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BMC Public Health Sep 2023There are many ways in which selection bias might impact COVID-19 research. Here we focus on selection for receiving a polymerase-chain-reaction (PCR) SARS-CoV-2 test...
BACKGROUND
There are many ways in which selection bias might impact COVID-19 research. Here we focus on selection for receiving a polymerase-chain-reaction (PCR) SARS-CoV-2 test and how known changes to selection pressures over time may bias research into COVID-19 infection.
METHODS
Using UK Biobank (N = 420,231; 55% female; mean age = 66.8 [SD = 8·11]) we estimate the association between socio-economic position (SEP) and (i) being tested for SARS-CoV-2 infection versus not being tested (ii) testing positive for SARS-CoV-2 infection versus testing negative and (iii) testing negative for SARS-CoV-2 infection versus not being tested. We construct four distinct time-periods between March 2020 and March 2021, representing distinct periods of testing pressures and lockdown restrictions and specify both time-stratified and combined models for each outcome. We explore potential selection bias by examining associations with positive and negative control exposures.
RESULTS
The association between more disadvantaged SEP and receiving a SARS-CoV-2 test attenuated over time. Compared to individuals with a degree, individuals whose highest educational qualification was a GCSE or equivalent had an OR of 1·27 (95% CI: 1·18 to 1·37) in March-May 2020 and 1·13 (95% CI: 1.·10 to 1·16) in January-March 2021. The magnitude of the association between educational attainment and testing positive for SARS-CoV-2 infection increased over the same period. For the equivalent comparison, the OR for testing positive increased from 1·25 (95% CI: 1·04 to 1·47), to 1·69 (95% CI: 1·55 to 1·83). We found little evidence of an association between control exposures, and any considered outcome.
CONCLUSIONS
The association between SEP and SARS-CoV-2 testing changed over time, highlighting the potential of time-specific selection pressures to bias analyses of COVID-19. Positive and negative control analyses suggest that changes in the association between SEP and SARS-CoV-2 infection over time likely reflect true increases in socioeconomic inequalities.
Topics: Female; Humans; Aged; Male; Selection Bias; COVID-19; Pandemics; COVID-19 Testing; SARS-CoV-2; Communicable Disease Control; Educational Status
PubMed: 37752486
DOI: 10.1186/s12889-023-16767-5 -
Deutsches Arzteblatt International Dec 2023The long-term course of protection against severe COVID-19 courses by vaccine-induced or hybrid immunity in Germany is unclear. (Observational Study)
Observational Study
BACKGROUND
The long-term course of protection against severe COVID-19 courses by vaccine-induced or hybrid immunity in Germany is unclear.
METHODS
We studied 146 457 cases aged 60-99 years in the German federal state of Bavaria who were immunized against COVID-19 and tested positive for it from February 2022 to January 2023. We calculated adjusted hazard ratios for a severe course (hospitalization or death due to COVID-19) for different intervals between the onset of full primary or booster immunity and the date of the infection.
RESULTS
3342 (2.3%) severe courses of COVID-19 were observed in the first 60 days after the infection. The risk of a severe course rose with the interval between the onset of immune protection and the infection (adjusted hazard ratios and 95% confidence intervals at 6, 9, 12, and 15 months: 1.14 [1.08; 1.20]; 1.33 [1.24; 1.42]; 1.39 [1.25; 1.54]; 1.61 [1.35; 1.93]). The risk rose more slowly when mRNA-based vaccines were used exclusively. In a previous study, we observed 82% initial efficacy in cases aged 60 and above who received a booster vaccination (compared to unvaccinated cases) and an absolute risk reduction of 2.1%. If one extrapolates these findings to the current study, the residual efficacy and absolute risk reduction are found to be approximately 71% and 1.8% (respectively) at 6 months, and 32% and 0.8% at 15 months.
CONCLUSION
These results indicate that, during the Omicron wave, the protection of older persons against a severe COVID-19 course gradually declined from six months after vaccination onward. The limitations of this study include confounders that could not be taken into account, possible misclassification of the cause of death, and selection bias due to missing information about vaccination status and severe COVID-19 courses.
