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Katy J.L. Bell

Bio: Katy J.L. Bell is an academic researcher from University of Sydney. The author has contributed to research in topics: Medicine & Overdiagnosis. The author has an hindex of 22, co-authored 106 publications receiving 1895 citations. Previous affiliations of Katy J.L. Bell include Bond University & Westmead Hospital.


Papers
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Journal ArticleDOI
11 Dec 2020
TL;DR: This work synthesizes all known cases of true asymptomatic coronavirus disease 2019 (COVID-19) and aims to synthesize all known avian influenza A viruses to help design mitigation measures against the pandemic.
Abstract: Background: Knowing the prevalence of true asymptomatic coronavirus disease 2019 (COVID-19) cases is critical for designing mitigation measures against the pandemic. We aimed to synthesize all avai...

532 citations

Journal ArticleDOI
TL;DR: There is a substantial reservoir of incidental prostate cancer which increases with age, and the high risk of overdiagnosis limits the usefulness of prostate cancer screening.
Abstract: Prostate cancer screening may detect nonprogressive cancers, leading to overdiagnosis and overtreatment. The potential for overdiagnosis can be assessed from the reservoir of prostate cancer in autopsy studies that report incidental prostate cancer rates in men who died of other causes. We aimed to estimate the age-specific incidental cancer prevalence from all published autopsy studies. We identified eligible studies by searches of Medline and Embase, forward and backward citation searches and contacting authors. We screened the titles and abstracts of all articles; checked the full-text articles for eligibility and extracted clinical and pathology data using standardized forms. We extracted mean cancer prevalence, age-specific cancer prevalence and validity measures and then pooled data from all studies using logistic regression models with random effects. The 29 studies included in the review dated from 1948 to 2013. Incidental cancer was detected in all populations, with no obvious time trends in prevalence. Prostate cancer prevalence increased with each decade of age, OR 51.7 (1.6–1.8), and was higher in studies that used the Gleason score, OR 52.0 (1.1–3.7). No other factors were significantly predictive. The estimated mean cancer prevalence increased in a nonlinear fashion from 5% (95% CI: 3–8%) at age 79 years. There was substantial variation between populations in estimated cancer prevalence. There is a substantial reservoir of incidental prostate cancer which increases with age. The high risk of overdiagnosis limits the usefulness of prostate cancer screening.

291 citations

Journal ArticleDOI
TL;DR: It is confirmed that iDTC is common, but the observed increasing incidence is not mirrored by prevalence within autopsy studies and, therefore, is unlikely to reflect a true population-level increase in tumorigenesis.
Abstract: PurposeDifferentiated thyroid cancer (DTC) incidence has been reported to have increased three- to 15-fold in the past few decades. It is unclear whether this represents overdiagnosis or a true increase in incidence. Therefore, the current study aimed to estimate the prevalence of incidental DTC in published autopsy series and determine whether this prevalence has been increasing over time.Materials and MethodsPubMed, Embase, and Web of Science were searched from inception to December 2015 for relevant studies. Two authors searched for all autopsy studies that had included patients with no known history of thyroid pathology and reported the prevalence of incidental DTC (iDTC). Two authors independently extracted the data, and discrepancies were resolved by another author. The pooled prevalence of iDTC was assessed using a fixed-effects meta-analysis model with robust error variance. The time effect was studied using an inverse-variance weighted logit-linear regression model with robust error variance and ...

149 citations

Posted ContentDOI
04 Jun 2020-medRxiv
TL;DR: Estimates of the prevalence of asymptomatic COVID-19 cases are lower than many highly publicized studies, but still substantial; further robust epidemiological evidence is urgently needed, including in sub-populations such as children, to better understand the importance of asylptomatic cases for driving spread of the pandemic.
Abstract: Background The prevalence of true asymptomatic COVID-19 cases is critical to policy makers considering the effectiveness of mitigation measures against the SARS-CoV-2 pandemic. We aimed to synthesize all available research on the asymptomatic rates and transmission rates where possible. Methods We searched PubMed, Embase, Cochrane COVID-19 trials, and Europe PMC (which covers pre-print platforms such as MedRxiv). We included primary studies reporting on asymptomatic prevalence where: (a) the sample frame includes at-risk population, and (b) there was sufficiently long follow up to identify pre-symptomatic cases. Meta-analysis used fixed effect and random effects models. We assessed risk of bias by combination of questions adapted from risk of bias tools for prevalence and diagnostic accuracy studies. Results We screened 998 articles and included nine low risk-of-bias studies from six countries that tested 21,035 at-risk people, of which 559 were positive and 83 were asymptomatic. Diagnosis in all studies was confirmed using a RT-qPCR test. The proportion of asymptomatic cases ranged from 4% to 41%. Meta-analysis (fixed effect) found that the proportion of asymptomatic cases was 15% (95% CI: 12% - 18%) overall; higher in non-aged care 16% (13% - 19%), and lower in long-term aged care 8% (3% - 18%). Four studies provided direct evidence of forward transmission of the infection by asymptomatic cases but suggested considerably lower rates than symptomatic cases. Discussion Our estimates of the prevalence of asymptomatic COVID-19 cases and asymptomatic transmission rates are lower than many highly publicized studies, but still sufficient to warrant policy attention. Further robust epidemiological evidence is urgently needed, including in sub-populations such as children, to better understand the importance of asymptomatic cases for driving spread of the pandemic. Funding OB is supported by NHMRC Grant APP1106452. PG is supported by NHMRC Australian Fellowship grant 1080042. KB was supported by NHMRC Fellowship grant 1174523. All authors had full access to all data and agreed to final manuscript to be submitted for publication. There was no funding source for this study.

