Modeling robust COVID-19 intensive care unit occupancy thresholds for imposing mitigation to prevent exceeding capacities

In non-pharmaceutical management of COVID-19, occupancy of intensive care units (ICU) is often used as an indicator to inform when to intensify mitigation and thus reduce SARS-CoV-2 transmission, strain on ICUs, and deaths. However, ICU occupancy thresholds at which action should be taken are often selected arbitrarily. We propose a quantitative approach using mathematical modeling to identify ICU occupancy thresholds at which mitigation should be triggered to avoid exceeding the ICU capacity available for COVID-19 patients and demonstrate this approach for the United States city of Chicago. We used a stochastic compartmental model to simulate SARS-CoV-2 transmission and disease progression, including critical cases that would require intensive care. We calibrated the model using daily COVID-19 ICU and hospital census data between March and August 2020. We projected various possible ICU occupancy trajectories from September 2020 to May 2021 with two possible levels of transmission increase and uncertainty in core model parameters. The effect of combined mitigation measures was modeled as a decrease in the transmission rate that took effect when projected ICU occupancy reached a specified threshold. We found that mitigation did not immediately eliminate the risk of exceeding ICU capacity. Delaying action by 7 days increased the probability of exceeding ICU capacity by 10–60% and this increase could not be counteracted by stronger mitigation. Even under modest transmission increase, a threshold occupancy no higher than 60% was required when mitigation reduced the reproductive number Rt to just below 1. At higher transmission increase, a threshold of at most 40% was required with mitigation that reduced Rt below 0.75 within the first two weeks after mitigation. Our analysis demonstrates a quantitative approach for the selection of ICU occupancy thresholds that considers parameter uncertainty and compares relevant mitigation and transmission scenarios. An appropriate threshold will depend on the location, number of ICU beds available for COVID-19, available mitigation options, feasible mitigation strengths, and tolerated durations of intensified mitigation.

Multimodal imaging case series of acute macular neuroretinopathy secondary to COVID-19 infection

Purpose : Understanding of the ocular manifestations of coronavirus disease 2019 (COVID-19) is continuing to develop. While ocular symptoms, chiefly conjunctivitis, have been reported, retinal pathologies have been suggested as a rarer complication and are hypothesized to derive from a combination of the inflammatory and vasculopathic effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Using a retrospective, observational case series design, we describe a series of four eyes in three patients with acute macular neuroretinopathy (AMN) and paracentral acute middle maculopathy (PAMM) associated with COVID-19 illness. Methods : Our practice's electronic medical record (EMR) was retrospectively queried for patients from April 2020 to December 2021 who had been diagnosed with AMN or PAMM and COVID-19 illness. Three patients were identified by this method. Patient demographic information, physical exam, optical coherence tomography (OCT), infrared reflectance (IR), and fluorescein angiography (FA) studies were all used for analysis. Results : Imaging signs of AMN were revealed in four eyes in three female patients, aged 22, 32, and 64 years old, all with confirmed symptomatic COVID-19 corresponding to the start of visual symptoms. The average onset of visual symptoms from COVID-19 illness was 14 days (range 0-56). 4/4 eyes were symptomatic for scotomata. Average logMAR visual acuity was 0.024 (Snellen 20/21, range 0-0.097). 4/4 eyes demonstrated typical findings of AMN: IR imaging with prominent dark petaloid or ovoid parafoveal lesions and corresponding disruption of the ellipsoid zone on OCT (Fig. 1). FA imaging did not show any abnormal fluorescence pattern. Autofluorescence in 1/4 eyes demonstrated hyperautofluorescence corresponding to the abnormal area on IR imaging (Fig. 2). Two month follow-up showed persistent symptoms of scotomata with unchanged findings on follow-up imaging in 100% of cases. Conclusions : This series demonstrates that, although rare, SARS-CoV-2 infection may result in microvasculopathic injuries to the retina, namely AMN and PAMM. (Figure Presented).

