .005) and less likely to undergo root replacement (32% vs 28.6% vs 100%; P < .001). Marginal risk-adjusted operative mortality was lowest for mechanical valves (4.8%) and highest for homografts (16.9%; P= .041). Long-term survival after root replacement was worse with homografts than with mechanical valve conduits (adjusted hazard ratio, 2.9; P= .045). In patients with complex endocarditis, mechanical valves are associated with similar, if not better, short- and long-term outcomes compared with homografts, even after adjusting for important baseline characteristics and limiting the analysis to root replacements only.

Different diagnostic groups and labour market marginalization among refugee youths

Abstract Background Refugees are at increased risk of labor market marginalization (LMM), which is of high Public Health importance. However, little is known whether specific multimorbidity patterns increase the risk of LMM in this group. We sought to examine whether different diagnostic groups associate with subsequent unemployment and disability pension in refugee youth as compared to their counterparts born in Sweden. Methodology We analyzed 249,245 individuals between the age of 16 and 26 at 31.12.2011 from a combined Swedish registry. Refugees were matched to five second-generation-native-born Swedes. LMM was defined as disability pension or &amp;gt; 180 days of unemployment, 2012-2015. Relative risks (RR) were calculated for 114 diagnostic groups (2009-11) with regard to the two outcome measures. Results The mean age was 23±1.7 years, 2,841 (1.1%) received disability pension and 16,323 (6.5%) individuals experienced unemployment. The majority of diagnostic groups was associated with a higher risk for unemployment and a lower risk for disability pension in refugees. Hypertensive diseases and external causes of morbidity showed higher risk ratios of unemployment for refugees compared to Swedish-born: RRs (95% Confidence Interval) 6.8 (3.16, 14.6) and 6.31 (4.45, 8.94), respectively. Diabetes and mental disorders were associated with higher risk estimates for disability pension in refugees: RRs (95% CI) 2.4 (1.02, 5.6) and 1.8 (0.80, 3.9), respectively. Conclusions Diagnoses are differentially associated with LMM in refugee youth as compared to Swedish-born individuals. In order to prevent LMM in refugees, early intervention for the identified diseases is important. Key message The importance of diagnostic groups for subsequent LMM differs for young refugees and Swedish-born individuals. Findings are also divergent regarding the measure of LMM.

28.M. Workshop: Mental ill-health and social exclusion among refugee minors/youth resettling in European countries

Abstract Globally, many countries have experienced the immigration of a growing number or refugee minors/youth. Many refugees have been exposed to traumatic events in their country of origin or during flight to their host country, putting issues of public mental health on the agenda. Mental ill-health can have a strong impact on social integration as it affects educational and occupational attainment and therefore increases the risk of labour market marginalisation. Mental ill-health can range from psychological distress to diagnosed disorders. Most frequently occurring are common mental disorders (CMDs), which include depressive, anxiety and post-traumatic stress disorders (PTSD). These disorders are characterised by an early age of onset, recurrent episodes and emerging comorbid disorders. Despite the size of the problem, research considering both mental ill-health and social integration in refugee minors/youth is severely underdeveloped and intervention studies are rare. Therefore, the overall aim of the consortium entitled REMAIN (REfugee Minors/youth And INtegration) is to gain knowledge on strategies to improve the social integration of refugee minors/youth with mental ill-health. The objective of this workshop is to present findings from etiological, prognostic and intervention studies carried out within the REMAIN consortium. The workshop aims to increase the audience' knowledge in an area of outmost Public Health importance. The reason of organising this workshop is based on the strong increases of young refugees in many countries worldwide and the resulting need for evidence based knowledge in the area of refugee's health and social integration. The added value of this workshop is due to the presentation of recent and solid findings from studies in 5 universities in 4 different European countries, offering a transnational perspective. Moreover, several studies are based on register data with long follow-up times and good data quality, which are not challenged by low response and high attrition rates during follow-up. Also findings from an intervention study will be presented. The proposed studies contribute with crucial information in a research field characterised by an enormous scientific knowledge gaps. The coherence between the presentations is guaranteed as all presentations deal with mental ill-health and social integration among refugee minors/youth. The format of the workshop implies five presentations and discussion with the participants of the workshop. The presentations will be of such a length that ample time for intensive interaction with the audience is guaranteed. After each presentation, the organiser/chair of the workshop will invite the audience for posing questions and comments regarding the findings presented. Moreover, as last part of the workshop, there will be time for a common discussion of the results and its societal and Public Health implications in a more overarching manner. Key messages Psychological interventions should be developed to address common mental disorders in refugee youth. These disorders worsen refugees' social integration in the new host country.

