COVID-19 and Risk of VTE in Ethnically Diverse Populations

Retinal Artery and Vein Occlusion Risks after Coronavirus Disease 2019 or Coronavirus Disease 2019 Vaccination

PURPOSE

To evaluate the incidence of new retinal artery occlusion (RAO) and retinal vein occlusion (RVO) after the diagnosis of coronavirus disease 2019 (COVID-19) or vaccination against COVID-19 and compare the incidences with the population with neither.

DESIGN

Nationwide population-based cohort study.

PARTICIPANTS

From a nationwide population-based cohort, 8 418 590 patients were categorized into control (group 1), COVID-19 infection (group 2), and COVID-19 vaccination (group 3) groups.

METHODS

The cumulative incidence of RAO and RVO was calculated in groups 1, 2, and 3 using the Kaplan-Meier method. We calculated hazard ratios (HRs) and 95% confidence intervals (CIs) based on the Poisson distribution for RAO and RVO according to each group and subgroup using Cox proportional hazards models, with group 1 as the reference. We conducted univariable and multivariable analyses for the risk factors of RAO and RVO according to each subgroup.

MAIN OUTCOME MEASURES

Cumulative incidence and risks of incidence of RAO and RVO from the index date to day 60.

RESULTS

In multivariable analysis, no significant increase in RAO and RVO risks after COVID-19 or COVID-19 vaccination were observed in either men or women. These results were observed consistently across various conditions in sensitivity analyses. In subgroup analysis, individuals who were vaccinated before infection showed no significant increase in RAO or RVO risks in both sexes compared with the control group. In the subgroup analysis of vaccinated patients, the HRs of RAO and RVO for different vaccine types did not show an increase compared with the control group; however, an exception was observed in women who received mRNA-1273 vaccines, who showed a higher RAO HR (4.65; 95% CI, 1.27-17.03; P = 0.021).

CONCLUSIONS

Within 60 days of COVID-19 diagnosis or vaccination, RAO and RVO occurred rarely. We observed no increase in the HR of RVO and RAO relative to COVID-19 or COVID-19 vaccination except for a possible increase in the RAO HR in women who received mRNA-1273, for which the raw incidence was extremely low. Further investigation is required to validate this result.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Postoperative thrombotic events following major surgery in patients with a history of COVID-19: a retrospective cohort analysis of commercially insured beneficiaries in the USA

PURPOSE

We sought to evaluate the synergistic risk of postoperative thrombosis in patients with a history of COVID-19 who undergo major surgery. Major surgery and SARS-CoV-2 infection are independently associated with an increased risk of thrombosis, but the magnitude of additional risk beyond surgery conferred by a COVID-19 history on the development of perioperative thrombotic events has not been clearly elucidated in the literature.

METHODS

We conducted a retrospective cohort study among commercially insured adults in the USA from March 2020 to June 2021 using the Optum Labs Data Warehouse (OLDW), a longitudinal, real-world data asset containing deidentified administrative claims and electronic health records. We compared patients with prior COVID-19 who underwent surgery with control individuals who underwent surgery without a COVID-19 history and with control individuals who did not undergo surgery with and without a COVID-19 history. We assessed the interaction of surgery and previous COVID-19 on perioperative thrombotic events (venous thromboembolism and major adverse cardiovascular events) within 90 days using multivariable logistic regression and interaction analysis.

RESULTS

Two million and two-hundred thousand eligible patients were identified from the OLDW. Patients in the surgical cohorts were older and more medically complex than nonsurgical population controls. After adjusting for confounders, only surgical exposure-not COVID-19 history-remained associated with perioperative thrombotic events (adjusted odds ratio [aOR], 4.07; 95% confidence interval [CI], 3.81 to 4.36). The multiplicative interaction term (aOR, 1.25; 95% CI, 0.96 to 1.61) and the synergy index (0.76; 95% CI, 0.56 to 1.04) suggest minimal effect modification of prior COVID-19 on surgery with regards to overall thrombotic risk.

CONCLUSIONS

We found no evidence of synergistic thrombotic risk from previous COVID-19 in patients who underwent selected major surgery relative to the baseline thrombotic risk from surgery alone.

