Relative Attrition Research Articles

Differential attrition in randomized controlled trials of digital mental health interventions in the workplace: A systematic review and meta-analysis (EMPOWER H2020 project)

IntroductionDigital interventions have been found to be successful in preventing occupational mental health concerns, however, they seem to be affected by attrition bias through high attrition rates and differential attrition. Differential attrition arises when the rates of participant dropouts differ across different treatment conditions and is considered a significant challenge to internal validity.ObjectivesWe aimed at systematically review and meta-analyse differential attrition of digital mental health interventions in the workplace setting.MethodsOn January 2, 2022, we performed a search in the following electronic databases: PubMed, Scopus, and Web of Science Core. We utilized a combination of terms from five distinct areas, namely mental health, intervention, workplace, implementation, and study design. The study encompassed adult employees who took part in a randomized control trial aimed at preventing mental health issues in the workplace through an online intervention. A team of six reviewers collaborated on the study selection process, while two independent researchers conducted the data extraction for the selected studies. We performed a meta-analysis of the log-transformed relative attrition rates of the included studies using a random-effects model with limited maximum-likelihood (REML) estimation to account for the degree of heterogeneity.ResultsA total of 19 studies were included in the meta-analysis. For baseline to post-intervention, the average total attrition was 26.27% (SD = 21.16%, range = 0 – 66.3%) and the random effects model revealed a higher attrition rate in the intervention group compared to the control group, with a pooled risk ratio of 1.05 (95% CI: 1.01 - 1.10, p = .014). For baseline to follow-up measurement the average total attrition was 27.71% (SD = 20.80%, range = 0 – 67.78%), however, in this case the random effects model did not indicate a higher attrition in the intervention group when compared to the control group (pooled risk ratio = 1.05, 95% CI: 0.98 – 1.12, p = .183).ConclusionsThere is an indication of higher attrition in the intervention group as compared to the control group in occupational e-mental health interventions from baseline to post-intervention, however this does not seem to be the case for baseline to follow-up attrition. These results should be taken into account in the design process of studies and statistical analyses should be adapted to counteract the bias that could result from differential attrition.Disclosure of InterestNone Declared

Long-term retention on antiretroviral treatment after enrolment in prevention of vertical HIV transmission services: a prospective cohort study in Dar es Salaam, Tanzania.

To prevent vertical HIV transmission and ensure healthy mothers and children, pregnant women with HIV must remain on antiretroviral treatment (ART) for life. However, motivation to remain on ART may decline beyond the standard 2-year breastfeeding/postpartum period. We assessed attrition and retention in ART care among women with HIV up to 6 years since enrolment in vertical transmission prevention services in Dar es Salaam, Tanzania. A prospective cohort of 22,631 pregnant women with HIV were enrolled in vertical transmission prevention services between January 2015 and December 2017 in routine healthcare settings and followed-up to July 2021. Kaplan-Meier was used to estimate time to ART attrition (died, stopped ART or was lost to follow-up [no show ≥90 days since scheduled appointment]) and the proportion retained in care. Cox proportional hazard models were used to estimate adjusted hazard ratios (aHR) of ART attrition in relation to predictors. Participants were followed-up to 6 years for a median of 3 years (IQR: 0.1-4). The overall ART attrition rate was 13.8 per 100 person-years (95% CI: 13.5-14.1), highest in the first year of enrolment at 27.1 (26.3-27.9), thereafter declined to 9.5 (8.9-10.1) in year 3 and 2.7 (2.1-3.5) in year 6. The proportion of women retained in care were 78%, 69%, 63%, 60%, 57% and 56% at 1, 2, 3, 4, 5 and 6 years, respectively. ART attrition was higher in young women aged <20 years (aHR 1.63, 95% CI: 1.38-1.92) as compared to 30-39 year-olds and women enrolled late in the third versus first trimester (aHR 1.29, 95% CI: 1.16-1.44). In contrast, attrition was lower in older women ≥40 years, women who initiated ART before versus during the index pregnancy and women attending higher-level health facilities. ART attrition among women with HIV remains highest in the first year of enrolment in vertical transmission prevention services and declines markedly following a transition to chronic HIV care. Targeted interventions to improve ART continuity among women with HIV during and beyond prevention of vertical transmission are vital to ending paediatric HIV and keeping women and children alive and healthy.

