Matthias Egger

University of Bern | UniBe · Institute of Social and Preventive Medicine

People living with human immunodeficiency virus (PLWH) have significantly increased risk for cardiovascular disease in part due to inflammation and immune dysregulation. Clonal hematopoiesis of indeterminate potential (CHIP), the age-related acquisition and expansion of hematopoietic stem cells due to leukemogenic driver mutations, increases risk f...

Aims. The coronavirus disease 2019 (COVID-19) pandemic and ensuing restrictions have negatively affected the mental health and well-being of the general population, and there is increasing evidence suggesting that lockdowns have led to a disruption of health services. In March 2020, South Africa introduced a lockdown in response to the COVID-19 pan...

We describe the HTN care cascade (prevalence, awareness and treatment) among people living with HIV (PLWH) and HIV-negative adults in urban Zambia and Zimbabwe

Background The use of opioids is increasing globally, but data on opioid use disorder (OUD) in South Africa are scarce. This study examines the incidence of diagnosed OUD, opioid agonist use, and excess mortality among persons with OUD in South Africa’s private healthcare sector. Methods We conducted a cohort study of beneficiaries (≥ 11 years) of...

Background Increasing age, male sex, and pre-existing comorbidities are associated with lower survival from SARS-CoV-2 infection. The interplay between different comorbidities, age, and sex is not fully understood, and it remains unclear if survival decreases linearly with higher ICU occupancy or if there is a threshold beyond which survival falls....

Meta-analysis of randomized controlled trials is generally considered the most reliable source of estimates of relative treatment effects. However, in the last few years, there has been interest in using non-randomized studies to complement evidence from randomized controlled trials. Several meta-analytical models have been proposed to this end. Su...

Aims: In March 2020, South Africa introduced a lockdown in response to the COVID-19 pandemic, entailing the suspension of all non-essential activities and a complete ban of tobacco and alcohol sales. We studied the effect of the lockdown on mental health care utilisation rates in private-sector care in South Africa. Methods: We did an interrupted...

Purpose The South African HIV Cancer Match (SAM) Study is a national cohort of people living with HIV (PLWH). It was created using probabilistic record linkages of routine laboratory records of PLWH retrieved by National Health Laboratory Services (NHLS) and cancer data from the National Cancer Registry. The SAM Study aims to assess the spectrum an...

Tuberculosis (TB) is the leading cause of death among PLHIV and multidrug-resistant-TB (MDR-TB) is associated with high mortality. We examined the management for adult PLHIV coinfected with MDR-TB at ART clinics in lower income countries. Between 2019 and 2020, we conducted a cross-sectional survey at 29 ART clinics in high TB burden countries with...

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advan...

Objective : To estimate the prevalence of NRTI and NNRTI drug resistance mutations in patients failing NNRTI-based ART in Southern Africa. Study design : We conducted a systematic review to identify studies reporting drug resistance mutations among adult people living with HIV (PLWH) who experienced virological failure on first-line NNRTI-based AR...

Introduction: In countries with high HIV prevalence, it is important to understand the cervical cancer (CC) patterns by HIV status to ensure targeted prevention measures. We aimed to determine the factors associated with CC compared to non-infection related cancer in women living in South Africa. Methods: This was a cross-sectional study of wome...

The impact of the COVID-19 pandemic on excess mortality from all causes in 2020 varied across and within European countries. Using data for 2015–2019, we applied Bayesian spatio-temporal models to quantify the expected weekly deaths at the regional level had the pandemic not occurred in England, Greece, Italy, Spain, and Switzerland. With around 30...

Background: Congregate settings, such as healthcare clinics, may play an essential role in Mycobacterium tuberculosis (Mtb) transmission. Using patient and environmental data, we studied transmission at a primary care clinic in South Africa. Methods: We collected patient movements, cough frequency, and clinical data, and measured indoor carbon d...

Evidence on the use and efficacy of medical cannabis for children is limited. We examined clinical and epidemiological characteristics of medical cannabis treatment and caregiver-reported effects in children and adolescents in Switzerland. We collected clinical data from children and adolescents (< 18 years) who received Δ9-tetrahydrocannabinol (TH...

Background People living with HIV (PLWH) are at increased risk of developing cancer. Cancer diagnoses are often incompletely captured at antiretroviral therapy (ART) clinics. Aim To estimate the incidence and explore risk factors of cancer in a cohort of PLWH in Harare using probabilistic record linkage (PRL). Methods We conducted a retrospective...

