Thrombotic and Hemorrhagic Incidences in Patients After Discharge from COVID-19 Infection: A Systematic Review and Meta-Analysis

Background

The association between coronavirus infection 2019 (COVID-19) and thrombosis has been explicitly shown through numerous reports that demonstrate high rates of thrombotic complications in infected patients. Recently, much evidence has shown that patients who survived COVID-19 might have a high thrombotic risk after hospital discharge. This current systematic review and meta-analysis was conducted to better understand the incidence of thrombosis, bleeding, and mortality rates among patients discharged after COVID-19 hospitalization.

Methods

Using a search strategy that included terms for postdischarge, thrombosis, and COVID-19, 2 investigators independently searched for published articles indexed in the MEDLINE, Embase, and Scopus databases that were published before August 2021. Pooled incidences and 95% confidence intervals were calculated using the DerSimonian-Laird random-effects model with a double arcsine transformation.

Results

Twenty articles were included in the meta-analysis. They provided a total of 19 461 patients discharged after COVID-19 hospitalization. The weighted pooled incidence of overall thrombosis among the patients was 1.3% (95 CI, 0. 6-2; I² 90.5), with a pooled incidence of venous thrombosis of 0.7% (95 CI, 0. 4-1; I² 73.9) and a pooled incidence of arterial thrombosis of 0.6% (95 CI, 0. 2-1; I² 88.1). The weighted pooled incidences of bleeding and mortality were 0.9% (95 CI, 0. 1-1.9; I² 95.1) and 2.8% (95 CI, 0. 6-5; I² 98.2), respectively.

Conclusions

The incidences of thrombosis and bleeding in patients discharged after COVID-19 hospitalization are comparable to those of medically ill patients.

Efficacy and the Adverse Effects of Oral Versus Intravenous Arsenic for Acute Promyelocytic Leukemia: A Meta-Analysis of Randomized-Controlled Studies

Acute promyelocytic leukemia, a subtype of acute myeloid leukemia, is highly curable. In subgroup of patients with non-high-risk acute promyelocytic leukemia, intravenous arsenic trioxide plus all-trans-retinoic acid is considered the preferred regimen for acute promyelocytic leukemia. Recently, there are interests in the use of the oral form of arsenic, named the Realgar-Indigo naturalis formula, but the data on its efficacy and safety are still relatively limited. The current study was conducted with the aims to identify and summarize the results of all available randomized-controlled studies. A systematic review was conducted in the 2 major databases, utilizing the terms for arsenic and acute promyelocytic leukemia. Eligible studies had to be randomized-controlled studies that compared efficacy and/or adverse effects of oral arsenic versus intravenous arsenic for treatment of patients with acute promyelocytic leukemia. The Mantel-Haenszel method was used to pool the effect estimates and 95% confidence intervals of the included studies together. A total of 4 randomized controlled studies with 482 patients with acute promyelocytic leukemia (258 in Realgar-Indigo naturalis formula group and 224 in intravenous arsenic trioxide group) were included in the meta-analysis. The chances of achieving complete remission were numerically higher in the Realgar-Indigo naturalis formula group but the difference was not statistically significant (pooled odds ratio: 4.59, 95% CI: 0.74-28.57, I² = 0%). Similarly, other efficacy outcomes, including 30-day mortality rate, overall survival, and event-free survival, also tended to favor the Realgar-Indigo naturalis formula group but the difference was not statistically significant. There was no significant difference in the chance of developing differentiation syndrome, cardiac complications, grades 3 to 4 liver toxicity, grades 3 to 4 renal toxicity, and infection between the 2 groups. The results may suggest that all-trans-retinoic acid plus oral Realgar-Indigo naturalis formula regimen is, at minimum, not a worse alternative to the standard all-trans-retinoic acid plus intravenous intravenous arsenic trioxide regimen for treatment of acute promyelocytic leukemia, especially for patients with low-to-intermediate risk.

Comparison between optical microscopy and the Sysmex XN-3000 for schistocyte determination in patients suspected of having schistocytosis

Background and aims

Diagnosis of thrombotic microangiopathy (TMA) relies on microscopic schistocyte determination by an experienced microscopist. In addition, schistocytes can be found in non‐TMA–related disorders such as thalassaemia. We aimed to compare the accuracy of the automated haematology analyser Sysmex XN‐3000 for schistocyte detection, to that of the microscopy approach, in patients suspected of having schistocytosis.

Methods

Consecutive blood samples were collected between April 2016 and March 2017 at Siriraj Hospital, Mahidol University, Bangkok, Thailand. Specimens were collected from adults with suspected TMA or with thalassaemia trait and/or disease. All blood samples were examined by both microscopy and the analyser. Samples were considered to be positive for schistocytes (ie, schistocytosis) if they had a schistocyte count ≥1% by microscopy. The analyser's ability to determine schistocytosis was assessed by receiver operating characteristic (ROC) curve. Sensitivity, specificity, positive (PPV), and negative predictive value (NPV) of an appropriate cut‐off point were calculated, with manual microscopy as the standard. Quantitative agreement in schistocyte counts between the two approaches was assessed using 95% limits of agreement, Bland‐Altman plots, intraclass correlation coefficient, and concordance correlation coefficient.

Results

Ninety‐seven blood samples (62 suspected TMA and 35 thalassaemia) were collected. ROC curve analysis of the analyser for determining schistocytosis showed an area under the curve of 0.803 (95% confidence interval, 0.689‐0.917, P < 0.001). A cut‐off point of 0.6% yielded 86.1% sensitivity, 77.8% specificity, 94.4% PPV, and 56.0% NPV. The automated schistocyte count did not quantitatively agree with schistocyte counts by microscopy, neither in all blood specimens (mean of difference: −1.09; 95% limits of agreement, −11.9 to 9.7) nor in the subgroups (TMA, −0.88; 95% limits of agreement, −6.60 to 4.84; thalassaemia, −2.4; 95% limits of agreement, −14.10 to 9.30). The differences in the estimation of fragmented red blood cells between the methods tended to increase at higher schistocyte counts.

Conclusion

Sysmex XN‐3000 can be used for qualitative measurement of schistocytosis, but should not be used as a quantitative tool for schistocyte counting. Improvements are needed before this analyser's schistocyte detection feature can be recommended for use in clinical practice.