Topics: Humans; Aged; Aged, 80 and over; COVID-19; Vaccination; Cluster Analysis; Germany; Hospitalization
PubMed: 37963066
DOI: 10.3238/arztebl.m2023.0230 -
Frontiers in Endocrinology 2023Complete resection of the tumor and the ipsilateral thyroid lobe at the primary surgery is the "gold standard" for the treatment of parathyroid carcinoma (PC). However,... (Comparative Study)
Comparative Study
BACKGROUND
Complete resection of the tumor and the ipsilateral thyroid lobe at the primary surgery is the "gold standard" for the treatment of parathyroid carcinoma (PC). However, differences in the overall survival (OS) of patients with PC who underwent partial and total surgical resection remain to be determined.
METHODS
Data on patients with PC who underwent partial and total surgical resection were extracted from the Surveillance, Epidemiology and End Results (SEER) database (2000-2018). The X-tile software (https://medicine.yale.edu/lab/rimm/research/software/) was used to define the optimal cut-off values for continuous variables. The inverse probability of treatment weighting (IPTW) method was used to reduce the selection bias. IPTW-adjusted Kaplan-Meier curves and Cox proportional hazards models were used to compare the OS of patients with PC in the partial and total surgical resection groups.
RESULTS
A total of 334 patients with PC were included in this study (183 and 151 in the partial and total surgical resection groups, respectively). The optimal cut-off values for age at diagnosis were 53 and 73 years, respectively, while that for tumor size was 34 mm. In both the Kaplan-Meier analysis and univariable Cox proportional hazards regression analysis before IPTW, the difference in OS between the partial and total surgical resection groups was not statistically significant (p>0.05). These findings were confirmed in the IPTW-adjusted Kaplan-Meier analysis and multivariate Cox proportional hazards regression analysis (p>0.05). Subgroup analysis revealed that total surgical resection was beneficial for OS only in the subgroup with unknown tumor size.
CONCLUSION
There was no significant difference in the prognosis of patients who underwent partial and total surgical resection. This finding may provide a useful reference for the treatment of PC.
Topics: Humans; Kaplan-Meier Estimate; Parathyroid Neoplasms; Probability; Prognosis; Proportional Hazards Models; Male; Female; Middle Aged; Aged
PubMed: 37916151
DOI: 10.3389/fendo.2023.1167508 -
BMJ Mental Health May 2024Hypersexuality (HS) accompanying neurological conditions remains poorly characterized despite profound psychosocial impacts. We aimed to systematically review the...
BACKGROUND
Hypersexuality (HS) accompanying neurological conditions remains poorly characterized despite profound psychosocial impacts. We aimed to systematically review the literature on HS in patients with neurological disorders. We conducted a systematic review to identify studies that reported HS in neurological disorders. HS was defined as a condition characterized by excessive and persistent preoccupation with sexual thoughts, urges, and behaviors that cause significant distress or impairment in personal, social, or occupational functioning. Data on demographics, assessment techniques, associated elements, phenotypic manifestations, and management strategies were also extracted. The final analysis included 79 studies on HS, encompassing 32 662 patients across 81 cohorts with neurological disorders. Parkinson's disease was the most frequently studied condition (55.6%), followed by various types of dementia (12.7%). Questionnaires were the most common assessment approach for evaluating HS, although the techniques varied substantially. Alterations in the dopaminergic pathways have emerged as contributing mechanisms based on the effects of medication cessation. However, standardized treatment protocols still need to be improved, with significant heterogeneity in documented approaches. Critical deficiencies include risks of selection bias in participant sampling, uncontrolled residual confounding factors, and lack of blinded evaluations of reported outcomes. Despite growth in the last decade, research on HS remains limited across neurological conditions, with lingering quality and methodological standardization deficits. Key priorities include advancing assessment tools, elucidating the underlying neurobiology, and formulating management guidelines.