2000–2023 over two decades of ICH S7A: has the time come for a revamp?

The ICH S7A guideline on safety pharmacology studies released over 20 years ago largely achieved its objective “to help protect clinical trial participants and patients receiving marketed products from potential adverse effects of pharmaceuticals”. Although, Phase I clinical trials are generally very safe, the incidence and severity of adverse events, the safety related attrition and product withdrawal remain elevated during late-stage clinical development and post approval, a proportion of which can be attributed at least in part to safety pharmacology related issues. Considering the latest scientific and technological advancements in drug safety science, the paradigm shift of the drug discovery and development process and the continuously evolving regulatory landscape, we recommend revisiting, adapting and evolving the ICH S7A guideline. This might offer opportunities i) to select and progress optimized drugs with increased confidence in success, ii) to refine and adapt the clinical monitoring at all stages of clinical development resulting in an optimized benefit/risk assessment, iii) to increase likelihood of regulatory acceptance in a way compatible with an expedited and streamlined drug discovery and development process to benefit patients and iv) to avoid the unnecessary use of animals in ‘tick-the-box’ studies and encourage alternative approaches. As presented in the article, several options could be envisioned to revisit and adapt the ICH S7A taking into consideration several key features.

Systematic review and meta analysis of differential attrition between active and control arms in randomized controlled trials of lifestyle interventions in chronic disease

BackgroundAttrition is a major obstacle for lifestyle interventions sustained for the medium-to-long term and can have significant consequences on the internal validity of a trial. When the degree of attrition differs between active and control arms this is termed differential attrition and is an important consideration during initial stages of trial planning.ObjectivesThe primary research question of this study was: what is the differential attrition between treatment arms in lifestyle interventions for prevalent chronic diseases?MethodsWe performed a systematic review and meta-analysis of 23 studies involving a lifestyle intervention component in cohorts with chronic diseases. The search accessed three databases: Scopus, Medline Ovid and Web of Science. Attrition between treatment arms was analysed using a random-effects model and examined the relationship between the relative attrition and potential moderators, such as time to final follow-up, time to first follow-up, type of disease, type of control, type of intervention and length of treatment.ResultsThe pooled risk ratio was 1.00 (95% CI 0.97 – 1.03) and only one study fell outside this range. A univariable association was described between the pooled risk ration and length (years) to final follow-up, which did not remain in the multivariable model.ConclusionsUltimately, we found no evidence of differential attrition in medium-to-long term lifestyle intervention studies for chronic disease, increasing confidence in conducting such studies with minimal potential of attrition bias.Trial registrationPROSPERO registration number CRD42018084495.

Foreign body impaction in the maxillofacial region: A case report

This article describes the presence of foreign bodies which are asymptomatic in nature in the orofacial soft tissue spaces. The patient had reported to the Department of Conservative Dentistry and Endodontics with sensitivity as the chief complain in the lower right back tooth region. Clinical Examination were suggestive of generalised attrition in relation to #46. Radiographic findings revealed a well defined radio-opacity in relation to distal root of #46. This radiolucency was seen to have moved to the mesial root when another radiograph of the same tooth was taken. An orthopantomograph and CBCT was then taken to study the case better which apparently showed around 12 such radio-opacities lodged in the oral cavity with the patient being absolutely asymptomatic of it. The provisional diagnosis of foreign bodies embedded in the soft tissue was considered.

Bench scale analysis of the physical attrition properties for copper-ferri-aluminate oxygen carriers during chemical looping combustion

Abrasion and fragmentation related attrition has been deemed as one of the major design challenges for the development of oxygen carriers for chemical looping process concepts and their implementation. Since the technology seeks to replace conventional power generation, oxygen carrier lifetime is a critical parameter as it can impact the potential competitive nature for the implementation of the process concept. In this study, attrition propensity is examined for two novel carrier materials CuFeAlO4 and CuFe1.5Al0.5O4 in a bench scale fluidized bed reactor unit under reacting conditions. Bench scale outcomes were compared to attrition outcomes from a sub pilot operation to determine comparability of scale. Routes by which attrition performance can be improved are proposed and validated through examining the solid-state chemistry of the carrier system and evaluation method. The study suggests that material structure, maturation and microstructure can play a major role in physical attrition propensity.