133 citations

Journal ArticleDOI
01 Jun 2019-BMJ Open
TL;DR: Lung function—FEV1, FVC and PEFR—decline with age in individuals without known lung disease, and the definition of chronic airway disease may need to be reconsidered to allow for normal ageing.
Abstract: Objective To conduct a systematic review investigating the normal age-related changes in lung function in adults without known lung disease. Design Systematic review. Data sources MEDLINE, Embase and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were searched for eligible studies from inception to February 12, 2019, supplemented by manual searches of reference lists and clinical trial registries. Eligibility criteria We planned to include prospective cohort studies and randomised controlled trials (control arms) that measured changes in lung function over time in asymptomatic adults without known respiratory disease. Data extraction and synthesis Two authors independently determined the eligibility of studies, extracted data and assessed the risk of bias of included studies using the modified Newcastle–Ottawa Scale. Results From 4385 records screened, we identified 16 cohort studies with 31 099 participants. All included studies demonstrated decline in lung function—forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) with age. In studies with longer follow-up (>10 years), rates of FEV1 decline ranged from 17.7 to 46.4 mL/year (median 22.4 mL/year). Overall, men had faster absolute rates of decline (median 43.5 mL/year) compared with women (median 30.5 mL/year). Differences in relative FEV1 change, however, were not observed between men and women. FEV1/FVC change was reported in only one study, declining by 0.29% per year. An age-specific analysis suggested the rate of FEV1 function decline may accelerate with each decade of age. Conclusions Lung function—FEV1, FVC and PEFR—decline with age in individuals without known lung disease. The definition of chronic airway disease may need to be reconsidered to allow for normal ageing and ensure that people likely to benefit from interventions are identified rather than healthy people who may be harmed by potential overdiagnosis and overtreatment. The first step would be to apply age, sex and ethnicity-adjusted FEV1/FVC thresholds to the disease definition of chronic obstructive pulmonary disease. PROSPERO registration number CRD42018087066.

102 citations


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Journal ArticleDOI
TL;DR: The GLOBOCAN 2020 estimates of cancer incidence and mortality produced by the International Agency for Research on Cancer (IARC) as mentioned in this paper show that female breast cancer has surpassed lung cancer as the most commonly diagnosed cancer, with an estimated 2.3 million new cases (11.7%), followed by lung cancer, colorectal (11 4.4%), liver (8.3%), stomach (7.7%) and female breast (6.9%), and cervical cancer (5.6%) cancers.
Abstract: This article provides an update on the global cancer burden using the GLOBOCAN 2020 estimates of cancer incidence and mortality produced by the International Agency for Research on Cancer. Worldwide, an estimated 19.3 million new cancer cases (18.1 million excluding nonmelanoma skin cancer) and almost 10.0 million cancer deaths (9.9 million excluding nonmelanoma skin cancer) occurred in 2020. Female breast cancer has surpassed lung cancer as the most commonly diagnosed cancer, with an estimated 2.3 million new cases (11.7%), followed by lung (11.4%), colorectal (10.0 %), prostate (7.3%), and stomach (5.6%) cancers. Lung cancer remained the leading cause of cancer death, with an estimated 1.8 million deaths (18%), followed by colorectal (9.4%), liver (8.3%), stomach (7.7%), and female breast (6.9%) cancers. Overall incidence was from 2-fold to 3-fold higher in transitioned versus transitioning countries for both sexes, whereas mortality varied <2-fold for men and little for women. Death rates for female breast and cervical cancers, however, were considerably higher in transitioning versus transitioned countries (15.0 vs 12.8 per 100,000 and 12.4 vs 5.2 per 100,000, respectively). The global cancer burden is expected to be 28.4 million cases in 2040, a 47% rise from 2020, with a larger increase in transitioning (64% to 95%) versus transitioned (32% to 56%) countries due to demographic changes, although this may be further exacerbated by increasing risk factors associated with globalization and a growing economy. Efforts to build a sustainable infrastructure for the dissemination of cancer prevention measures and provision of cancer care in transitioning countries is critical for global cancer control.