PROSPERO REGISTRATION NUMBER
CRD42017036478.
Topics: Humans; Nervous System Diseases; Sexual Dysfunctions, Psychological; Male; Female; Parkinson Disease; Sexual Behavior
PubMed: 38777563
DOI: 10.1136/bmjment-2024-300998 -
International Journal of Surgery... Dec 2023Current clinical guidelines recommend the removal of at least 12 lymph nodes (LNs) in resectable colorectal cancer (CRC). With advancements in lymphadenectomy...
BACKGROUND
Current clinical guidelines recommend the removal of at least 12 lymph nodes (LNs) in resectable colorectal cancer (CRC). With advancements in lymphadenectomy technologies, the number of retrieved lymph nodes (rLNs) has markedly increased. This study aimed to investigate the lowest number of rLNs in node-negative patients.
MATERIALS AND METHODS
A total of 1103 N0 and 208 N1a stage patients were enrolled in our cohort, while 8503 N0 and 1276 N1a patients from the Surveillance, Epidemiology, and End Results CRC database were included. Propensity score matching and multivariate Cox regression analyses were performed to mitigate the influence of selection bias and control for potential confounding variables.
RESULTS
The median number of rLNs in N0 patients increased from 13.5 (interquartile range [IQR]: 9-18) in 2013 to 17 (IQR: 15-20) in 2019. The restrictive cubic spline illustrated a nonlinear relationship between rLNs and prognosis (nonlinearity, P =0.009), with a threshold ( N =16) influencing clinical outcomes. Patients at either N0 or N1a stage with sufficient rLNs (≥16) demonstrated superior prognoses to those with a limited rLNs (<16). After adjusting for clinical confounders, similar prognoses were observed in N0 limited and N1a adequate populations. Furthermore, Kaplan-Meier curves revealed that N0 limited patients who received chemotherapy exhibited better outcomes than those who did not.
CONCLUSIONS
Among patients with node-negative CRC, it is crucial to remove 16 or more LNs effectively. Fewer than 16 rLNs should be regarded as an independent risk factor, implying the need for adjuvant chemotherapy.
Topics: Humans; Neoplasm Staging; Retrospective Studies; Lymph Nodes; Lymph Node Excision; Prognosis; Colorectal Neoplasms
PubMed: 37755374
DOI: 10.1097/JS9.0000000000000746 -
Journal of the Canadian Association of... Apr 2024Interest in patient and public involvement in research has grown. Medical, health, and social care research has demonstrated several benefits of patient and public... (Review)
Review
BACKGROUND
Interest in patient and public involvement in research has grown. Medical, health, and social care research has demonstrated several benefits of patient and public engagement, such as empowering user input and reducing attrition rates in clinical trials. To date, no study has reviewed patient engagement in inflammatory bowel disease (IBD). We aimed to describe the benefits, challenges, and best practices of patient engagement in IBD research.
METHODS
We performed a systematic search on MEDLINE, EMBASE, and Cochrane for all clinical IBD research studies in which patients were involved in the research process (1946- 2023). Patient input was considered in: (1) study design, (2) study execution, (3) research dissemination, and/or (4) other domains not specified here. Two authors independently screened and extracted data on type of engaged person(s), format of engagement, author-reported benefits, recommendations, and challenges. For each study, we reported the level of patient engagement and study adherence to standardized reporting guidelines.
RESULTS
After screening 9,355 articles, we included 51 for final analysis. IBD patients were most frequently engaged in study design. Patient engagement in IBD research improved recruitment rates and promoted the creation of user-friendly quality-of-life tools. Selection bias and recruitment difficulties were common challenges in the application of patient engagement. Authors recommended continuous patient involvement to address emerging priorities and cognitive interviewing to improve questionnaire clarity.
CONCLUSIONS
Patient engagement represents an important step in promoting patient-centred care. According to study authors, implementing cognitive interviewing techniques, continuous patient involvement, and standardized reporting guidelines may improve future iterations of engagement in IBD.