We All We Got Urban Black Ecologies of Care and Mutual Aid

Urban ecologies are fraught with inequities, often resulting in humanitarian or charity solutions that emphasize lack rather than communities' self-determination. While these inequities have been widely documented, the COVID-19 pandemic further reveals how these crises are not the sum result of individual failures. Rather, they are systemically produced through policies that harm people. How do Black urban residents contend with the sociohistorical antagonisms between feelings of scarcity (e.g., food and housing insecurity, underemployment, and financial strain) and aspirations for abundance? Using ethnographic encounters in Chicago and Austin we consider how practices of mutual aid are meaningful both spatially and affectively. First, we explore how mutual aid transforms "decaying" urban spaces to meet residents' needs. Second, we explore felt experiences of mutuality in social relationships as distinct from authoritarian, charity-based relationality. Thinking these spatial and affective dimensions collectively, we work toward a framework of Black ecologies of care and mutual aid.

Modeling robust COVID-19 intensive care unit occupancy thresholds for imposing mitigation to prevent exceeding capacities.

In non-pharmaceutical management of COVID-19, occupancy of intensive care units (ICU) is often used as an indicator to inform when to intensify mitigation and thus reduce SARS-CoV-2 transmission, strain on ICUs, and deaths. However, ICU occupancy thresholds at which action should be taken are often selected arbitrarily. We propose a quantitative approach using mathematical modeling to identify ICU occupancy thresholds at which mitigation should be triggered to avoid exceeding the ICU capacity available for COVID-19 patients and demonstrate this approach for the United States city of Chicago. We used a stochastic compartmental model to simulate SARS-CoV-2 transmission and disease progression, including critical cases that would require intensive care. We calibrated the model using daily COVID-19 ICU and hospital census data between March and August 2020. We projected various possible ICU occupancy trajectories from September 2020 to May 2021 with two possible levels of transmission increase and uncertainty in core model parameters. The effect of combined mitigation measures was modeled as a decrease in the transmission rate that took effect when projected ICU occupancy reached a specified threshold. We found that mitigation did not immediately eliminate the risk of exceeding ICU capacity. Delaying action by 7 days increased the probability of exceeding ICU capacity by 10-60% and this increase could not be counteracted by stronger mitigation. Even under modest transmission increase, a threshold occupancy no higher than 60% was required when mitigation reduced the reproductive number Rt to just below 1. At higher transmission increase, a threshold of at most 40% was required with mitigation that reduced Rt below 0.75 within the first two weeks after mitigation. Our analysis demonstrates a quantitative approach for the selection of ICU occupancy thresholds that considers parameter uncertainty and compares relevant mitigation and transmission scenarios. An appropriate threshold will depend on the location, number of ICU beds available for COVID-19, available mitigation options, feasible mitigation strengths, and tolerated durations of intensified mitigation.

Racial disparities in prostate cancer treatment in a multi-institutional regional collaborative

INTRODUCTION AND OBJECTIVE: Minority communities disproportionately shouldered poor COVID-19 outcomes, however the impact of the pandemic on prostate cancer (PCa) surgery is unknown. To that end, we sought to determine the racial impact on PCa care during the first wave of the pandemic. METHODS: Using a multi-institutional collaborative we evaluated practice patterns for Black and White patients with untreated non-metastatic PCa during the initial COVID-19 lockdown (March-May 2020) compared to prior (March-May 2019). Patient and practice characteristics were compared by race using Fisher's exact and Pearson's chi-square to compare categorical variables and Wilcoxon rank sum to evaluate continuous covariates. We determined the covariate-adjusted impact of year and race on surgery, using logistic regression models with a race year interaction term. RESULTS: Among the 647 men with non-metastatic PCa, 269 received care during the pandemic and 378 prior. Surgery was significantly less likely in Black men (1.3% v 25.9%;p<0.001), despite similar COVID-19 risk factors, biopsy Gleason grade group, and comparable surgery rates prior (17.7% vs. 19.1%;p=0.75). Black men had higher PSA (8.8 vs. 7.2 p=0.04) and were younger (38.2% vs. 24.4% <60 yr;p=0.09). Regression results demonstrated an 94% reduced odds of surgery (OR=0.06, 95% CI 0.007-0.43;p=0.006) for Black patients, with no change for White patients (OR=1.41, 95% CI 0.89-2.21;p=0.142), after adjusting for covariates. Changes in surgical volume varied by site (33% increase to complete shutdown), with sites that experienced the largest reduction in cancer surgery, caring for a greater proportion of Black patients (figure). CONCLUSIONS: In a large multi-institutional regional collaborative, odds of prostatectomy declined only among Black patients during the initial wave of the COVID-19 pandemic. While localized prostate cancer does not require immediate treatment, this study illuminates systemic inequities within healthcare. Public health efforts are needed to fully recognize the unintended consequence of diversion of cancer resources to the pandemic in order to develop balanced mitigation strategies as viral rates continue to fluctuate.