Background As countries move towards the UNAIDS's 95-95-95 targets and with strong evidence that undetectable equals untransmittable, it is increasingly important to assess whether those with HIV who are receiving antiretroviral therapy (ART) achieve viral suppression. We estimated the proportions of children and adolescents and adults with viral s...

Objectives: To investigate mortality among people hospitalised with covid-19 in Switzerland according to epidemic wave, age, sex, comorbid conditions and intensive care unit (ICU) occupancy. Design: Population-based, national study.Setting: Mandatory surveillance reports from all hospitals in Switzerland. Participants: All 22,648 people who tested...

Background & Aims : Chronic hepatitis B virus (HBV) infection is the main cause of hepatocellular carcinoma (HCC) in sub-Saharan Africa (SSA). In an established cohort of HIV/HBV-coinfected individuals on antiretroviral therapy (ART), we piloted an HCC screening initiative at two outpatient clinics in Lusaka, Zambia. Methods : We performed abdomin...

Background Selective outcome reporting and publication bias threaten the validity of systematic reviews and meta-analyses and can affect clinical decision-making. A rigorous method to evaluate the impact of this bias on the results of network meta-analyses of interventions is lacking. We present a tool to assess the Risk Of Bias due to Missing Evid...

Comparative effectiveness research using network meta-analysis can present a hierarchy of competing treatments, from the most to the least preferable option. However, in published reviews, the research question associated with the hierarchy of multiple interventions is typically not clearly defined. Here we introduce the novel notion of a treatment...

Background Exposure to high doses of ionizing radiation is known to cause cancer. Exposure during childhood is associated with a greater excess relative risk for leukemia and tumors of the central nervous system (CNS) than exposure in later life. Cancer risks associated with low-dose exposure (<100 mSv) are uncertain. We previously investigated the...

Background Prognosis for the occurrence of relapses in individuals with relapsing-remitting multiple sclerosis (RRMS), the most common subtype of multiple sclerosis (MS), could support individualized decisions and disease management and could be helpful for efficiently selecting patients for future randomized clinical trials. There are only three p...

Importance Mendelian randomization (MR) studies use genetic variation associated with modifiable exposures to assess their possible causal relationship with outcomes and aim to reduce potential bias from confounding and reverse causation. Objective To develop the STROBE-MR Statement as a stand-alone extension to the STROBE (Strengthening the Repor...

Mendelian randomisation (MR) studies allow a better understanding of the causal effects of modifiable exposures on health outcomes, but the published evidence is often hampered by inadequate reporting. Reporting guidelines help authors effectively communicate all critical information about what was done and what was found. STROBE-MR (strengthening...

The impact of the COVID-19 pandemic on excess mortality from all causes in 2020 varied across and within European countries. Using data for 2015-2019, we applied Bayesian spatio-temporal models to quantify the expected weekly deaths at the regional level had the pandemic not occurred in England, Greece, Italy, Spain, and Switzerland. With around 30...

Introduction The rise of HIV-1 drug resistance to non-nucleoside reverse-transcriptase inhibitors (NNRTI) threatens antiretroviral therapy's long-term success (ART). NNRTIs will remain an essential drug for the management of HIV-1 due to safety concerns associated with integrase inhibitors. We fitted a dynamic transmission model to historical data...

Objectives To assess the effect of migrant status on treatment outcomes among children living with HIV in Europe. Methods Children aged < 18 years at the start of antiretroviral therapy (ART) in European paediatric HIV observational cohorts where ≥ 5% of children were migrants (defined as born abroad) were included. Three outcomes were considered:...

Objective To determine the spectrum of cancers in adolescents and young adults (AYAs) living with and without HIV in South Africa. Design Cross-sectional study with cancer records provided by the National Cancer Registry (NCR) and HIV records from the National Health Laboratory Service (NHLS). Setting and participants The NHLS is the largest prov...

Aims of the study: Vaccination is regarded as the most promising response to the COVID-19 pandemic. We assessed opinions about COVID-19 vaccination, willingness to be vaccinated, and reasons for vaccination hesitancy among healthcare workers. Methods: We conducted a cross-sectional, web-based survey among 3,793 healthcare workers in December 202...