PubMed: 38596798
DOI: 10.1093/jcag/gwad054 -
Global Change Biology Aug 2023Biodiversity offsetting is a globally influential policy mechanism for reconciling trade-offs between development and biodiversity loss. However, there is little robust...
Biodiversity offsetting is a globally influential policy mechanism for reconciling trade-offs between development and biodiversity loss. However, there is little robust evidence of its effectiveness. We evaluated the outcomes of a jurisdictional offsetting policy (Victoria, Australia). Offsets under Victoria's Native Vegetation Framework (2002-2013) aimed to prevent loss and degradation of remnant vegetation, and generate gains in vegetation extent and quality. We categorised offsets into those with near-complete baseline woody vegetation cover ("avoided loss", 2702 ha) and with incomplete cover ("regeneration", 501 ha), and evaluated impacts on woody vegetation extent from 2008 to 2018. We used two approaches to estimate the counterfactual. First, we used statistical matching on biophysical covariates: a common approach in conservation impact evaluation, but which risks ignoring potentially important psychosocial confounders. Second, we compared changes in offsets with changes in sites that were not offsets for the study duration but were later enrolled as offsets, to partially account for self-selection bias (where landholders enrolling land may have shared characteristics affecting how they manage land). Matching on biophysical covariates, we estimated that regeneration offsets increased woody vegetation extent by 1.9%-3.6%/year more than non-offset sites (138-180 ha from 2008 to 2018) but this effect weakened with the second approach (0.3%-1.9%/year more than non-offset sites; 19-97 ha from 2008 to 2018) and disappeared when a single outlier land parcel was removed. Neither approach detected any impact of avoided loss offsets. We cannot conclusively demonstrate whether the policy goal of 'net gain' (NG) was achieved because of data limitations. However, given our evidence that the majority of increases in woody vegetation extent were not additional (would have happened without the scheme), a NG outcome seems unlikely. The results highlight the importance of considering self-selection bias in the design and evaluation of regulatory biodiversity offsetting policy, and the challenges of conducting robust impact evaluations of jurisdictional biodiversity offsetting policies.
Topics: Conservation of Natural Resources; Biodiversity; Wood; Motivation; Victoria; Ecosystem
PubMed: 37300408
DOI: 10.1111/gcb.16801 -
BJS Open Sep 2023Students must be proficient in surgical skills according to General Medical Council and Royal College of Surgeons of England guidelines. If these skills are not...
BACKGROUND
Students must be proficient in surgical skills according to General Medical Council and Royal College of Surgeons of England guidelines. If these skills are not appropriately taught, there is a risk of an incoming junior workforce with inadequate surgical skills. This paper aimed to review the literature relating to undergraduate teaching of surgical skills in the UK and summarize future suggested training methods.
METHODS
The databases MEDLINE, Embase and SCOPUS were searched, and the existing literature relating to methodology of undergraduate teaching of surgical skills in the UK over the past 10 years was summarized. The Medical Education Research Quality Instrument was used to assess research quality.
RESULTS
A total of 19 papers were included. Cross-sectional evaluations and survey-based studies highlight a clear deficit in surgical skills teaching in the UK. Medical students are currently unable to fulfil their own learning needs and meet requirements set out by the General Medical Council. This lack of surgical teaching appears to negatively affect student desire to pursue a surgical career. The three main themes for improvement are extracurricular surgical skills days, near-peer teaching and simulation. Each method appeared to improve learning, although no studies utilized medium- to long-term follow-up to demonstrate efficacy and there lacks a clear consensus as to the 'standard' of undergraduate surgical skill education. There was also potential for selection bias and response shift bias in many of the studies assessing pre- and postintervention confidence and opinions.
CONCLUSION
There is a concerning lack of surgical skills teaching that has resulted in medical students and junior doctors not having the necessary surgical skills as per General Medical Council guidance and students feel that their own learning needs are not met. This failure to address the learning deficit may be responsible for the fall in surgical competition ratios. While surgical skills teaching must be improved urgently, more robust evidence is required to evaluate the optimal ways of approaching this issue.