Prostate cancer treatment disparities during the COVID-19 pandemic, lessons from a multi-institutional collaborative

Background: Minority communities have been disproportionately affected by COVID-19, however the impact of the pandemic on prostate cancer (PCa) treatment is unknown. To that end, we sought to determine the racial impact on PCa surgery during the first wave of the COVID-19 pandemic. Methods: After receiving institutional review board approval, the Pennsylvania Urologic Regional Collaborative (PURC) database was queried to evaluate practice patterns for Black and White patients with untreated non-metastatic PCa during the initial lockdown of the COVID-19 pandemic (March-May 2020) compared to prior (March-May 2019). PURC is a prospective collaborative, which includes private practice and academic institutions within both urban and rural settings including regional safety-net hospitals. As data entry was likely impacted by the pandemic, we limited our search to only practices that had data entered through June 1, 2020 (5 practice sites). We compared patient and disease characteristics by race using Fisher's exact and Pearson's chi-square to compare categorical variables and Wilcoxon rank sum to evaluate continuous covariates. Patients were stratified by risk factors for severe COVID-19 infection as described by the CDC. We determined the covariate-adjusted impact of year and race on surgery, using logistic regression models with a race∗year interaction term. Results: 647 men with untreated nonmetastatic PCa were identified, 269 during the pandemic and 378 from the year prior. During the pandemic, Black men were significantly less likely to undergo prostatectomy compared to White patients (1.3% v 25.9%;p < 0.001), despite similar COVID-19 risk-factors, biopsy Gleason grade group, and comparable surgery rates prior (17.7% vs. 19.1%;p = 0.75). White men had lower pre-biopsy PSA (7.2 vs. 8.8 vs. p = 0.04) and were older (24.4% vs. 38.2% < 60yr;p = 0.09). The regression model demonstrated an 94% decline in odds of surgery(OR = 0.06 95%CI 0.007-0.43;p = 0.006) for Black patients and increase odds of surgery for White patients (OR = 1.41 95%CI 0.89-2.21;p = 0.142), after adjusting for covariates. Changes in surgical volume varied by site (33% increase to complete shutdown), with sites that experienced the largest reduction in cancer surgery, caring for a greater proportion of Black patients. Conclusions: In a large multi-institutional regional collaborative, odds of PCa surgery declined only among Black patients during the initial wave of the COVID-19 pandemic. While localized prostate cancer does not require immediate treatment, the lessons from this study illuminate systemic inequities within healthcare, likely applicable across oncology. Public health efforts are needed to fully recognize the unintended consequence of diversion of cancer resources to the pandemic in order to develop balanced mitigation strategies as viral rates continue to fluctuate.

Modeling robust COVID-19 intensive care unit occupancy thresholds for imposing mitigation to prevent exceeding capacities (preprint)

In managing COVID-19 with non-pharmaceutical interventions, occupancy of intensive care units (ICU) is often used as an indicator to inform when to intensify mitigation and thus reduce SARS-CoV-2 transmission, strain on ICUs, and deaths. However, ICU occupancy thresholds at which action should be taken are often selected arbitrarily. We propose a quantitative approach using mathematical modeling to identify ICU occupancy thresholds at which mitigation should be triggered to avoid exceeding the ICU capacity available for COVID-19 patients. We used a stochastic compartmental model to simulate SARS-CoV-2 transmission and disease progression, including critical cases that would require intensive care. We calibrated the model for the United States city of Chicago using daily COVID-19 ICU and hospital census data between March and August 2020. We projected ICU occupancies from September to May 2021 under two possible levels of transmission increase. The effect of combined mitigation measures was modeled as a decrease in the transmission rate that took effect when projected ICU occupancy reached a specified threshold. We found that mitigation did not immediately eliminate the risk of exceeding ICU capacity. Delaying action by 7 days increased the probability of exceeding ICU capacity by 10-60% and this increase could not be counteracted by stronger mitigation. Even under modest transmission increase, a threshold occupancy no higher than 60% was required when mitigation reduced the reproductive number Rt to just below 1. At higher transmission increase, a threshold of at most 40% was required with mitigation that reduced Rt below 0.75 within the first two weeks after mitigation. Our analysis demonstrates a quantitative approach for the selection of ICU occupancy thresholds that considers parameter uncertainty and compares relevant mitigation and transmission scenarios. An appropriate threshold will depend on the location, number of ICU beds available for COVID-19, available mitigation options, feasible mitigation strengths, and tolerated durations of intensified mitigation.