Patterns of change in telomere length over the first three years of life in healthy children

There is growing interest in the use of telomere length as a biomarker of health and a predictor of later morbidity and mortality. However, little is known about developmentally expected telomere erosion over the first years of life. This gap hinders our ability to interpret the meaning of relative telomere length and rate of attrition in relation to risk factors and health outcomes. The overall goal of this study was to examine the rate of relative telomere length attrition in a large, normative sample of healthy children (N = 630) followed from infancy to three years of age. A secondary goal was to explore associations between sociodemographic characteristics and telomere erosion over this time period. Relative telomere length was assessed from DNA in saliva samples collected in infancy (M = 8.6 months), age 2 years (M = 25.2 months), and age 3 years (M = 38.3 months). In the sample as a whole, relative telomere length decreased from infancy to 2 years but remained stable from 2 years to 3 years. Notably, increases in relative telomere length were observed in 29 % of children between infancy and 2 years of age and in 46 % of children between 2 and 3 years of age; 62 % of children showed both increases and decreases in relative telomere length across the study period. Females showed longer relative telomere length than males, regardless of timepoint. There was some evidence that parental age and family finances were associated with changes in child relative telomere length across time. Overall, the findings suggest that telomere length attrition is not uniform across the early years of life, with the most rapid attrition occurring during the first two years, and that increases as well as decreases in telomere length during this period are commonly observed.

Attrition rates in trials for adolescents and young adults at clinical high-risk for psychosis: A systematic review and meta-analysis.

Treatment of those at clinical high-risk (CHR) for developing psychosis may lead to preventive strategies. However, attrition in trials may hamper efforts to detect effective changes and lead to bias. Our objective was to synthesize the relative attrition rates in clinical trials conducted in CHR for psychosis samples. We searched the following electronic databases: MEDLINE, Embase, PsycINFO, CINAHL and EBM with no restrictions. Inclusion criteria was any treatment-based randomized controlled trial (RCT) conducted in CHR samples that reported attrition. Relative attrition rates were calculated using random-effects meta-analysis, stratified by time, and reported as odds ratios (ORs), proportions, and 95% confidence intervals (CIs). Twenty-one RCTs met our inclusion criteria, including a total of 2260 CHR participants. Attrition rates between all treatment types identified were not statistically different from control treatments at any time-point. When accessing overall trial attrition, the pooled attrition rate was 29.57% (95% CI = 23.84-35.63%) with statistically significant heterogeneity (I2 = 88.70%; P < .001). Furthermore, 11 trials had a subsequent follow-up after the intervention was conducted and the pooled attrition was 33.96% (95% CI = 24.94-43.59%). When examining predictors of attrition, no statistically significant subgroup differences were observed in attrition rates. Almost one third of CHR participants will not complete participation in an RCT, however no predictors were found to be statistically significantly related to attrition. Methods to account for missing data and attrition are warranted in CHR trials to account for potential biases associated with high attrition rates.

Comparison of Two Different Non-Radiographic Mixed Dentition Analysis

Objective: To evaluate the applicability of two different non-radiographic mixed dentition analysis in school going children of Aligarh district, India. Material and Methods: Mesiodistal dimension was measured on the dental casts of 120 school going children with electronic digital vernier caliper. The following inclusion criteria were adopted: presence of all fully erupted permanent teeth; no congenital craniofacial anomalies; no previous history of orthodontic treatment; and presence of intact dentition with no proximal caries, restoration, or age related attrition. Predicted values of canines and premolars were obtained from Moyer’s at 75th percentile and Tanaka and Johnston mixed dentition analysis. Descriptive statistics were used to calculate the mean and standard deviation. Paired observations were compared by t ‑ test. The level of significance was at p<0.001. Results: The mean difference between the predicted and the actual value of canines and premolars using Moyer’s probability table at 75th percentile and Tanaka and Johnston regression equation were statistically significant. No significant differences were found between Moyer’s analysis 75th percentile and Tanaka and Johnston mixed dentition analysis in both arch and sexes. Conclusion: These two non-radiographic mixed dentition analysis overestimated the mesiodistal width of canines and premolars.

Military Occupational Outcomes in Canadian Armed Forces Personnel with and without Deployment-Related Mental Disorders.