Incidence and determinants of venous thromboembolism over 90 days in hospitalized and nonhospitalized patients with COVID-19

INTRODUCTION

COVID-19 is associated with an increased risk of venous thromboembolism (VTE), but there is great variation among reported incidence rates. Most previous studies have focused on hospitalized patients with COVID-19, and only a few reports are from population-based registries.

METHODS

We studied the 90-day incidence of VTE, associated risk factors and all-cause mortality in hospitalized and nonhospitalized patients with COVID-19 in a nationwide cohort. Data on hospitalizations and outpatient visits were extracted from two national registries with mandatory reporting linked by a unique national identification number carried by all Norwegian residents. We performed Cox proportional hazards regression to determine risk factors for VTE after infection with SARS-CoV-2.

RESULTS

Our study included 30,495 patients with positive SARS-CoV-2 polymerase chain reaction with a mean (SD) age of 41.9 (17.3) years, and 53% were males. Only 2081 (6.8%) were hospitalized. The 90-day incidence of VTE was 0.3% (95% CI: 0.21-0.33) overall and 2.9% (95% CI: 2.3-3.7) in hospitalized patients. Age (hazard ratio [HR] 1.28 per decade, 95% CI: 1.11-1.48, p < 0.05), history of previous VTE (HR 4.69, 95% CI: 2.34-9.40, p < 0.05), and hospitalization for COVID-19 (HR 23.83, 95% CI: 13.48-42.13, p < 0.05) were associated with risk of VTE.

CONCLUSIONS

The 90-day incidence of VTE in hospitalized and nonhospitalized patients with COVID-19 was in the lower end compared with previous reports, with considerably higher rates in hospitalized than nonhospitalized patients. Risk factors for VTE were consistent with previously reported studies.

Placental Histopathologic Findings of a Large Cohort of Patients With SARS-CoV-2 Infection During Pregnancy

Pregnant individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are at a higher risk for adverse pregnancy outcomes. Previous small cohort studies have shown increased frequency of placental lesions associated with maternal vascular malperfusion, fetal vascular malperfusion, and inflammation among patients with SARS-CoV-2, without controlling for cardiometabolic risk factors among many such patients. We aimed to evaluate whether SARS-CoV-2 infection during pregnancy is independently associated with placental abnormalities when controlling for risk factors that could affect placental histopathology. Retrospective cohort study of placentas from singleton pregnancies in Kaiser Permanente Northern California from March to December 2020. Pathologic findings were compared among those with confirmed cases of SARS-CoV-2 during pregnancy and those without. We examined the association between SARS-CoV-2 infection and categorical placental pathologies, controlling for maternal age, gestational age, prepregnancy body mass index, gestational hypertension, preeclampsia/eclampsia, preexisting diabetes, history of thrombosis, and stillbirth. A total of 2,989 singleton gestation placentas were analyzed, 416 (13%) from pregnancies with SARS-CoV-2 infection and 2,573 (86%) from those without infection. Among placentas from pregnancies with SARS-CoV-2, 54.8% had evidence of inflammation, 27.1% maternal malperfusion abnormality, 20.7% massive perivillous fibrin or chronic villitis, 17.3% villous capillary abnormality, and 15.1% fetal malperfusion. After controlling for risks factors and stratifying interval time between SARS-CoV-2 infection and delivery, no association was found between placental abnormalities and SARS-CoV-2 infection during pregnancy. SARS-CoV-2 infection was not associated with an increased risk of placentally mediated adverse outcomes during pregnancy, compared with placentas sent for other indications, in this large diverse cohort.

Retinal vascular occlusion risks during the COVID-19 pandemic and after SARS-CoV-2 infection