Geographic and demographic heterogeneity of SARS-CoV-2 diagnostic testing in Illinois, USA, March to December 2020.

BACKGROUND: Availability of SARS-CoV-2 testing in the United States (U.S.) has fluctuated through the course of the COVID-19 pandemic, including in the U.S. state of Illinois. Despite substantial ramp-up in test volume, access to SARS-CoV-2 testing remains limited, heterogeneous, and insufficient to control spread. METHODS: We compared SARS-CoV-2 testing rates across geographic regions, over time, and by demographic characteristics (i.e., age and racial/ethnic groups) in Illinois during March through December 2020. We compared age-matched case fatality ratios and infection fatality ratios through time to estimate the fraction of SARS-CoV-2 infections that have been detected through diagnostic testing. RESULTS: By the end of 2020, initial geographic differences in testing rates had closed substantially. Case fatality ratios were higher in non-Hispanic Black and Hispanic/Latino populations in Illinois relative to non-Hispanic White populations, suggesting that tests were insufficient to accurately capture the true burden of COVID-19 disease in the minority populations during the initial epidemic wave. While testing disparities decreased during 2020, Hispanic/Latino populations consistently remained the least tested at 1.87 tests per 1000 population per day compared with 2.58 and 2.87 for non-Hispanic Black and non-Hispanic White populations, respectively, at the end of 2020. Despite a large expansion in testing since the beginning of the first wave of the epidemic, we estimated that over half (50-80%) of all SARS-CoV-2 infections were not detected by diagnostic testing and continued to evade surveillance. CONCLUSIONS: Systematic methods for identifying relatively under-tested geographic regions and demographic groups may enable policymakers to regularly monitor and evaluate the shifting landscape of diagnostic testing, allowing officials to prioritize allocation of testing resources to reduce disparities in COVID-19 burden and eventually reduce SARS-CoV-2 transmission.

Geographic and demographic heterogeneity of SARS-CoV-2 diagnostic testing in Illinois, USA, March to December 2020 (preprint)

Background Availability of SARS-CoV-2 testing in the United States (U.S.) has fluctuated through the course of the COVID-19 pandemic, including in the U.S. state of Illinois. Despite substantial ramp-up in test volume, access to SARS-CoV-2 testing remains limited, heterogeneous, and insufficient to control spread. Methods We compared SARS-CoV-2 testing rates across geographic regions, over time, and by demographic characteristics (i.e., age and racial/ethnic groups) in Illinois during March through December 2020. We compared age-matched case fatality ratios and infection fatality ratios through time to estimate the fraction of SARS-CoV-2 infections that have been detected through diagnostic testing. Results By the end of 2020, initial geographic differences in testing rates had closed substantially. Case fatality ratios were higher in non-Hispanic Black and Hispanic/Latino populations in Illinois relative to non-Hispanic White populations, suggesting that tests were insufficient to accurately capture the true burden of COVID-19 disease in the minority populations during the initial epidemic wave. While testing disparities decreased during 2020, Hispanic/Latino populations consistently remained the least tested at 1.87 tests per 1000 population per day compared with 2.58 and 2.87 for non-Hispanic Black and non-Hispanic White populations, respectively, at the end of 2020. Despite a large expansion in testing since the beginning of the first wave of the epidemic, we estimated that over half (50-80%) of all SARS-CoV-2 infections were not detected by diagnostic testing and continued to evade surveillance. Conclusions Systematic methods for identifying relatively under-tested geographic regions and demographic groups may enable policymakers to regularly monitor and evaluate the shifting landscape of diagnostic testing, allowing officials to prioritize allocation of testing resources to reduce disparities in COVID-19 burden and eventually reduce SARS-CoV-2 transmission.