Impact of Two Different Recruitment Procedures (Random vs. Volunteer Selection) on the Results of Seroepidemiological Study (SARS-CoV-2)

Inclusion bias affects common variant discovery and replication in a health-system linked biobank

Electronic Health Records (EHR) -linked biobanks have emerged as promising tools for precision medicine, enabling the integration of clinical and molecular data for individual risk assessment. Association studies performed in biobank studies can connect common genetic variation to clinical phenotypes, such as through the use of polygenic scores (PGS), which are starting to have utility in aiding clinician decision making. However, while biobanks aggregate large amounts of data effectively for such studies, most employ various opt-in consent protocols, and, as a result, are expected to be subject to participation and recruitment biases. The extent to which biases affect genetic analyses in biobanks remains unstudied. In this study, we quantify bias and evaluate its impact on genetic analyses, using the UCLA ATLAS Community Health Initiative as a case study. Our analyses reveal that a wide array of factors, particularly socio-demographic characteristics and healthcare utilization patterns, influence participation, effectively differentiating biobank participants from the broader patient population (AUROC = 0.85, AUPRC = 0.82). Through weighting the sample using inverse probability weights derived from probabilities of enrollment, we replicated 54% more known GWAS variants than models that did not take bias into account (e.g. associations between variants in the PPARG gene and type 2 diabetes). We further show that PGS-Phenome wide associations are affected by the weighting scheme, and suggest associations corroborated by weighted analyses to be more robust. Our results highlight that genetic analyses within biobanks should account for inclusion biases, and suggest inverse probability weighting as a potential approach.

Recruitment, data collection, participation rate, and representativeness of the international cross-sectional PRICOV-19 study across 38 countries

BACKGROUND

Recruitment for surveys has been a great challenge, especially in general practice.

METHODS

Here, we reported recruitment strategies, data collection, participation rates (PR) and representativeness of the PRICOV-19 study, an international comparative, cross-sectional, online survey among general practices (GP practices) in 37 European countries and Israel.

RESULTS

Nine (24%) countries reported a published invitation; 19 (50%) had direct contact with all GPs/GP practices; 19 (50%) contacted a sample of GPs /GP practices; and 7 (18%) used another invitation strategy. The median participation rate was 22% (IQR = 10%, 28%). Multiple invitation strategies (P-value 0.93) and multiple strategies to increase PR (P-value 0.64) were not correlated with the PR. GP practices in (semi-) rural areas, GP practices serving more than 10,000 patients, and group practices were over-represented (P-value < 0.001). There was no significant correlation between the PR and strength of the primary care (PC) system [Spearman's r 0.13, 95% CI (-0.24, 0.46); P-value 0.49]; the COVID-19 morbidity [Spearman's r 0.19, 95% CI (-0.14, 0.49); P-value 0.24], or COVID-19 mortality [Spearman's r 0.19, 95% CI (-0.02, 0.58); P-value 0.06] during the three months before country-specific study commencement.

CONCLUSION

Our main contribution here was to describe the survey recruitment and representativeness of PRICOV-19, an important and novel study.

Can CT-based assessment of lateral malleolus anatomy indicate when and how to perform an intramedullary fixation in distal fibula fractures? An analysis of 150 ankles

PURPOSE

The primary aim was to analyse the lateral malleolus morphology with a focus on the shape of the distal fibula for IM fixation of the fibula in infra- and transsyndesmotic fracture patterns. The secondary aim was to propose a treatment algorithm according to the lateral malleolar anatomy.

METHODS

77 healthy, skeletally mature volunteers underwent CT scanning of the ankle. The fibula medullary canal and its cortical thickness were quantitatively analysed at 4 different levels measured from the fibular tip (1.5 cm, 3.0 cm, 4.5 cm, and 6.0 cm). A geometric classification was proposed, and a decision algorithm was developed. Statistical significance was set at a p-value < 0.05.

RESULTS

The smallest diameter of the medullary canal of the fibula was at 6.0 cm from the tip of the fibula, in 98.2% of the ankles. The distal fibula can be classified into triangular and rectangular type, according to the cortical thickness index (p < 0.0001). In 16.7% ankles, the internal diameter of the fibula at 6.0 cm was equal or narrower than 3.5 mm (p < 0.05).

CONCLUSION

The shape of the distal fibula as evaluated by CT-guided analysis allows for IM osteosynthesis of the lateral malleolus in 83% of individuals. In our study, the smallest diameter of the medullary canal of the fibula was located 6.0 cm from the tip of the lateral malleolus. Coronal CT evaluation is advantageous in indicating which type of IM implant should be used safely for infra- and transsyndesmotic fracture patterns, potentially reducing intraoperative risks.

Factors Affecting COVID-19 Testing Behaviours Among the Population in South Western Nigeria

Objectives: The objective of this study was to assess the factors affecting testing behaviours amongst the population in Ondo and Lagos States.

Methods: A cross-sectional study involving 704 individuals who were considered eligible for COVID-19 testing in 4 local governments in Lagos (307) and Ondo (397) states in Nigeria, was conducted from April-June 2021. Respondents were selected using simple random sampling. A close-ended questionnaire was administered using a digital survey platform known as SurveyCTO. Data were analyzed using R 4.1.0.

Results: In Lagos state, 52.4% were females, 47.2% were males while in Ondo, 55.2% were females, 44.6% were male. Chi-square tests of association revealed that socio demographic factors significantly associated with testing patterns was education level in Lagos, and none in Ondo. Testing behavior associated with testing patterns included awareness of nearby COVID-19 testing centers, internet access, knowledge of preexisting conditions and having another member of the family testing positive at 5% significance level.

Conclusion: Knowledge of pre-existing conditions, knowledge of COVID-19 symptoms, and knowing where to go when having symptoms were significantly associated with testing and willingness to test.

Assessing the burden of COVID-19 in developing countries: systematic review, meta-analysis and public policy implications

INTRODUCTION

The infection fatality rate (IFR) of COVID-19 has been carefully measured and analysed in high-income countries, whereas there has been no systematic analysis of age-specific seroprevalence or IFR for developing countries.

METHODS

We systematically reviewed the literature to identify all COVID-19 serology studies in developing countries that were conducted using representative samples collected by February 2021. For each of the antibody assays used in these serology studies, we identified data on assay characteristics, including the extent of seroreversion over time. We analysed the serology data using a Bayesian model that incorporates conventional sampling uncertainty as well as uncertainties about assay sensitivity and specificity. We then calculated IFRs using individual case reports or aggregated public health updates, including age-specific estimates whenever feasible.

RESULTS

In most locations in developing countries, seroprevalence among older adults was similar to that of younger age cohorts, underscoring the limited capacity that these nations have to protect older age groups.Age-specific IFRs were roughly 2 times higher than in high-income countries. The median value of the population IFR was about 0.5%, similar to that of high-income countries, because disparities in healthcare access were roughly offset by differences in population age structure.

CONCLUSION

The burden of COVID-19 is far higher in developing countries than in high-income countries, reflecting a combination of elevated transmission to middle-aged and older adults as well as limited access to adequate healthcare. These results underscore the critical need to ensure medical equity to populations in developing countries through provision of vaccine doses and effective medications.