The coronavirus disease 2019 (COVID-19) has been reported to affect vascular networks including the eye. However, evidence on the causal relationship between COVID-19 infection and retinal vascular occlusions remains limited. This study aimed to determine the change in retinal vascular occlusion incidence during COVID-19 era and whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection induces retinal vascular occlusion. Retinal vein occlusion (RVO) and retinal artery occlusion (RAO) incidences during 2018-2019 and 2020-July 2021 were compared, those in confirmed and suspected COVID-19 patients diagnosed from 2020 to January 2021 were calculated, and those in COVID-19 patients during 180 days prior and 180 days after diagnosis were assessed. Additionally, the standardized incidence ratio of RVOs in COVID-19 patients was analyzed. Incidence rates per 100,000 people/year of RVO during 2018-2019 and 2020-2021 was 102.0 and 98.8, respectively. RAO incidence rates during 2018-2019 and 2020-2021 were 11.7 and 12.0, respectively. In both confirmed and suspected COVID-19 patients, the incidence of RVO and RAO did not change significantly from 180 days before to after diagnosis in the adjusted model. RVO incidence slightly decreased while RAO incidence increased during the COVID-19 pandemic. SARS-CoV-2 infection did not significantly increase RVO or RAO incidence.

Predictors of pulmonary embolism in hospitalized patients with COVID-19

BACKGROUND

High venous thromboembolism (VTE) rates have been described in critically ill patients with COVID-19. We hypothesized that specific clinical characteristics may help differentiate hypoxic COVID-19 patients with and without a diagnosed pulmonary embolism (PE).

METHODS

We performed a retrospective observational case-control study of 158 consecutive patients hospitalized in one of four Mount Sinai Hospitals with COVID-19 between March 1 and May 8, 2020, who received a Chest CT Pulmonary Angiogram (CTA) to diagnose a PE. We analyzed demographic, clinical, laboratory, radiological, treatment characteristics, and outcomes in COVID-19 patients with and without PE.

RESULTS

92 patients were negative (CTA-), and 66 patients were positive for PE (CTA+). CTA + had a longer time from symptom onset to admission (7 days vs. 4 days, p = 0.05), higher admission biomarkers, notably D-dimer (6.87 vs. 1.59, p < 0.0001), troponin (0.015 vs. 0.01, p = 0.01), and peak D-dimer (9.26 vs. 3.8, p = 0.0008). Predictors of PE included time from symptom onset to admission (OR = 1.11, 95% CI 1.03-1.20, p = 0.008), and PESI score at the time of CTA (OR = 1.02, 95% CI 1.01-1.04, p = 0.008). Predictors of mortality included age (HR 1.13, 95% CI 1.04-1.22, p = 0.006), chronic anticoagulation (13.81, 95% CI 1.24-154, p = 0.03), and admission ferritin (1.001, 95% CI 1-1.001, p = 0.01).

CONCLUSIONS

In 158 hospitalized COVID-19 patients with respiratory failure evaluated for suspected PE, 40.8% patients had a positive CTA. We identified clinical predictors of PE and mortality from PE, which may help with early identification and reduction of PE-related mortality in patients with COVID-19.

Linking Sepsis with chronic arterial hypertension, diabetes mellitus, and socioeconomic factors in the United States: A scoping review

RATIONALE

Sepsis is a syndrome of life-threatening organ dysfunction caused by a dysregulated host immune response to infection. Social risk factors including location and poverty are associated with sepsis-related disparities. Understanding the social and biological phenotypes linked with the incidence of sepsis is warranted to identify the most at-risk populations. We aim to examine how factors in disadvantage influence health disparities related to sepsis.

METHODS

A scoping review was performed for English-language articles published in the United States from 1990 to 2022 on PubMed, Web of Science, and Scopus. Of the 2064 articles found, 139 met eligibility criteria and were included for review.

RESULTS

There is consistency across the literature of disproportionately higher rates of sepsis incidence, mortality, readmissions, and associated complications, in neighborhoods with socioeconomic disadvantage and significant poverty. Chronic arterial hypertension and diabetes mellitus also occur more frequently in the same geographic distribution as sepsis, suggesting a potential shared pathophysiology.

CONCLUSIONS

The distribution of chronic arterial hypertension, diabetes mellitus, social risk factors associated with socioeconomic disadvantage, and sepsis incidence, are clustered in specific geographical areas and linked by endothelial dysfunction. Such population factors can be utilized to create equitable interventions aimed at mitigating sepsis incidence and sepsis-related disparities.

Assessment of the Risk of Venous Thromboembolism in Nonhospitalized Patients With COVID-19

IMPORTANCE

Patients hospitalized with COVID-19 have higher rates of venous thromboembolism (VTE), but the risk and predictors of VTE among individuals with less severe COVID-19 managed in outpatient settings are less well understood.