Topics: Humans; Cross-Sectional Studies; Education, Medical, Undergraduate; Students; Curriculum; England
PubMed: 37819804
DOI: 10.1093/bjsopen/zrad083 -
European Journal of Obstetrics,... Nov 2023Choroid plexus cysts (CPCs) are incidental findings on ultrasound examination of the fetal brain. It is not known if isolated CPCs are associated with any adverse health...
OBJECTIVES
Choroid plexus cysts (CPCs) are incidental findings on ultrasound examination of the fetal brain. It is not known if isolated CPCs are associated with any adverse health or neurodevelopmental outcomes during the life course. This systematic review aimed to collate and synthesize the evidence on whether or not isolated choroid plexus cysts are associated with an increased risk of adverse health or developmental outcomes during childhood and adolescence.
METHODS
A search strategy was developed specifically for this study and applied to four electronic databases Medline (Ovid), Embase (Ovid), Web of Science, and Google Scholar. Studies were assessed and selected for inclusion if there was a measurement of CPC (including single or multiple; unilateral or bilateral; isolated or presenting alongside other markers) during the antenatal or early neonatal period (<7 days) with follow-up of children and adolescents for health and developmental outcomes measured at any time from age 1 month onwards. Study quality was assessed using the Newcastle-Ottawa Quality Assessment Scale. Due to heterogeneity in the types of outcome measures included and the timing of measurement of outcomes across the studies, it was not possible to pool data across studies and a narrative description of findings was presented.
RESULTS
Eight studies (three cohorts and five case series) met the inclusion criteria. Different methods were used for outcome assessment, such as in-person assessment, parent questionnaires, medical records, and telephone interviews with parents. Six studies measured outcomes only once during the specified duration of follow-up; two studies carried out paediatric reviews of the children several times during follow-up. There were no differences in developmental outcomes or physical health between babies with CPCs reported in the three cohort studies, and no abnormalities were detected in the children that were followed up in four of the five case series studies. Most of the included studies were graded as low quality due to the small sample size, high risk of selection bias, unclear definitions of CPC or lack of a comparison group.
CONCLUSIONS
The studies conducted to date do not provide evidence of adverse physical health outcomes or neurodevelopmental delays in babies with CPCs. However, most of these studies were small and included a narrow range of outcomes. Further research is needed to explore the relative incidence of outcomes such as ASD, ADHD, epilepsy and educational attainment in children with CPCs.
Topics: Infant; Infant, Newborn; Child; Humans; Female; Adolescent; Pregnancy; Choroid Plexus; Cohort Studies; Ultrasonography; Parents; Cysts
PubMed: 37778251
DOI: 10.1016/j.ejogrb.2023.09.013 -
Molecular Biology and Evolution Jan 2024Tree tests like the Kishino-Hasegawa (KH) test and chi-square test suffer a selection bias that tests like the Shimodaira-Hasegawa (SH) test and approximately unbiased...
Tree tests like the Kishino-Hasegawa (KH) test and chi-square test suffer a selection bias that tests like the Shimodaira-Hasegawa (SH) test and approximately unbiased test were intended to correct. We investigate tree-testing performance in the presence of severe selection bias. The SH test is found to be very conservative and, surprisingly, its uncorrected analog, the KH test has low Type I error even in the presence of extreme selection bias, leading to a recommendation that the SH test be abandoned. A chi-square test is found to usually behave well and but to require correction in extreme cases. We show how topology testing procedures can be used to get support values for splits and compare the likelihood-based support values to the approximate likelihood ratio test (aLRT) support values. We find that the aLRT support values are reasonable even in settings with severe selection bias that they were not designed for. We also show how they can be used to construct tests of topologies and, in doing so, point out a multiple comparisons issue that should be considered when looking at support values for splits.
Topics: Likelihood Functions; Phylogeny; Selection Bias
PubMed: 38142434
DOI: 10.1093/molbev/msad280