35,190 citations

Journal ArticleDOI
TL;DR: Progress has stagnated for breast and prostate cancers but strengthened for lung cancer, coinciding with changes in medical practice related to cancer screening and/or treatment, and mortality patterns reflect incidence trends.
Abstract: Each year, the American Cancer Society estimates the numbers of new cancer cases and deaths in the United States and compiles the most recent data on population‐based cancer occurrence and outcomes. Incidence data (through 2018) were collected by the Surveillance, Epidemiology, and End Results program; the National Program of Cancer Registries; and the North American Association of Central Cancer Registries. Mortality data (through 2019) were collected by the National Center for Health Statistics. In 2022, 1,918,030 new cancer cases and 609,360 cancer deaths are projected to occur in the United States, including approximately 350 deaths per day from lung cancer, the leading cause of cancer death. Incidence during 2014 through 2018 continued a slow increase for female breast cancer (by 0.5% annually) and remained stable for prostate cancer, despite a 4% to 6% annual increase for advanced disease since 2011. Consequently, the proportion of prostate cancer diagnosed at a distant stage increased from 3.9% to 8.2% over the past decade. In contrast, lung cancer incidence continued to decline steeply for advanced disease while rates for localized‐stage increased suddenly by 4.5% annually, contributing to gains both in the proportion of localized‐stage diagnoses (from 17% in 2004 to 28% in 2018) and 3‐year relative survival (from 21% to 31%). Mortality patterns reflect incidence trends, with declines accelerating for lung cancer, slowing for breast cancer, and stabilizing for prostate cancer. In summary, progress has stagnated for breast and prostate cancers but strengthened for lung cancer, coinciding with changes in medical practice related to cancer screening and/or treatment. More targeted cancer control interventions and investment in improved early detection and treatment would facilitate reductions in cancer mortality.

7,115 citations

Journal ArticleDOI
25 Aug 2020-JAMA
TL;DR: This review discusses current evidence regarding the pathophysiology, transmission, diagnosis, and management of COVID-19, the novel severe acute respiratory syndrome coronavirus 2 pandemic that has caused a worldwide sudden and substantial increase in hospitalizations for pneumonia with multiorgan disease.
Abstract: Importance The coronavirus disease 2019 (COVID-19) pandemic, due to the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has caused a worldwide sudden and substantial increase in hospitalizations for pneumonia with multiorgan disease. This review discusses current evidence regarding the pathophysiology, transmission, diagnosis, and management of COVID-19. Observations SARS-CoV-2 is spread primarily via respiratory droplets during close face-to-face contact. Infection can be spread by asymptomatic, presymptomatic, and symptomatic carriers. The average time from exposure to symptom onset is 5 days, and 97.5% of people who develop symptoms do so within 11.5 days. The most common symptoms are fever, dry cough, and shortness of breath. Radiographic and laboratory abnormalities, such as lymphopenia and elevated lactate dehydrogenase, are common, but nonspecific. Diagnosis is made by detection of SARS-CoV-2 via reverse transcription polymerase chain reaction testing, although false-negative test results may occur in up to 20% to 67% of patients; however, this is dependent on the quality and timing of testing. Manifestations of COVID-19 include asymptomatic carriers and fulminant disease characterized by sepsis and acute respiratory failure. Approximately 5% of patients with COVID-19, and 20% of those hospitalized, experience severe symptoms necessitating intensive care. More than 75% of patients hospitalized with COVID-19 require supplemental oxygen. Treatment for individuals with COVID-19 includes best practices for supportive management of acute hypoxic respiratory failure. Emerging data indicate that dexamethasone therapy reduces 28-day mortality in patients requiring supplemental oxygen compared with usual care (21.6% vs 24.6%; age-adjusted rate ratio, 0.83 [95% CI, 0.74-0.92]) and that remdesivir improves time to recovery (hospital discharge or no supplemental oxygen requirement) from 15 to 11 days. In a randomized trial of 103 patients with COVID-19, convalescent plasma did not shorten time to recovery. Ongoing trials are testing antiviral therapies, immune modulators, and anticoagulants. The case-fatality rate for COVID-19 varies markedly by age, ranging from 0.3 deaths per 1000 cases among patients aged 5 to 17 years to 304.9 deaths per 1000 cases among patients aged 85 years or older in the US. Among patients hospitalized in the intensive care unit, the case fatality is up to 40%. At least 120 SARS-CoV-2 vaccines are under development. Until an effective vaccine is available, the primary methods to reduce spread are face masks, social distancing, and contact tracing. Monoclonal antibodies and hyperimmune globulin may provide additional preventive strategies. Conclusions and Relevance As of July 1, 2020, more than 10 million people worldwide had been infected with SARS-CoV-2. Many aspects of transmission, infection, and treatment remain unclear. Advances in prevention and effective management of COVID-19 will require basic and clinical investigation and public health and clinical interventions.