OBJECTIVES

To assess the risk of VTE among outpatients with COVID-19 and identify independent predictors of VTE.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted at 2 integrated health care delivery systems in Northern and Southern California. Data for this study were obtained from the Kaiser Permanente Virtual Data Warehouse and electronic health records. Participants included nonhospitalized adults aged 18 years or older with COVID-19 diagnosed between January 1, 2020, and January 31, 2021, with follow-up through February 28, 2021.

EXPOSURES

Patient demographic and clinical characteristics identified from integrated electronic health records.

MAIN OUTCOMES AND MEASURES

The primary outcome was the rate per 100 person-years of diagnosed VTE, which was identified using an algorithm based on encounter diagnosis codes and natural language processing. Multivariable regression using a Fine-Gray subdistribution hazard model was used to identify variables independently associated with VTE risk. Multiple imputation was used to address missing data.

RESULTS

A total of 398 530 outpatients with COVID-19 were identified. The mean (SD) age was 43.8 (15.8) years, 53.7% were women, and 54.3% were of self-reported Hispanic ethnicity. There were 292 (0.1%) VTE events identified over the follow-up period, for an overall rate of 0.26 (95% CI, 0.24-0.30) per 100 person-years. The sharpest increase in VTE risk was observed during the first 30 days after COVID-19 diagnosis (unadjusted rate, 0.58; 95% CI, 0.51-0.67 per 100 person-years vs 0.09; 95% CI, 0.08-0.11 per 100 person-years after 30 days). In multivariable models, the following variables were associated with a higher risk for VTE in the setting of nonhospitalized COVID-19: age 55 to 64 years (HR 1.85 [95% CI, 1.26-2.72]), 65 to 74 years (3.43 [95% CI, 2.18-5.39]), 75 to 84 years (5.46 [95% CI, 3.20-9.34]), greater than or equal to 85 years (6.51 [95% CI, 3.05-13.86]), male gender (1.49 [95% CI, 1.15-1.96]), prior VTE (7.49 [95% CI, 4.29-13.07]), thrombophilia (2.52 [95% CI, 1.04-6.14]), inflammatory bowel disease (2.43 [95% CI, 1.02-5.80]), body mass index 30.0-39.9 (1.57 [95% CI, 1.06-2.34]), and body mass index greater than or equal to 40.0 (3.07 [1.95-4.83]).

CONCLUSIONS AND RELEVANCE

In this cohort study of outpatients with COVID-19, the absolute risk of VTE was low. Several patient-level factors were associated with higher VTE risk; these findings may help identify subsets of patients with COVID-19 who may benefit from more intensive surveillance or VTE preventive strategies.

Association between thromboembolic events and COVID-19 infection within 30 days: a case-control study among a large sample of adult hospitalized patients in the United States, March 2020-June 2021

The association between thromboembolic events (TE) and COVID-19 infection is not completely understood at the population level in the United States. We examined their association using a large US healthcare database. We analyzed data from the Premier Healthcare Database Special COVID-19 Release and conducted a case-control study. The study population consisted of men and non-pregnant women aged ≥ 18 years with (cases) or without (controls) an inpatient ICD-10-CM diagnosis of TE between 3/1/2020 and 6/30/2021. Using multivariable logistic regression, we assessed the association between TE occurrence and COVID-19 diagnosis, adjusting for demographic factors and comorbidities. Among 227,343 cases, 15.2% had a concurrent or prior COVID-19 diagnosis within 30 days of their index TE. Multivariable regression analysis showed a statistically significant association between a COVID-19 diagnosis and TE among cases when compared to controls (adjusted odds ratio [aOR] 1.75, 95% CI 1.72-1.78). The association was more substantial if a COVID-19 diagnosis occurred 1-30 days prior to index hospitalization (aOR 3.00, 95% CI 2.88-3.13) compared to the same encounter as the index hospitalization. Our findings suggest an increased risk of TE among persons within 30 days of being diagnosed COVID-19, highlighting the need for careful consideration of the thrombotic risk among COVID-19 patients, particularly during the first month following diagnosis.

