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Differences in COVID-19-related death rates between people of white and Asian ancestry may be partly explained by documented ethnic/racial differences in risk for blood clotting and pulmonary thrombotic events, investigators propose.
“Our novel findings demonstrate that COVID-19 is associated with a unique type of blood clotting disorder that is primarily focused within the lungs and which undoubtedly contributes to the high levels of mortality being seen in patients with COVID-19,” said James O’Donnell, MB, PhD, director of the Irish Centre for Vascular Biology at the Royal College of Surgeons in Ireland.
Dr. O’Donnell and colleagues studied pulmonary effects and outcomes of 83 patients admitted to St. James Hospital in Dublin, and found evidence to suggest that the diffuse, bilateral pulmonary inflammation seen in many patients with severe COVID-19 infections may be caused by a pulmonary-specific vasculopathy they label “pulmonary intravascular coagulopathy” (PIC), an entity distinct from disseminated intravascular coagulopathy (DIC).
“Given that thrombotic risk is significantly impacted by race, coupled with the accumulating evidence that coagulopathy is important in COVID-19 pathogenesis, our findings raise the intriguing possibility that pulmonary vasculopathy may contribute to the unexplained differences that are beginning to emerge highlighting racial susceptibility to COVID-19 mortality,” they wrote in a study published online in the British Journal of Haematology.
Study flaws harm conclusions
But critical care specialists who agreed to review and comment on the study for MDedge News said that it has significant flaws that affect the ability to interpret the findings and “undermine the conclusions reached by the authors.”
“The underlying premise of the study is that there are racial and ethnic differences in the development of venous thromboembolism that may explain the racial and ethnic differences in outcomes from COVID-19,” J. Daryl Thornton, MD, MPH, a fellow of the American Thoracic Society and associate professor of pulmonary, critical care, and sleep medicine at Case Western Reserve University, Cleveland, said in an interview. “This is an interesting hypothesis and one that could be easily tested in a well-designed study with sufficient representation from the relevant racial and ethnic groups. However, this study is neither well designed nor does it have sufficient racial and ethnic representation.”
Elliott R. Haut, MD, PhD, associate professor of surgery, anesthesiology and critical care medicine at Johns Hopkins Medicine, Baltimore, said in an interview that the study is “mediocre” and has the feel of a paper rushed to press.
“It talks about their theory that race, ethnicity, have an effect on venous thromboembolism, and that’s a pretty well-known fact. No one’s a hundred percent sure why that is, but certainly there are tons and tons of papers that show that there are groups that are at higher risk than others,” he said. “Their idea that this is caused by this pulmonary inflammation, that is totally a guess; there is no data in this paper to support that.”
Dr. Thornton and Dr. Haut both noted that the authors don’t define how race and ethnicity were determined and whether patients were asked to provide it, and although they mention the racial/ethnic breakdown once, subsequent references are to entire cohort are as “Caucasian.”
They also called into question the value of comparing laboratory data across continents in centers with different testing methods and parameters, especially in a time when the clinical picture changes so rapidly.
Coagulation differences
Dr. O’Donnell and colleagues noted that most studies of COVID-19-associated coagulopathy published to date have been with Chinese patients.
“This is important because race and ethnicity have major effects upon thrombotic risk. In particular, epidemiological studies have shown that the incidence of venous thromboembolism (VTE) is approximately three to fourfold lower in Chinese compared to Caucasian individuals. Conversely, VTE risk is significantly higher in African-Americans compared to Caucasians,” they wrote.
Because of the lower risk of VTE in the Chinese population, thromboprophylaxis with low-molecular-weight heparin (LMWH) or other agents is less frequently used in Chinese hospitals than in hospitals with predominantly non-Asian patients, they noted.
To see whether the were differences in coagulopathy between Chinese and white patients, the researchers enrolled 55 men and 28 women, median age 64, who were admitted to St. James Hospital with COVID-19 infections from March 13 through April 10, 2020. The cohort included 67 patients of white background, 10 of Asian ancestry, 5 of African ethnicity, and 1 of Latino/Hispanic ancestry.
Of the 83 patients, 67 had comorbidities at admission. At the time of the report, 50 patients had fully recovered and were discharged, 20 remained in the hospital, and 13 had died. In all, 50 patients were discharged without needing ICU care, 23 were admitted to the ICU, and 10 required ICU but were deemed “clinically unsuitable” for ICU admission.
Although the patients had normal prothrombin time (PT) and normal activated partial thromboplastin time (APTT), plasma d-dimer levels were significantly elevated and were above the range of normal in two-thirds of patients on admission.