3,371 citations

Journal ArticleDOI
TL;DR: In spite of the high social and economic cost of osteoporosis, a substantial treatment gap and projected increase of the economic burden driven by the aging populations, the use of pharmacological interventions to prevent fractures has decreased in recent years, suggesting that a change in healthcare policy is warranted.
Abstract: Summary This report describes the epidemiology, burden, and treatment of osteoporosis in the 27 countries of the European Union (EU27).

2,016 citations

Journal ArticleDOI
Marina Pollán1, Beatriz Pérez-Gómez1, Roberto Pastor-Barriuso1, Jesús Oteo1, Miguel A. Hernán2, Miguel A. Hernán3, Mayte Pérez-Olmeda1, Jose L Sanmartín, Aurora Fernández-García1, Aurora Fernández-García4, Israel Cruz1, Nerea Fernández de Larrea1, Marta Molina, Francisco Rodríguez-Cabrera1, Mariano Martín, Paloma Merino-Amador4, Jose León Paniagua1, Juan F Muñoz-Montalvo, Faustino Blanco, Raquel Yotti1, Rodrigo Gutiérrez Fernández, Saturnino Mezcua Navarro, Matías Salinero Hernández, Manuel Cuenca-Estrella, Pablo Fernández-Navarro, Ana Avellón, Giovanni Fedele, Jesús Oteo Iglesias, María Teresa Pérez Olmeda, Maria Elena Martinez, Francisco D. Rodríguez-Cabrera1, Susana Padrones Fernández, José Manuel Rumbao Aguirre, José M. Navarro Marí, Begoña Palop Borrás, Ana Belén Pérez Jiménez, Manuel Rodríguez-Iglesias, Ana María Calvo Gascón, María Luz Lou Alcaine, Ignacio Donate Suárez, Oscar Suárez Álvarez, Mercedes Rodríguez Pérez, Margarita Cases Sanchís, Carlos Javier Villafáfila Gomila, Lluis Carbo Saladrigas, Adoración Hurtado Fernández, Antonio Oliver, Elías Castro Feliciano, María Noemí González Quintana, José María Barrasa Fernández, María Araceli Hernández Betancor, Melisa Hernández Febles, Leopoldo Martín Martín, Luis-Mariano López López, Teresa Ugarte Miota, Inés De Benito Población, María Sagrario Celada Pérez, María Natalia Vallés Fernández, Tomás Maté Enríquez, Miguel Villa Arranz, Marta Domínguez-Gil González, Isabel Fernández-Natal, Gregoria Megías Lobón, Juan Luis Muñoz Bellido, Pilar Ciruela, Ariadna Mas i Casals, Maria Doladé Botías, M. Angeles Marcos Maeso, Dúnia Pérez del Campo, Antonio Félix de Castro, Ramón Limón Ramírez, Maria Francisca Elías Retamosa, Manuela Rubio González, María Sinda Blanco Lobeiras, Alberto Fuentes Losada, Antonio Aguilera, Germán Bou, Yolanda Caro, Noemí Marauri, Luis Miguel Soria Blanco, Isabel González, Montserrat Hernández Pascual, Roberto Alonso Fernández, Natalia Cabrera Castro, Aurora Tomás Lizcano, Cristóbal Ramírez Almagro, M. Hernández, Nieves Ascunce Elizaga, María Ederra Sanz, Carmen Ezpeleta Baquedano, Ana Bustinduy Bascaran, Susana Iglesias Tamayo, Luis Elorduy Otazua, Rebeca Benarroch Benarroch, Jesús Lopera Flores, Antonia Vázquez de la Villa 
TL;DR: In this paper, a nationwide population-based study aims to estimate the seroprevalence of SARS-CoV-2 infection in Spain at national and regional level.

1,435 citations