Objective : To determine whether Treat-All policy impacted laboratory testing practices of antiretroviral therapy (ART) programs in Southern Africa. Study Design and Setting : We used HIV cohort data from Lesotho, Malawi, Mozambique, South Africa, Zambia and Zimbabwe in a regression discontinuity design to estimate changes in pre-ART CD4 testing a...

Background Literature on cancer in adolescents and young adults (AYA; aged 15–24 years) living with HIV is scarce. We studied cancer incidence in AYA living with HIV in South Africa between 2004 and 2014. Methods In this nationwide cohort study, we included individuals between 15 and 24 years old who had at least two HIV-related laboratory measure...

Background: Healthcare workers are more frequently exposed to SARS-CoV-2 than the general population. Little is known about healthcare settings outside of hospitals. We studied the seroprevalence of SARS-CoV-2 among healthcare workers in outpatient facilities and retirement or nursing homes in the Canton of Solothurn, Switzerland in the first wave...

Estimating excess mortality allows quantification of overall pandemic impact. For recent decades, mortality data are easily accessible for most industrialized countries, but only a few countries have continuous data available for longer periods. Since Spain, Sweden, and Switzerland were militarily neutral and not involved in combat during both worl...

Estimating excess mortality allows quantification of overall pandemic impact. For recent decades, mortality data are easily accessible for most industrialized countries, but only a few countries have continuous data available for longer periods. Since Spain, Sweden, and Switzerland were militarily neutral and not involved in combat during both worl...

Objectives Chronic hepatitis C virus (HCV) infection affects the immune system. Whether elimination of HCV with direct-acting antivirals (DAA) restores immunity is unclear. We used mass cytometry to get a broad and in-depth assessment of blood cell populations of patients with chronic HCV prior to and after DAA therapy. Methods Before and 12 weeks...

Introduction: The HIV care cascade examines the attrition of people living with HIV from diagnosis to the use of antiretroviral therapy (ART) and suppression of viral replication. We reviewed the literature from sub-Saharan Africa to assess the definitions used for the different steps in the HIV care cascade. Methods: We searched PubMed, Embase...

Objectives: To describe and compare the characteristics of scholars who reviewed for predatory or legitimate journals in terms of their sociodemographic characteristics and reviewing and publishing behaviour. Design: Linkage of random samples of predatory journals and legitimate journals of the Cabells Scholarly Analytics' journal lists with the...

Background: We studied the incidence of and risk factors for various types of cancers in adolescents and young adults living with HIV (AYALWH) in South Africa between 2004 and 2014. Methods: We included individuals aged 15 to 24 years from the South African HIV Cancer Match study, a large cohort resulting from a linkage between HIV-related laborato...

Background. We defined a cascade of cervical screening to evaluate the number of women living with HIV (WLHIV) achieving each cascade stage at an HIV care and treatment clinic in Zimbabwe. Methods. We included women aged ≥18 years enrolled at the Newlands Clinic in Harare from June 2012 to June 2017 and followed them until June 2018. The cascade co...

Aims of the study: Vaccination is regarded as the most promising response to the COVID-19 pandemic. We assessed opinions towards COVID-19 vaccination, willingness to be vaccinated, and reasons for vaccination hesitancy among health care workers (HCWs). Methods: We conducted a cross-sectional, web-based survey among 3,793 HCWs in December 2020 in th...

Objectives To examine the proportion of people living with HIV who screen positive for common mental disorders (CMD) and the associations between CMD and self-reported adherence to antiretroviral therapy (ART). Setting Sixteen government-funded health facilities in the rural Bikita district of Zimbabwe. Design Cross-sectional study. Participants...

Background The inverse care law states that disadvantaged populations need more health care than advantaged populations but receive less. Gaps in COVID-19-related health care and infection control are not well understood. We aimed to examine inequalities in health in the care cascade from testing for SARS-CoV-2 to COVID-19-related hospitalisation,...

Background The Swiss neighbourhood index of socioeconomic position (Swiss-SEP) was published in 2012, based on neighbourhoods of 50 households and data from the 2000 census on rent, education and occupation of the household head, and crowding. We developed updated Swiss-SEP versions and validated them against income and mortality data.Methods We re...

There is a growing number of older people living with HIV (OPLHIV). While a significant proportion of this population are adults growing into old age with HIV, there are also new infections among OPLHIV. There is a lack of data describing the outcomes of OPLHIV who commenced antiretroviral therapy (ART) after the age of 50 years in sub-Saharan Afri...