Despite the increased d-dimer levels, however, there was no evidence of DIC as defined by the International Society of Thrombosis and Hemostasis Scientific and Standardization committee (ISTH SSC) guidelines. Platelet counts were in the normal range in 83.1% of patients, and only five had counts less than 100 x 109/L at admission. Fibrinogen levels were also elevated, as were C-reactive protein levels, both likely indicating an acute phase response.
“Thus, despite the fact that thrombotic risk is much higher in Caucasian patients and the significant elevated levels of d-dimers observed, overt DIC as defined according to the ISTH SSC DIC score was present in none of our COVID-19 patients at time of admission. Nevertheless, our data confirm that severe COVID-19 infection is associated with a significant coagulopathy in Caucasian patients that appears to be similar in magnitude to that previously reported in the original Chinese cohorts,” they wrote.
When they compared patients who required ICU admission for ventilator support and those who died with patients who were discharged without needing ICU support, they found that survivors were younger (median age 60.2 vs. 75.2 years), and that more critically ill patients were more likely to have comorbidities.
They also found that patients with abnormal coagulation parameters on admission were significantly more likely to have poor prognosis (P = .018), and that patients in the adverse outcomes group had significantly higher fibrinogen and CRP levels (P = .045 and .0005, respectively).
There was no significant difference in PT between the prognosis groups at admission, but by day 4 and beyond PT was a median of 13.1 vs. 12.5 seconds in the favorable outcomes groups (P = .007), and patients with poor prognosis continued to have significantly higher d-dimer levels. (P = .003)
“Cumulatively, these data support the hypothesis that COVID-19–associated coagulopathy probably contributes to the underlying pulmonary pathogenesis,” the researchers wrote.
They noted that the angiotensin converting enzyme 2 (ACE-2) receptor that COVID-19 uses to enter cells is expressed on both type II pneumocytes and vascular endothelial cells within the lung, suggesting that the coagulopathy may be related to direct pulmonary endothelial cell infection , activation, and/or damage, and to the documented cytokine storm that can affect thrombin generation and fibrin deposition within the lungs.
“In the context of this lung-centric vasculopathy, we hypothesize that the refractory acute respiratory distress syndrome phenotype observed in severe COVID-19 is due to concurrent ‘double-hit’ pathologies targeting both ventilation (V) and perfusion (Q) within the lungs where alveoli and pulmonary microvasculature exist in close anatomical juxtaposition,” they wrote.
The investigators noted that larger randomized trials will be needed to determine whether more aggressive anti-coagulation and/or targeted anti-inflammatory therapies could effectively treated PIC in patients with severe COVID-19.
The study was supported by the Wellcome Trust and the Health Research Board Health Service and the Research and Development Division, Northern Ireland. Dr. O’Donnell disclosed speakers bureau activities, advisory board participation, and research grants from multiple companies. The other doctors had no relevant conflicts of interest to disclose.
SOURCE: Fogarty H et al. Br J Haematol. 2020 Apr 24. doi: 10.1111/bjh.16749.
Differences in COVID-19-related death rates between people of white and Asian ancestry may be partly explained by documented ethnic/racial differences in risk for blood clotting and pulmonary thrombotic events, investigators propose.
“Our novel findings demonstrate that COVID-19 is associated with a unique type of blood clotting disorder that is primarily focused within the lungs and which undoubtedly contributes to the high levels of mortality being seen in patients with COVID-19,” said James O’Donnell, MB, PhD, director of the Irish Centre for Vascular Biology at the Royal College of Surgeons in Ireland.
Dr. O’Donnell and colleagues studied pulmonary effects and outcomes of 83 patients admitted to St. James Hospital in Dublin, and found evidence to suggest that the diffuse, bilateral pulmonary inflammation seen in many patients with severe COVID-19 infections may be caused by a pulmonary-specific vasculopathy they label “pulmonary intravascular coagulopathy” (PIC), an entity distinct from disseminated intravascular coagulopathy (DIC).
“Given that thrombotic risk is significantly impacted by race, coupled with the accumulating evidence that coagulopathy is important in COVID-19 pathogenesis, our findings raise the intriguing possibility that pulmonary vasculopathy may contribute to the unexplained differences that are beginning to emerge highlighting racial susceptibility to COVID-19 mortality,” they wrote in a study published online in the British Journal of Haematology.
Study flaws harm conclusions
But critical care specialists who agreed to review and comment on the study for MDedge News said that it has significant flaws that affect the ability to interpret the findings and “undermine the conclusions reached by the authors.”