Identifying the systemically important banks of Turkey with the CoVaR method

The purpose of this paper is to measure the systemic risk contributions of Turkish banks and to identify the systemically important banks of Turkey during the period from 2005 to 2016. We apply the conditional value-at-risk (CoVaR) method proposed by Adrian and Brunnermeier (2009) using quantile regression. The study includes thirteen major banks of Turkey, including both public and private banks, out of a total of 52 banks. The banks are ranked in terms of their systemic risk contribution to the Turkish financial system based on their asset returns, macroeconomic variables and individual bank variables. The study reveals that Akbank, Garanti, Yapi Kredi and Isbank have the highest systemic risk contribution to the financial system when adding macroeconomic variables to the model. This ranking is changed to Yapi Kredi, Garanti, TEB, Sekerbank and Akbank when taking into account bank-specific variables. One surprising result is that risk in isolation and the spillover risks of public banks are smaller than in large private banks. Furthermore, the marginal systemic risk contributions of public banks are smaller than those of private banks. In conclusion, authorities improve the regulatory framework according to the context of CoVaR in addition to monitor the idiosyncratic risks of banks.

Perceptions of a COVID-19 education public service announcement in Nunukan Regency, North Kalimantan: a qualitative study

Indigenous populations experience a risk of socio-economic marginalization in health emergency, including COVID-19. Public service announcements (PSA) are promotional materials that address problems in an attempt to increase public awareness. North Kalimantan is one of the frontier, outermost, and least developed regions in Indonesia with 11 regional languages spoken. One of the districts with inadequate human resources in the area is Nunukan regency. The present study sought to understand how one group of people in Nunukan Regency reactions, interests, and impressions with the COVID-19 information found in Bugis and Toraja version of audio PSAs released by Health Empowerment and Education Project (HEUProject). The study belongs to qualitative research and used purposive sampling with seven participants from two sub-district in Nunukan Regency. The data is analyzed qualitative-thematically which is further interpreted and presented in the form of a description. Additionally, to see the variety of participants’ answers information transmission through PSAs, we analyzed the data using Tableau software 2020 version and presented the relative frequency of words with visual infographic. The study findings of the participants' immediate reactions were following the advice on the PSAs audio, for instance to keep the physical distance and washing their hands frequently. The most participants in this study have the willingness to hear, to understand, and also feel interested with the useful content in audio format that apparently improves their awareness of COVID-19 information. Overall, it is immediately apparent that the language, transmission of message, and information found in the HEUProject’s COVID-19 educational PSA were understood and engaged by participants in a way that it reflects on the pandemic situation. Our study supports the national usage of disease prevention with this type of media approach that could be used in public places in the future that may minimize the language divide.

Understanding and Explaining the Marginalization of Part-Time British Army Reservists

Recent changes in the British Army mean part-time reservists and full-time regulars need to become better integrated. However, there has been a long history of workplace tensions between the full-time and part-time elements in the British Army. This mirrors those found in many civilian workplaces. Focus group data with 105 full-time regular British Army soldiers confirmed that time and emotional commitment are strongly linked in a full-time professional workplace that has strong, definite, and enduring boundaries. This, alongside demands for conformity and stratification by rank explained the high risk of marginalization of part-time reservists. The legitimacy of part-time reservists, especially in the combat arms, was often challenged. Using this explanatory framework, some implications and practical ways that tensions may be reduced between full-time and part-time members of the British Army, and other armed forces facing similar tensions, were highlighted.