Cardiovascular complications in the Post-Acute COVID-19 syndrome (PACS)

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The presence of stress-related (Takotsubo) cardiomyopathy has also been demonstrated in COVID-19.

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The proposed mechanisms of cardiac damage during the acute phase of COVID-19 include both direct -viral penetration- and indirect routes -hypoxic injury and systemic inflammation.

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SARS-CoV-2 infection, especially in its severe form, is associated with an increased risk for venous thromboembolism (VTE).

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Unfractionated heparin (UFH) is the first-line treatment for hemodynamic instability and emergency reperfusion for PASC.

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Further studies are needed to offer current screening for the occurrence of cardiovascular problems especially myocardial infarction and heart failure in COVID-19 patients.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV 2) or coronavirus disease 2019 (COVID-19) initially surfaced in December 2019 from Wuhan, China, sweeping the world with various strains, forcing the WHO to declare a pandemic epidemic in March 2020. Furthermore, COVID-19 manifests with a wide array of presentations from fever and fatigue to severe respiratory and cardiovascular complications. Post-COVID-19 syndrome is poorly understood affecting COVID-19 survivors at all levels of disease severity. The disease is most associated with post-discharge dyspnea and fatigue. However, other persistent symptoms as chest pains, palpitations, smell, and taste dysfunctions. Patients with high concentrations of CRP and creatinine in the acute phase of Covid-19 are more prone to cardiac sequelae. Therefore, high levels of cardiac-sensitive troponin and hypokalaemia can also be used for risk stratification. Furthermore, Cardiac damage can manifest as myocarditis, pericarditis, rhythm abnormalities. The use of different diagnostic modalities like electrocardiogram (ECG), echocardiogram, and cardiac magnetic resonance imaging (MRI)(CMR) to evaluate the myocardial damage were studied. However, Cardiovascular complications are a common manifestation of PASC, classification of severity of cardiac symptoms and the emergence of CMR as a diagnostic tool needs more evidence.

The association of acute COVID-19 infection with Patient Safety Indicator-12 events in a multisite healthcare system

BACKGROUND

Patient Safety Indicator (PSI)-12, a hospital quality measure designed by Agency for Healthcare Research and Quality (AHRQ) to capture potentially preventable adverse events, captures perioperative venous thromboembolism (VTE). It is unclear how COVID-19 has affected PSI-12 performance.

OBJECTIVE

We sought to compare the cumulative incidence of PSI-12 in patients with and without acute COVID-19 infection.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective cohort study including PSI-12-eligible events at three Mayo Clinic medical centers (4/1/2020-10/5/2021).

EXPOSURE, MAIN OUTCOMES, AND MEASURES

We compared the unadjusted rate and adjusted risk ratio (aRR) for PSI-12 events among patients with and without COVID-19 infection using Fisher's exact χ²  test and the AHRQ risk-adjustment software, respectively. We summarized the clinical outcomes of COVID-19 patients with a PSI-12 event.

RESULTS

Our cohort included 50,400 consecutive hospitalizations. Rates of PSI-12 events were significantly higher among patients with acute COVID-19 infection (8/257 [3.11%; 95% confidence interval {CI}, 1.35%-6.04%]) compared to patients without COVID-19 (210/50,143 [0.42%; 95% CI, 0.36%-0.48%]) with a PSI-12 event during the encounter (p < .001). The risk-adjusted rate of PSI-12 was significantly higher in patients with acute COVID-19 infection (1.50% vs. 0.38%; aRR, 3.90; 95% CI, 2.12-7.17; p < .001). All COVID-19 patients with PSI-12 events had severe disease and 4 died. The most common procedure was tracheostomy (75%); the mean (SD) days from surgical procedure to VTE were 0.12 (7.32) days.

CONCLUSION

Patients with acute COVID-19 infection are at higher risk for PSI-12. The present definition of PSI-12 does not account for COVID-19. This may impact hospitals' quality performance if COVID-19 infection is not accounted for by exclusion or risk adjustment.

Perinatal Complications in Individuals in California With or Without SARS-CoV-2 Infection During Pregnancy

Importance

Additional research from population-based studies is needed to inform the treatment of SARS-CoV-2 infection during pregnancy and to provide health risk information to pregnant individuals.