“The underlying premise of the study is that there are racial and ethnic differences in the development of venous thromboembolism that may explain the racial and ethnic differences in outcomes from COVID-19,” J. Daryl Thornton, MD, MPH, a fellow of the American Thoracic Society and associate professor of pulmonary, critical care, and sleep medicine at Case Western Reserve University, Cleveland, said in an interview. “This is an interesting hypothesis and one that could be easily tested in a well-designed study with sufficient representation from the relevant racial and ethnic groups. However, this study is neither well designed nor does it have sufficient racial and ethnic representation.”
Elliott R. Haut, MD, PhD, associate professor of surgery, anesthesiology and critical care medicine at Johns Hopkins Medicine, Baltimore, said in an interview that the study is “mediocre” and has the feel of a paper rushed to press.
“It talks about their theory that race, ethnicity, have an effect on venous thromboembolism, and that’s a pretty well-known fact. No one’s a hundred percent sure why that is, but certainly there are tons and tons of papers that show that there are groups that are at higher risk than others,” he said. “Their idea that this is caused by this pulmonary inflammation, that is totally a guess; there is no data in this paper to support that.”
Dr. Thornton and Dr. Haut both noted that the authors don’t define how race and ethnicity were determined and whether patients were asked to provide it, and although they mention the racial/ethnic breakdown once, subsequent references are to entire cohort are as “Caucasian.”
They also called into question the value of comparing laboratory data across continents in centers with different testing methods and parameters, especially in a time when the clinical picture changes so rapidly.
Coagulation differences
Dr. O’Donnell and colleagues noted that most studies of COVID-19-associated coagulopathy published to date have been with Chinese patients.
“This is important because race and ethnicity have major effects upon thrombotic risk. In particular, epidemiological studies have shown that the incidence of venous thromboembolism (VTE) is approximately three to fourfold lower in Chinese compared to Caucasian individuals. Conversely, VTE risk is significantly higher in African-Americans compared to Caucasians,” they wrote.
Because of the lower risk of VTE in the Chinese population, thromboprophylaxis with low-molecular-weight heparin (LMWH) or other agents is less frequently used in Chinese hospitals than in hospitals with predominantly non-Asian patients, they noted.
To see whether the were differences in coagulopathy between Chinese and white patients, the researchers enrolled 55 men and 28 women, median age 64, who were admitted to St. James Hospital with COVID-19 infections from March 13 through April 10, 2020. The cohort included 67 patients of white background, 10 of Asian ancestry, 5 of African ethnicity, and 1 of Latino/Hispanic ancestry.
Of the 83 patients, 67 had comorbidities at admission. At the time of the report, 50 patients had fully recovered and were discharged, 20 remained in the hospital, and 13 had died. In all, 50 patients were discharged without needing ICU care, 23 were admitted to the ICU, and 10 required ICU but were deemed “clinically unsuitable” for ICU admission.
Although the patients had normal prothrombin time (PT) and normal activated partial thromboplastin time (APTT), plasma d-dimer levels were significantly elevated and were above the range of normal in two-thirds of patients on admission.
Despite the increased d-dimer levels, however, there was no evidence of DIC as defined by the International Society of Thrombosis and Hemostasis Scientific and Standardization committee (ISTH SSC) guidelines. Platelet counts were in the normal range in 83.1% of patients, and only five had counts less than 100 x 109/L at admission. Fibrinogen levels were also elevated, as were C-reactive protein levels, both likely indicating an acute phase response.
“Thus, despite the fact that thrombotic risk is much higher in Caucasian patients and the significant elevated levels of d-dimers observed, overt DIC as defined according to the ISTH SSC DIC score was present in none of our COVID-19 patients at time of admission. Nevertheless, our data confirm that severe COVID-19 infection is associated with a significant coagulopathy in Caucasian patients that appears to be similar in magnitude to that previously reported in the original Chinese cohorts,” they wrote.
When they compared patients who required ICU admission for ventilator support and those who died with patients who were discharged without needing ICU support, they found that survivors were younger (median age 60.2 vs. 75.2 years), and that more critically ill patients were more likely to have comorbidities.
They also found that patients with abnormal coagulation parameters on admission were significantly more likely to have poor prognosis (P = .018), and that patients in the adverse outcomes group had significantly higher fibrinogen and CRP levels (P = .045 and .0005, respectively).
There was no significant difference in PT between the prognosis groups at admission, but by day 4 and beyond PT was a median of 13.1 vs. 12.5 seconds in the favorable outcomes groups (P = .007), and patients with poor prognosis continued to have significantly higher d-dimer levels. (P = .003)
“Cumulatively, these data support the hypothesis that COVID-19–associated coagulopathy probably contributes to the underlying pulmonary pathogenesis,” the researchers wrote.