The cultural persona as nexus between structural marginalization and youth risk behavior.

Structural marginalization exerts its effects through multiple social-ecological levels down to the individual behavior of youth violence and related risks. However, there is very little research or theoretical literature documenting or specifying mechanisms, paths, and linkages across levels. This paper traces one path in which long-term structural constraints intersect with the adolescent development process via a construct called the cultural persona-a form of archetype or model that embodies the value-structure, role, and performance of violence and related risk behavior within the kinds of underground or street economies that develop and persist in high-poverty communities as an outcome of structural marginalization. This mechanism is described, together with its limitations, along with examples and recommendations for interventions and further research.

Coronavirus Human Infection Challenge Studies: Assessing Potential Benefits and Risks.

Human infection challenge studies (HCS) have been proposed as a means to accelerate SARS-CoV2 vaccine development and thereby help to mitigate a prolonged global public health crisis. A key criterion for the ethical acceptability of SARS-CoV2 HCS is that potential benefits outweigh risks. Although the assessment of risks and benefits is meant to be a standard part of research ethics review, systematic comparisons are particularly important in the context of SARS-CoV2 HCS in light of the significant potential benefits and harms at stake as well as the need to preserve public trust in research and vaccines. In this paper we explore several considerations that should inform systematic assessment of SARS-CoV-2 HCS. First, we detail key potential benefits of SARS-CoV-2 HCS including, but not limited to, those related to the acceleration of vaccine development. Second, we identify where modelling is needed to inform risk-benefit (and thus ethical) assessments. Modelling will be particularly useful in (i) comparing potential benefits and risks of HCS with those of vaccine field trials under different epidemiological conditions and (ii) estimating marginal risks to HCS participants in light of the background probabilities of infection in their local community. We highlight interactions between public health policy and research priorities, including situations in which research ethics assessments may need to strike a balance between competing considerations.

Notifications to Improve Engagement With an Alcohol Reduction App: Protocol for a Micro-Randomized Trial.

BackgroundDrink Less is a behavior change app that aims to help users in the general adult population reduce hazardous and harmful alcohol consumption. The app includes a daily push notification, delivered at 11 am, asking users to “Please complete your mood and drinking diaries.” Previous analysis of Drink Less engagement data suggests the current notification strongly influences how users engage with the app in the subsequent hour. To exploit a potential increase of vulnerability of excess drinking and opportunity to engage with the app in the evenings, we changed the delivery time from 11 am to 8 pm. We now aim to further optimise the content and sequence of notifications, testing 30 new evidence-informed notifications targeting the user’s perceived usefulness of the app.ObjectiveThe primary objective is to assess whether sending a notification at 8 pm increases behavioral engagement (opening the app) in the subsequent hour. Secondary objectives include comparing the effect of the new bank of messages with the standard message and effect moderation over time. We also aim to more generally understand the role notifications have on the overall duration, depth, and frequency of engagement with Drink Less over the first 30 days after download.MethodsThis is a protocol for a micro-randomized trial with two additional parallel arms. Inclusion criteria are Drink Less users who (1) consent to participate in the trial; (2) self-report a baseline Alcohol Use Disorders Identification Test score of 8 or above; (3) reside in the United Kingdom; (4) age ≥18 years and; (5) report interest in drinking less alcohol. In the micro-randomized trial, participants will be randomized daily at 8 pm to receive no notification, a notification with text from the new message bank, or the standard message. The primary outcome is the time-varying, binary outcome of “Did the user open the app in the hour from 8 pm to 9 pm?”. The primary analysis will estimate the marginal relative risk for the notifications using an estimator developed for micro-randomized trials with binary outcomes. Participants randomized to the parallel arms will receive no notifications (Secondary Arm A), or the standard notification delivered daily at 11 am (Secondary Arm B) over 30 days, allowing the comparison of overall engagement between different notification delivery strategies.ResultsApproval was granted by the University College of London’s Departmental Research Ethics Committee (CEHP/2016/556) on October 11, 2019, and The London School of Hygiene and Tropical Medicine Interventions Research Ethics Committee (17929) on November 27, 2019. Recruitment began on January 2, 2020, and is ongoing.ConclusionsUnderstanding how push notifications may impact engagement with a behavior change app can lead to further improvements in engagement, and ultimately help users reduce their alcohol consumption. This understanding may also be generalizable to other apps that target a variety of behavior changes.International Registered Report Identifier (IRRID)DERR1-10.2196/18690