Objectives: To examine the proportion of people living with HIV who screen positive for common mental disorders (CMD) and the associations between CMD and self-reported adherence to antiretroviral therapy (ART). Setting: Sixteen government-funded health facilities in the rural Bikita district of Zimbabwe. Design: Cross-sectional study. Participants...

Background Attrition threatens the success of antiretroviral therapy (ART). In this cohort study, we examined outcomes of people living with HIV (PLHIV) lost to follow-up (LTFU) 2014-2017 at ART programs in Southern Africa. Methods We confirmed LTFU (missed appointment for ≥60 or ≥90 days, according to local guidelines) by checking medical records...

Prognosis on the occurrence of relapses in individuals with Relapsing-Remitting Multiple Sclerosis (RRMS), the most common subtype of Multiple Sclerosis (MS), could support individualized decisions and disease management and could be helpful for efficiently selecting patients in future randomized clinical trials. There are only three previously pub...

Background: Evidence on use and efficacy of medical cannabis for children is limited. We examined clinical and epidemiological characteristics of medical cannabis treatment and caregiver-reported effects in children and adolescents in Switzerland. Methods: We collected clinical data from children and adolescents (<18 years) who received Δ9-tetrahyd...

Objectives: To trial a simplified, time and cost-saving method for remote evaluation of fellowship applications and compare this with existing panel review processes by analysing concordance between funding decisions, and the use of a lottery-based decision method for proposals of similar quality. Design: The study involved 134 junior fellowship...

Treatment effects vary across different patients, and estimation of this variability is essential for clinical decision‐making. We aimed to develop a model estimating the benefit of alternative treatment options for individual patients, extending a risk modeling approach in a network meta‐analysis framework. We propose a two‐stage prediction model...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

This paper reports survey findings on the Swiss public’s willingness, attitudes, and concerns regarding personalized health research participation by providing health information and biological material. The survey reached a sample of 15,106 Swiss residents, from which we received 5,156 responses (34.1% response rate). The majority of respondents w...

Background Drug resistance threatens global tuberculosis control. We aimed to examine mortality in patients with tuberculosis from high-burden countries, according to concordance or discordance of results from drug susceptibility testing done locally and whole-genome sequencing (WGS). Methods In this multicentre cohort study, we collected pulmonar...

Background: Privacy-preserving probabilistic record linkage (PPPRL) methods were developed and applied in high-income countries to link records within and between organizations under strict privacy protections. PPPRL has not yet been used in African settings.Methods: We used HIV-related laboratory records from National Health Laboratory Services (N...

Background The World Health Organization’s Treat-All guidance recommends CD4 testing prior to antiretroviral treatment (ART) initiation, and routine viral load (VL) monitoring (over CD4 monitoring) for patients on ART. Methods We used regression discontinuity analyses to estimate changes in CD4 testing and VL monitoring among 547,837 ART-naïve pat...

Funding agencies rely on peer review and expert panels to select the research deserving funding. Peer review has limitations, including bias against risky proposals or interdisciplinary research. The inter-rater reliability between reviewers and panels is low, particularly for proposals near the funding line. Funding agencies are increasingly ackno...

Background: We analysed associations between immunodeficiency and cancer incidence in a nationwide cohort of people living with the human immunodeficiency virus (HIV) in South Africa. Methods: We used data from the South African HIV Cancer Match study built on HIV-related laboratory measurements from the National Health Laboratory Services and c...

Objectives We studied time trends in seasonal influenza vaccination and associations with socioeconomic and health-related determinants in Switzerland, overall and in people aged ≥65 years. Design Three cross-sectional surveys. Participants Individuals who participated in the Swiss Health Surveys 2007, 2012 and 2017. We calculated the proportion...

Dose–response models express the effect of different dose or exposure levels on a specific outcome. In meta-analysis, where aggregated-level data is available, dose–response evidence is synthesized using either one-stage or two-stage models in a frequentist setting. We propose a hierarchical dose–response model implemented in a Bayesian framework....

Meta‐analysis of individual patient data (IPD) is increasingly used to synthesize data from multiple trials. IPD meta‐analysis offers several advantages over meta‐analyzing aggregate data, including the capacity to individualize treatment recommendations. Trials usually collect information on many patient characteristics. Some of these covariates m...