Mental disorders are common in military organizations, and these frequently lead to functional impairments that can interfere with duties and lead to costly attrition. In Canada, the military mental health system has received heavy investment to improve occupational outcomes. We investigated military occupational outcomes of diagnosed mental disorders in a cohort of 30,513 personnel who deployed on the Afghanistan mission. Cohort members were military personnel who deployed on the Afghanistan mission from 2001 to 2008. Mental disorder diagnoses and their attribution to the Afghanistan mission were ascertained via medical records in a stratified random sample (n = 2014). Career-limiting medical conditions (that is, condition-associated restrictions that reliably lead to medically related attrition) were determined using administrative data. Outcomes were assessed from first Afghanistan-related deployment return. At 5 years of follow-up, the Kaplan-Meier estimated cumulative fraction with career-limiting medical conditions was 40.9% (95% confidence interval [CI] 35.5 to 46.4) among individuals with Afghanistan service-related mental disorders (ARMD), 23.6% (CI 15.5 to 31.8) with other mental disorders, and 11.1% (CI 8.9 to 13.3) without mental disorders. The adjusted Cox regression hazard ratios for career-limiting medical condition risk were 4.89 (CI 3.85 to 6.23) among individuals with ARMD and 2.31 (CI 1.48 to 3.60) with other mental disorders, relative to those without mental disorders. Notwithstanding the Canadian military's mental health system investments, mental disorders (particularly ARMD) still led to a high risk of adverse military occupational outcomes. Such investments have intrinsic value but may not translate into reduced medically related attrition without improvements in prevention and treatment effectiveness.

Statistical power analysis of cardiovascular safety pharmacology studies in conscious rats

Cardiovascular (CV) toxicity and related attrition are a major challenge for novel therapeutic entities and identifying CV liability early is critical for effective derisking. CV safety pharmacology studies in rats are a valuable tool for early investigation of CV risk. Thorough understanding of data analysis techniques and statistical power of these studies is currently lacking and is imperative for enabling sound decision-making. MethodsData from 24 crossover and 12 parallel design CV telemetry rat studies were used for statistical power calculations. Average values of telemetry parameters (heart rate, blood pressure, body temperature, and activity) were logged every 60s (from 1h predose to 24h post-dose) and reduced to 15min mean values. These data were subsequently binned into super intervals for statistical analysis. A repeated measure analysis of variance was used for statistical analysis of crossover studies and a repeated measure analysis of covariance was used for parallel studies. Statistical power analysis was performed to generate power curves and establish relationships between detectable CV (blood pressure and heart rate) changes and statistical power. Additionally, data from a crossover CV study with phentolamine at 4, 20 and 100mg/kg are reported as a representative example of data analysis methods. ResultsPhentolamine produced a CV profile characteristic of alpha adrenergic receptor antagonism, evidenced by a dose-dependent decrease in blood pressure and reflex tachycardia. Detectable blood pressure changes at 80% statistical power for crossover studies (n=8) were 4–5mmHg. For parallel studies (n=8), detectable changes at 80% power were 6–7mmHg. Detectable heart rate changes for both study designs were 20–22bpm. DiscussionBased on our results, the conscious rat CV model is a sensitive tool to detect and mitigate CV risk in early safety studies. Furthermore, these results will enable informed selection of appropriate models and study design for early stage CV studies.

Telomere length is highly inherited and associated with hyperactivity-impulsivity in children with attention deficit/hyperactivity disorder.