The obesity paradox in critically ill patients: a causal learning approach to a casual finding

BackgroundWhile obesity confers an increased risk of death in the general population, numerous studies have reported an association between obesity and improved survival among critically ill patients. This contrary finding has been referred to as the obesity paradox. In this retrospective study, two causal inference approaches were used to address whether the survival of non-obese critically ill patients would have been improved if they had been obese.MethodsThe study cohort comprised 6557 adult critically ill patients hospitalized at the Intensive Care Unit of the Ghent University Hospital between 2015 and 2017. Obesity was defined as a body mass index of ≥ 30 kg/m2. Two causal inference approaches were used to estimate the average effect of obesity in the non-obese (AON): a traditional approach that used regression adjustment for confounding and that assumed missingness completely at random and a robust approach that used machine learning within the targeted maximum likelihood estimation framework along with multiple imputation of missing values under the assumption of missingness at random. 1754 (26.8%) patients were discarded in the traditional approach because of at least one missing value for obesity status or confounders.ResultsObesity was present in 18.9% of patients. The in-hospital mortality was 14.6% in non-obese patients and 13.5% in obese patients. The raw marginal risk difference for in-hospital mortality between obese and non-obese patients was − 1.06% (95% confidence interval (CI) − 3.23 to 1.11%, P = 0.337). The traditional approach resulted in an AON of − 2.48% (95% CI − 4.80 to − 0.15%, P = 0.037), whereas the robust approach yielded an AON of − 0.59% (95% CI − 2.77 to 1.60%, P = 0.599).ConclusionsA causal inference approach that is robust to residual confounding bias due to model misspecification and selection bias due to missing (at random) data mitigates the obesity paradox observed in critically ill patients, whereas a traditional approach results in even more paradoxical findings. The robust approach does not provide evidence that the survival of non-obese critically ill patients would have been improved if they had been obese.

A robust framework for risk parity portfolios

We propose a robust formulation of the traditional risk parity problem by introducing an uncertainty structure specifically tailored to capture the intricacies of risk parity. Typical minimum variance portfolios attempt to introduce robustness by computing the worst-case estimate of the risk measure, which is not intuitive for risk parity. Instead, our motivation is to shield the risk parity portfolio against noise in the estimated asset risk contributions. Thus, we present a novel robust risk parity model that introduces robustness around both the overall portfolio risk and the assets’ marginal risk contributions. The proposed robust model is highly tractable and is able to retain the same level of complexity as the original problem. We provide a general procedure by which to create an uncertainty structure around the asset covariance matrix. We quantify this uncertainty as a perturbation on the nominal covariance estimate, which allows us to intuitively embed robustness during optimization. We then propose a specific procedure to construct a robust risk parity portfolio through a factor model of asset returns. Computational experiments show that the robust formulation yields a higher risk-adjusted rate of return than the nominal model while maintaining a sufficiently risk-diverse portfolio.

Study on the status quo and countermeasures of “marginalization” of Marxist ideology in colleges and universities

This study involves a broad theoretical basis, based on China’s mainstream ideology, with Marxist ideology throughout the text. Firstly explains the ideological theory, Marxist ideology in Chinese colleges and universities be marginal risk discusses and combs, the induction and summary of marxism in China’s achievement at the same time, some problems also exist, timely find out the reasons, finally summarizes the present situation of the Marxist ideology in the marginalized, put forward the corresponding countermeasures, these countermeasures can insist on the guidance of the Marxist ideology position and leading role, and elevate the status of the mainstream ideology of colleges and universities.