They noted that the angiotensin converting enzyme 2 (ACE-2) receptor that COVID-19 uses to enter cells is expressed on both type II pneumocytes and vascular endothelial cells within the lung, suggesting that the coagulopathy may be related to direct pulmonary endothelial cell infection , activation, and/or damage, and to the documented cytokine storm that can affect thrombin generation and fibrin deposition within the lungs.
“In the context of this lung-centric vasculopathy, we hypothesize that the refractory acute respiratory distress syndrome phenotype observed in severe COVID-19 is due to concurrent ‘double-hit’ pathologies targeting both ventilation (V) and perfusion (Q) within the lungs where alveoli and pulmonary microvasculature exist in close anatomical juxtaposition,” they wrote.
The investigators noted that larger randomized trials will be needed to determine whether more aggressive anti-coagulation and/or targeted anti-inflammatory therapies could effectively treated PIC in patients with severe COVID-19.
The study was supported by the Wellcome Trust and the Health Research Board Health Service and the Research and Development Division, Northern Ireland. Dr. O’Donnell disclosed speakers bureau activities, advisory board participation, and research grants from multiple companies. The other doctors had no relevant conflicts of interest to disclose.
SOURCE: Fogarty H et al. Br J Haematol. 2020 Apr 24. doi: 10.1111/bjh.16749.
Differences in COVID-19-related death rates between people of white and Asian ancestry may be partly explained by documented ethnic/racial differences in risk for blood clotting and pulmonary thrombotic events, investigators propose.
“Our novel findings demonstrate that COVID-19 is associated with a unique type of blood clotting disorder that is primarily focused within the lungs and which undoubtedly contributes to the high levels of mortality being seen in patients with COVID-19,” said James O’Donnell, MB, PhD, director of the Irish Centre for Vascular Biology at the Royal College of Surgeons in Ireland.
Dr. O’Donnell and colleagues studied pulmonary effects and outcomes of 83 patients admitted to St. James Hospital in Dublin, and found evidence to suggest that the diffuse, bilateral pulmonary inflammation seen in many patients with severe COVID-19 infections may be caused by a pulmonary-specific vasculopathy they label “pulmonary intravascular coagulopathy” (PIC), an entity distinct from disseminated intravascular coagulopathy (DIC).
“Given that thrombotic risk is significantly impacted by race, coupled with the accumulating evidence that coagulopathy is important in COVID-19 pathogenesis, our findings raise the intriguing possibility that pulmonary vasculopathy may contribute to the unexplained differences that are beginning to emerge highlighting racial susceptibility to COVID-19 mortality,” they wrote in a study published online in the British Journal of Haematology.
Study flaws harm conclusions
But critical care specialists who agreed to review and comment on the study for MDedge News said that it has significant flaws that affect the ability to interpret the findings and “undermine the conclusions reached by the authors.”
“The underlying premise of the study is that there are racial and ethnic differences in the development of venous thromboembolism that may explain the racial and ethnic differences in outcomes from COVID-19,” J. Daryl Thornton, MD, MPH, a fellow of the American Thoracic Society and associate professor of pulmonary, critical care, and sleep medicine at Case Western Reserve University, Cleveland, said in an interview. “This is an interesting hypothesis and one that could be easily tested in a well-designed study with sufficient representation from the relevant racial and ethnic groups. However, this study is neither well designed nor does it have sufficient racial and ethnic representation.”
Elliott R. Haut, MD, PhD, associate professor of surgery, anesthesiology and critical care medicine at Johns Hopkins Medicine, Baltimore, said in an interview that the study is “mediocre” and has the feel of a paper rushed to press.
“It talks about their theory that race, ethnicity, have an effect on venous thromboembolism, and that’s a pretty well-known fact. No one’s a hundred percent sure why that is, but certainly there are tons and tons of papers that show that there are groups that are at higher risk than others,” he said. “Their idea that this is caused by this pulmonary inflammation, that is totally a guess; there is no data in this paper to support that.”
Dr. Thornton and Dr. Haut both noted that the authors don’t define how race and ethnicity were determined and whether patients were asked to provide it, and although they mention the racial/ethnic breakdown once, subsequent references are to entire cohort are as “Caucasian.”
They also called into question the value of comparing laboratory data across continents in centers with different testing methods and parameters, especially in a time when the clinical picture changes so rapidly.