Telomere length (TL) is highly heritable, and a shorter telomere at birth may increase the risk of age-related problems. Additionally, a shorter TL may represent a biomarker of chronic stress and has been associated with psychiatric disorders. However, no study has explored whether there is an association between TL and the symptoms of one of the most common neurodevelopmental disorders in childhood: Attention Deficit/Hyperactive Disorder (ADHD). We evaluated 61 (range, 6–16 years) ADHD children and their parents between 2012 and 2014. TL was measured with a quantitative polymerase chain reaction method with telomere signal normalized to the signal from a single copy gene (36B4) to generate a T/S ratio. Family data was processed through a generalized estimated equations (GEE) model to determine the effect of parental TL on children TL. Inattentive and hyperactive-impulsive symptoms were also evaluated in relation to TL. For the first time, we found general heritability to be the major mechanism explaining interindividual TL variation in ADHD (father-child: 95% CI = 0.35/0.91, p < 0.001; mother-child: 95% CI = 0.38/0.74, p < 0.001). The hyperactive-impulsive dimension of ADHD was related with children’s TL (r = −339, p = 0.008) and maternal TL (r = −264, p = 0.047), but not with paternal TL (p > 0.05). The ADHD inattentive dimension was not significant associated with TL in this study (p > 0.05). TL was shown to be a potential biomarker of the ADHD symptoms burden in families affected by this neurodevelopmental disorder. However, it is crucial that future studies investigating the rate of telomere attrition in relation to psychiatric problems to consider the strong determination of TL at birth by inheritance.

Attrition of catalyst particles in a laboratory-scale fluidized-bed reactor

Attrition of fluid catalytic cracking catalysts is investigated in a laboratory-scale fluidized bed. It is shown that the catalyst attrition arises from a mixed mechanism of particle fragmentation and surface abrasion. The measured conventional attrition rate always decreases with time, even for a long-time attrition; therefore, a relative attrition rate is suggested. Experiments indicate that after a nonsteady-state attrition where the measured relative attrition rate decreases with time, the attrition gets into a steady state and the measured relative attrition rate tends to a constant value. Furthermore, the time-dependence of particle attrition is discussed. It is seen that the widely-used Gwyn equation cannot model the catalyst attrition accurately. Alternatively, an exponential decay attrition model is proposed and confirmed to describe the time-dependent attrition behavior. It is found that the model parameters have definite meanings and are strongly related to the particle properties, fluidization conditions and fluidized bed structure.

Exploring the interplay between abrasive attrition and separation in cyclones

It is widely known that higher cyclone inlet velocities produce a finer and tighter gas–particle separation at the cost of higher particle attrition. Few models exist that study the simultaneous interplay between these two effects in detail. In this work we present a series of progressively more complex models of abrasive attrition and cyclone separation in a circulating fluidized bed (CFB) riser.The simplest of these models treats the in-situ particle size distribution (PSD) as that of the feed material, computes attrition based on a constant diameter reduction rate with instantly vanishing fines, and uses a simple two parameter cyclone grade efficiency model. This simple model is studied as a function of feed PSD, relative attrition rate, and cyclone grade efficiency parameters. The consequences of adding more complexity to the model – via a population balance (PB) computation of the true in-situ PSD, size dependent attrition, non-vanishing attrited fines, more detailed cyclone modeling, etc – are examined as well.The purpose of these exercises is to understand the mechanistic interplay between attrition and cyclone separation efficiency and evaluate the necessity of increased model complexity for accurate prediction. From this work, it was determined that in many practically operated regimes (relatively low attrition and reasonably low cut sizes) all models give roughly the same results. However, the more complex models are useful for understanding upset and worst case scenarios as well as for systems designed in other operating regimes.

Differential attrition in health behaviour change trials: A systematic review and meta-analysis

Objective: Attrition is a common problem in health behaviour change (HBC) trials. When the degree of attrition differs between treatment conditions, then this is called differential attrition and is regarded as a major threat to internal validity. The primary research question of this study was: how often and to what degree does differential attrition occur in HBC trials?Design: A systematic review and meta-analysis of a random selection of HBC trials (k = 60). We meta-analysed the relative attrition rates using a random-effects model and examined the relationship between the relative attrition rates and the potential moderators: the amount of human contact in delivery and the intensity of the intervention/control condition, the type of control condition, and the follow-up intensity and duration.Main outcome measures: Relative attrition rates.Results: The average attrition rate was 18% (SD = .15; M = .15) in the intervention and 17% (SD = .13; M = .13) in the control conditions. The estimated average relative attrition rate was 1.10 (95% CI: 1.01–1.20, p = .02), suggesting an overall higher attrition rate of 10% in the intervention conditions. This relative attrition rate was not related to any of the potential moderators.Conclusion: There is indication of a slightly higher amount of attrition on average in the intervention conditions of HBC trials.