Risk-Based Loan Pricing: Portfolio Optimization Approach with Marginal Risk Contribution

We consider a lender (bank) that determines the optimal loan price (interest rate) to offer to prospective borrowers under uncertain borrower response and default risk. A borrower may or may not accept the loan at the price offered, and both the principal loaned and the interest income become uncertain because of the risk of default. We present a risk-based loan pricing optimization framework that explicitly takes into account the marginal risk contribution, the portfolio risk, and a borrower’s acceptance probability. Marginal risk assesses the incremental risk contribution of a prospective loan to the bank’s overall portfolio risk by capturing the dependencies between the prospective loan and the existing portfolio and is evaluated with respect to the value-at-risk and conditional value-at-risk measures. We examine the properties and computational challenges of the formulations. We design a reformulation method based on the concavifiability concept to transform the nonlinear objective functions and to derive equivalent mixed-integer nonlinear reformulations with convex continuous relaxations. We also extend the approach to multiloan pricing problems, which feature explicit loan selection decisions in addition to pricing decisions. We derive formulations with multiple loans that take the form of mixed-integer nonlinear problems with nonconvex continuous relaxations and develop a computationally efficient algorithmic method. We provide numerical evidence demonstrating the value of the proposed framework, test the computational tractability, and discuss managerial implications. This paper was accepted by Chung Piaw Teo, optimization.

Impact of Loneliness on Brain Health and Quality of Life Among Adults Living With HIV in Canada.

People aging with HIV are at risk for loneliness, with stigmatization and economic marginalization added to the health challenges arising from chronic infection. This study provides evidence for the extent, contributors, and consequences of loneliness in people living with HIV, focusing on brain health and quality of life. Cross-sectional data from 856 middle-aged and older adults living with HIV recruited from 5 urban specialty clinics in Canada were drawn from the inaugural visit of the Positive Brain Health Now cohort study. Participants completed an extensive assessment of biopsychosocial variables. The prevalence, severity, and quality of life impact of self-reported loneliness were described. Clinical and environmental factors hypothesized as contributing to loneliness, and the consequences of loneliness on health and function were identified using logistic, ordinal, and linear regression. Eighteen percent reported being "quite often" and 46% "sometimes" lonely. Those with more loneliness were younger, less mobile, suffered more financial hardship, and were more likely to use opioids. HIV symptoms, pain, fatigue, low motivation, stigma, and unemployment were related to loneliness. Loneliness increased the odds of cognitive impairment, low mood, stress, and poor physical health. Those who were "quite often" lonely were over 4 times more likely to report poor or very poor quality of life than those who were "almost never" lonely. Loneliness is common in middle-aged and older people living with HIV in Canada. Many of the associated factors are modifiable, offering novel targets for improving brain health, general health, and quality of life in HIV.

Integrating direct employee voice within the framework of worker representation: The role of an Italian trade union in organising disintermediation

Facing the spread of management-led direct employee voice, trade unions are stuck with a theoretical and practical dilemma: organising against the disintermediation threats or accepting the risk of marginalisation and partnering with management to at least secure mutual gains. This article casts light on organising disintermediation as a chance for trade unions to overcome the ‘ organising against vs surrendering to disintermediation’ trade-off, by taking the lead in the promotion, regulation and implementation of direct employee voice. The analysis of FIM-CISL Brescia shows that far from exclusively being a link to organisational performance and a challenge to union intermediation, direct employee voice may become a trade union goal, being the expression of employee self-determination and human dignity. Pursuing this goal translates into a multifaceted change for the trade union, regarding both its internal ( organising) and external ( partnership) dimension.