Objective

To assess the risk of perinatal complications associated with SARS-CoV-2 infection and to describe factors associated with hospitalizations.

Design, Setting, and Participants

This population-based cohort study included 43 886 pregnant individuals with longitudinal electronic health record data from preconception to delivery who delivered at Kaiser Permanente Northern California between March 1, 2020, and March 16, 2021. Individuals with diagnostic codes for COVID-19 that did not have a confirmatory polymerase chain reaction test for SARS-CoV-2 were excluded.

Exposures

SARS-CoV-2 infection detected by polymerase chain reaction test (from 30 days before conception to 7 days after delivery) as a time varying exposure.

Main Outcomes and Measures

Severe maternal morbidity including 21 conditions (eg, acute myocardial infarction, acute renal failure, acute respiratory distress syndrome, and sepsis) that occurred at any time during pregnancy or delivery; preterm birth; pregnancy hypertensive disorders; gestational diabetes; venous thromboembolism (VTE); stillbirth; cesarean delivery; and newborn birth weight and respiratory conditions. Standardized mean differences between individuals with and without SARS-CoV-2 were calculated. Cox proportional hazards regression was used to estimate the hazard ratios (HRs) and 95% CIs for the association between SARS-CoV-2 infection and perinatal complications and hospitalization and to consider the timing of SARS-CoV-2 infection relative to outcomes.

Results

In this study of 43 886 pregnant individuals (mean [SD] age, 30.7 [5.2] years), individuals with a SARS-CoV-2 infection (1332 [3.0%]) were more likely to be younger, Hispanic, multiparous individuals with a higher neighborhood deprivation index and obesity or chronic hypertension. After adjusting for demographic characteristics, comorbidities, and smoking status, individuals with SARS-CoV-2 infection had higher risk for severe maternal morbidity (HR, 2.45; 95% CI, 1.91-3.13), preterm birth (<37 weeks; HR, 2.08; 95% CI, 1.75-2.47), and VTE (HR, 3.08; 95% CI, 1.09-8.74) than individuals without SARS-CoV-2. SARS-CoV-2 infection was also associated with increased risk of medically indicated preterm birth (HR, 2.56; 95% CI, 2.06-3.19); spontaneous preterm birth (HR, 1.61; 95% CI, 1.22-2.13); and early (HR, 2.52; 95% CI, 1.49-4.24), moderate (HR, 2.18; 95% CI, 1.25-3.80), and late (HR, 1.95; 95% CI, 1.61-2.37) preterm birth. Among individuals with SARS-CoV-2 infection, 76 (5.7%) had a hospitalization; pregestational diabetes (HR, 7.03; 95% CI, 2.22-22.2) and Asian or Pacific Islander (HR, 2.33; 95% CI, 1.06-5.11) and Black (HR, 3.14; 95% CI, 1.24-7.93) race and ethnicity were associated with an increased risk of hospitalization.

Conclusions and Relevance

In this cohort study, SARS-CoV-2 infection was associated with increased risk of severe maternal morbidity, preterm birth, and VTE. The study findings inform clinicians and patients about the risk of perinatal complications associated with SARS-CoV-2 infection in pregnancy and support vaccination of pregnant individuals and those planning conception.

Changes in the Incidence of Retinal Vascular Occlusions After COVID-19 Diagnosis

Importance

COVID-19 is associated with systemic vascular damage; however, the risk posed to the retinal vasculature remains incompletely understood.

Objective

To assess if there is a change in the incidence of retinal vascular occlusions after COVID-19 infection.

Design, Setting, and Participants

This cohort study at an integrated health care organization (Kaiser Permanente Southern California) included patients without a history of retinal vascular occlusion who were diagnosed with COVID-19 infection between January 20, 2020, and May 31, 2021. Patients were excluded if they had a history of retinal artery occlusions (RAOs) or retinal vein occlusions (RVOs) more than 6 months before their COVID-19 diagnosis or if they were enrolled in Kaiser Permanente Southern California for less than 6 months before COVID-19 diagnosis.

Exposures

COVID-19 infection.