Telomere biology is differently affected within clinical subsets of systemic sclerosis and points towards different downstream defects

Results We observed a significant age related telomere attrition in healthy controls and lcSSc patients (Both p< 0.001), but not in dcSSc patients. In the immune cell subset specific analysis we observed significant shorter telomeres in B cells and myeloid dendritic cells of both lcSSc and dcSSc patients (B-Cells p=0.014, p=0.002 & myDCs p=0.019, p=0.004 respectively). PDCs and T cells were significantly shorter in dcSSc patients only (p=0.001 and p=0.003 respectively). In addition, we observed in early SSc, that B cells exhibit a significant upregulation of the telosome genes SIRT6, RIF1 and WRN (after correction for multiple testing p=0.03, 0.006 and 0.048 respectively). In later disease there is a significant higher expression of HDAC9 in monocytes from dcSSc compared to lcSSc patients. Intriguingly, in PDCs of diffuse SSc patients, regardless whether it is early or progressed disease the expression of SIRT1 is significantly lower (p=0.002 in all comparisons).

A Review of Military Predeployment Stress Tolerance Training

Stress-induced psychological disorders and related attrition are major concerns for the U.S. Military. In fact, the Marine Corps has identified “mental toughness,” a construct including psychological resilience, among its critical competencies. In response to the psychological sequelae of exposure to stressful and potentially traumatic environments, the Services have recently implemented programs designed to promote stress tolerance. However, empirical evidence to support the efficacy of these training efforts is sorely lacking. As a result, these programs are often disjoint, cross-sectional, and delivered haphazardly. As a preliminary step toward addressing these issues, this outlines the efforts currently in use by the armed services, as well as those recommended by related communities. We present the potential shortcomings of these contemporary efforts, identify best-of-breed approaches and outcomes, and recommend next steps to improve resilience training efforts.

Individual Therapy Attrition Rates in a Low-Intensity Service: A Comparison of Cognitive Behavioural and Person-Centred Therapies and the Impact of Deprivation

This paper looks at attrition in relation to deprivation and type of therapy - CBT or person-centred counselling. Case notes of all those referred in a 4-month period (n = 497) were assessed for those who failed to opt-in; those who opted-in but failed to attend first appointment and those who attended first appointment but subsequently dropped-out. Significant numbers failed to opt-in, attend first appointment or dropped out during therapy. There were no differences between CBT and PCT. Those from the most deprived areas were less likely to opt-in. We need to develop better approaches to attracting and maintaining contact with individuals complaining of common mental health problems.

Attrition and Adherence Rates of Sustained vs. Intermittent Exercise Interventions

No conclusions have been drawn regarding the relative attrition and adherence rates associated with sustained vs. intermittent exercise programs. The study aims to systematically examine randomized controlled exercise intervention trials that report attrition and/or adherence rates to sustained vs. intermittent aerobic exercise programs. A comprehensive literature search was conducted, and references from qualifying articles were searched for additional papers. Fourteen articles met inclusion criteria, capturing 783 (76% female) enrolled and 599 (74% female) retained participants (mean age = 42.3 ± 6.6years). Study durations ranged from 8weeks to 18months (mean duration = 22.7 ± 21.9weeks). Although results varied, no consistent differences in attrition or adherence rates between sustained and intermittent exercise protocols were revealed. Given the universally low rate of regular exercise participation and the ongoing problem of adherence to exercise protocols, the field may benefit from randomized controlled trials examining sustained vs. intermittent exercise programs in greater depth.

Vocabulary forgetting, L1 and L2 memory representations and years of english disuse: investigating the possible relations

This article aims to investigate the loss of vocabulary after years of English disuse among Iranian teachers. Specifically, it strives to find the effect of period of English disuse on lexical attrition of graduated teachers, and also the cut-of point for lexical attrition in relation to years of English disuse. In addition, it tries to examine if after years of English disuse, teachers will perform better in Persian to English translation or English to Persian translation. 210 teachers participated in the study. Two translation tasks were employed for eliciting the data. The findings of the study revealed that Iranian teachers forget more than 50% of their word knowledge after 2 years and 90% of this knowledge will fade after 8 years. Also, it was found that after years of English disuse, English to Persian translation attrition was less than attrition in Persian to English translation. Some implications would be suggested for decreasing the degree of attrition among Iranian teachers. Keywords: Attrition, language disuse, L1, Iranian teachers, L2.