Recommendations for integration of foundational and clinical sciences throughout the pharmacy curriculum

IntroductionPharmacy faculty have the often difficult task of translating and incorporating existing concepts and advances from the foundational sciences into the clinical sciences and practice. This commentary focuses on content integration as a curricular and educational strategy, outcomes data from integration, and recommendations for programs employing or considering curricular integration. CommentaryIntegration of foundational and clinical sciences across the curriculum has been emphasized in accreditation standards but met with mixed reactions by faculty across different disciplines in the academy. Many pharmacy programs have already incorporated some level of integration in didactic courses. However, most report coordination of curricular delivery rather than higher levels of integration in which different disciplines work together to design and deliver instructional materials across the entire curriculum. ImplicationsCurricular integration models should be optimized to minimize or eliminate the risks of marginalization of foundational sciences in pharmacy curricula. A significant problem in implementing curricular integration is determining the appropriate balance between foundational and clinical sciences. Well-designed curricular integration with ongoing reinforcement that builds in complexity over time could enhance knowledge retention, critical thinking abilities, and clinical decision making. Further research is needed into the outcomes achieved from various integrated curricular approaches in pharmacy education.

Outcome of tantalum rod insertion in the treatment of osteonecrosis of the femoral head with minimum follow-up of 1 year: a meta-analysis and systematic review.

Osteonecrosis of the femoral head (ONFH) is a debilitating disease that can cause deformity and collapse of the femoral head, thus leading to the development of degenerative joint disease that can incapacitate the patient with pain and reduction in hip mobility. This study aims to determine the safety and efficacy of tantalum rod insertion in the treatment of ONFH with a minimum follow-up period of 1 year. A multi-database search was performed according to Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines. Data from studies assessing the clinical and radiological outcomes as well as complications of tantalum rod insertion in the treatment of ONFH with a minimum follow-up period of 1 year were extracted and analyzed. Ten studies were included in this meta-analysis, consisting of 550 hips. There was a statistically significant increase in HHS (MD = 30.35, 95% CI: 20.60–40.10, P < 0.001) at final follow-up versus pre-operative scores. The weighted pooled proportion (PP) of radiographic progression of ONFH was 0.221 (95% CI: 0.148–0.316), while that of progression into femoral head collapse was 0.102 (95% CI: 0.062–0.162). Conversion to total hip arthroplasty (THA) had a PP of 0.158 (95% CI: 0.107–0.227) with a mean weighted period of 32.4 months (95% CI: 24.9–39.9 months). Subgroup analysis of conversion to THA when tantalum rods were used in conjunction with bone grafting (PP = 0.150, 95% CI: 0.092–0.235) showed a marginal risk reduction than when compared with subgroup analysis of tantalum rods being used alone (PP = 0.154, 95% CI: 0.078–0.282). Tantalum rod is a safe alternative option to the current joint-preserving procedures available in the treatment of ONFH. However, more studies are needed to investigate and identify the most appropriate patients who would benefit most and the synergistic effect brought on by the use of complementary biological augmentation of bone grafting or stem cells with tantalum rods.

When Is a Complete-Case Approach to Missing Data Valid? The Importance of Effect-Measure Modification

When estimating causal effects, careful handling of missing data is needed to avoid bias. Complete-case analysis is commonly used in epidemiologic analyses. Previous work has shown that covariate-stratified effect estimates from complete-case analysis are unbiased when missingness is independent of the outcome conditional on the exposure and covariates. Here, we assess the bias of complete-case analysis for adjusted marginal effects when confounding is present under various causal structures of missing data. We show that estimation of the marginal risk difference requires an unbiased estimate of the unconditional joint distribution of confounders and any other covariates required for conditional independence of missingness and outcome. The dependence of missing data on these covariates must be considered to obtain a valid estimate of the covariate distribution. If none of these covariates are effect-measure modifiers on the absolute scale, however, the marginal risk difference will equal the stratified risk differences and the complete-case analysis will be unbiased when the stratified effect estimates are unbiased. Estimation of unbiased marginal effects in complete-case analysis therefore requires close consideration of causal structure and effect-measure modification.