Coagulation differences
Dr. O’Donnell and colleagues noted that most studies of COVID-19-associated coagulopathy published to date have been with Chinese patients.
“This is important because race and ethnicity have major effects upon thrombotic risk. In particular, epidemiological studies have shown that the incidence of venous thromboembolism (VTE) is approximately three to fourfold lower in Chinese compared to Caucasian individuals. Conversely, VTE risk is significantly higher in African-Americans compared to Caucasians,” they wrote.
Because of the lower risk of VTE in the Chinese population, thromboprophylaxis with low-molecular-weight heparin (LMWH) or other agents is less frequently used in Chinese hospitals than in hospitals with predominantly non-Asian patients, they noted.
To see whether the were differences in coagulopathy between Chinese and white patients, the researchers enrolled 55 men and 28 women, median age 64, who were admitted to St. James Hospital with COVID-19 infections from March 13 through April 10, 2020. The cohort included 67 patients of white background, 10 of Asian ancestry, 5 of African ethnicity, and 1 of Latino/Hispanic ancestry.
Of the 83 patients, 67 had comorbidities at admission. At the time of the report, 50 patients had fully recovered and were discharged, 20 remained in the hospital, and 13 had died. In all, 50 patients were discharged without needing ICU care, 23 were admitted to the ICU, and 10 required ICU but were deemed “clinically unsuitable” for ICU admission.
Although the patients had normal prothrombin time (PT) and normal activated partial thromboplastin time (APTT), plasma d-dimer levels were significantly elevated and were above the range of normal in two-thirds of patients on admission.
Despite the increased d-dimer levels, however, there was no evidence of DIC as defined by the International Society of Thrombosis and Hemostasis Scientific and Standardization committee (ISTH SSC) guidelines. Platelet counts were in the normal range in 83.1% of patients, and only five had counts less than 100 x 109/L at admission. Fibrinogen levels were also elevated, as were C-reactive protein levels, both likely indicating an acute phase response.
“Thus, despite the fact that thrombotic risk is much higher in Caucasian patients and the significant elevated levels of d-dimers observed, overt DIC as defined according to the ISTH SSC DIC score was present in none of our COVID-19 patients at time of admission. Nevertheless, our data confirm that severe COVID-19 infection is associated with a significant coagulopathy in Caucasian patients that appears to be similar in magnitude to that previously reported in the original Chinese cohorts,” they wrote.
When they compared patients who required ICU admission for ventilator support and those who died with patients who were discharged without needing ICU support, they found that survivors were younger (median age 60.2 vs. 75.2 years), and that more critically ill patients were more likely to have comorbidities.
They also found that patients with abnormal coagulation parameters on admission were significantly more likely to have poor prognosis (P = .018), and that patients in the adverse outcomes group had significantly higher fibrinogen and CRP levels (P = .045 and .0005, respectively).
There was no significant difference in PT between the prognosis groups at admission, but by day 4 and beyond PT was a median of 13.1 vs. 12.5 seconds in the favorable outcomes groups (P = .007), and patients with poor prognosis continued to have significantly higher d-dimer levels. (P = .003)
“Cumulatively, these data support the hypothesis that COVID-19–associated coagulopathy probably contributes to the underlying pulmonary pathogenesis,” the researchers wrote.
They noted that the angiotensin converting enzyme 2 (ACE-2) receptor that COVID-19 uses to enter cells is expressed on both type II pneumocytes and vascular endothelial cells within the lung, suggesting that the coagulopathy may be related to direct pulmonary endothelial cell infection , activation, and/or damage, and to the documented cytokine storm that can affect thrombin generation and fibrin deposition within the lungs.
“In the context of this lung-centric vasculopathy, we hypothesize that the refractory acute respiratory distress syndrome phenotype observed in severe COVID-19 is due to concurrent ‘double-hit’ pathologies targeting both ventilation (V) and perfusion (Q) within the lungs where alveoli and pulmonary microvasculature exist in close anatomical juxtaposition,” they wrote.
The investigators noted that larger randomized trials will be needed to determine whether more aggressive anti-coagulation and/or targeted anti-inflammatory therapies could effectively treated PIC in patients with severe COVID-19.
The study was supported by the Wellcome Trust and the Health Research Board Health Service and the Research and Development Division, Northern Ireland. Dr. O’Donnell disclosed speakers bureau activities, advisory board participation, and research grants from multiple companies. The other doctors had no relevant conflicts of interest to disclose.
SOURCE: Fogarty H et al. Br J Haematol. 2020 Apr 24. doi: 10.1111/bjh.16749.
FROM THE BRITISH JOURNAL OF HEMATOLOGY