Main Outcomes and Measures

The change in the average biweekly incidence of new RAOs and RVOs after COVID-19 diagnosis. Adjusted incidence rate ratios (IRRs) were calculated to compare the incidence of retinal vascular occlusions before and after COVID-19 diagnosis after accounting for baseline demographic characteristics, medical history, and hospitalization.

Results

A total of 432 515 patients diagnosed with COVID-19 infection were included in this study. The mean (SD) age was 40.9 (19.2) years, and 231 767 patients (53.6%) were women. Sixteen patients had an RAO (crude incidence rate, 3.00 per 1 000 000 patients), and 65 had an RVO (crude incidence rate, 12.20 per 1 000 000 patients) in the 6 months after COVID-19 diagnosis. The incidence of new RVOs was higher in the 6 months after COVID-19 infection compared with the 6 months before infection after adjusting for age; sex; self-reported race and ethnicity; body mass index; history of diabetes, hypertension, or hyperlipidemia; and hospitalization (adjusted IRR, 1.54; 95% CI, 1.05-2.26; P = .03). There was a smaller increase in the incidence of RAOs after COVID-19 diagnosis (IRR, 1.35; 95% CI, 0.64-2.85; P = .44). The peak incidence of RAOs and RVOs occurred 10 to 12 weeks and 6 to 8 weeks after COVID-19 diagnosis, respectively.

Conclusions and Relevance

The findings of this study suggest that there was an increase in the incidence of RVOs after COVID-19 infection; however, these events remain rare, and in the absence of randomized controls, a cause-and-effect relationship cannot be established. Further large, epidemiologic studies are warranted to better define the association between retinal thromboembolic events and COVID-19 infection.

Clinical features of thrombosis and bleeding in COVID-19

Infection with the SARS-CoV-2 virus, resulting in COVID-19 disease has presented a unique scenario associated with high thrombotic rates. The risk of venous thrombosis is some 3-6 fold higher than for patients admitted to hospital for other indications and for patients who have thrombosis, mortality appears increased. Thrombosis may be a presenting feature of COVID-19. Pulmonary thrombi are the most frequent events, some related to deep vein thrombosis, but also in situ micro- and macrovascular thrombosis. Other venous thromboses include catheter and circuit-associated in patients requiring haemofiltration and ECMO. Arterial thrombosis is less commonly documented, with 3% of ICU patients having major arterial strokes and up to 9% myocardial infarction, which is likely multifactorial. Risk factors for thrombosis above those already documented in hospital settings include duration of COVID-19 symptoms before admission to hospital. Laboratory parameters associated with higher thrombotic risk include higher D-dimer, low fibrinogen and low lymphocyte count, with higher FVIII and von Willebrand factor levels indicative of more severe COVID-19 infection. All patients should receive thromboprophylaxis when admitted with COVID-19 infection, but the dose and length of treatment still remain debated. Treatment for thrombosis remains as per standard VTE guidelines, but adjustments may be required depending on other factors relevant to the patient admission.

American Society of Hematology living guidelines on the use of anticoagulation for thromboprophylaxis in patients with COVID-19: July 2021 update on post-discharge thromboprophylaxis

Background

COVID-19–related acute illness is associated with an increased risk of venous thromboembolism (VTE).

Objective

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in decisions about the use of anticoagulation for thromboprophylaxis in patients with COVID-19 who do not have confirmed or suspected VTE.

Methods

ASH formed a multidisciplinary guideline panel, including 3 patient representatives, and applied strategies to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including performing systematic evidence reviews (up to March 2021). The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the grading of recommendations assessment, development, and evaluation (GRADE) approach to assess evidence and make recommendations, which were subject to public comment.

Results

The panel agreed on 1 additional recommendation. The panel issued a conditional recommendation against the use of outpatient anticoagulant prophylaxis in patients with COVID-19 who are discharged from the hospital and who do not have suspected or confirmed VTE or another indication for anticoagulation.

Conclusions

This recommendation was based on very low certainty in the evidence, underscoring the need for high-quality randomized controlled trials assessing the role of postdischarge thromboprophylaxis. Other key research priorities include better evidence on assessing risk of thrombosis and bleeding outcomes in patients with COVID-19 after hospital discharge.