Estimated risk of deep venous thrombosis among Chinese patients admitted to general medical wards

Large-scale correlation analysis of deep venous thrombosis and gut microbiota

Objective

Although previous studies have shown that gut microbiota may be involved in the occurrence of deep venous thrombosis (DVT), the specific link between the two remains unclear. The present study aimed to explore this question from a genetic perspective.

Materials and methods

Genome-wide association study (GWAS) summary data of DVT were obtained from the UK Biobank (N = 9,059). GWAS summary data of the gut microbiota were obtained from the Flemish Gut Flora Project (N = 2,223) and two German cohorts (FoCus, N = 950; PopGen, N = 717). All the participants were of European ancestry. Linkage disequilibrium score (LDSC) regression has great potential for analyzing the heritability of disease or character traits. LDSC regression was used to analyze the genetic correlation between DVT and the gut microbiota based on the GWAS summary data obtained from previous studies. Mendelian randomization (MR) was used to analyze the genetic causal relationship between DVT and the gut microbiota. We used the random effects inverse variance weighted, MR Egger, weighted median, simple mode, and weighted mode to perform MR analysis. We performed a sensitivity analysis of the MR analysis results by examining heterogeneity and horizontal pleiotropy.

Results

Linkage disequilibrium score analysis showed that Streptococcaceae (correlation coefficient = -0.542, SE = 0.237, P = 0.022), Dialister (correlation coefficient = -0.623, SE = 0.316, P = 0.049), Streptococcus (correlation coefficient = -0.576, SE = 0.264, P = 0.029), and Lactobacillales (correlation coefficient = -0.484, SE = 0.237, P = 0.042) had suggestive genetic correlation with DVT. In addition, the MR analysis showed that Streptococcaceae had a positive genetic causal relationship with DVT (P = 0.027, OR = 1.005). There was no heterogeneity or horizontal pleiotropy in the MR analysis (P > 0.05).

Conclusion

In this study, four gut microbes (Streptococcaceae, Dialister Streptococcus, Lactobacillales) had suggestive genetic correlations with DVT, and Streptococcaceae had a positive causal relationship with DVT. Our findings provide a new research direction for the further study of and prevention of DVT.

Epidemiology of pregnancy-associated pulmonary embolism in South Asian multi-ethnic country: Mortality trends over the last four decades

OBJECTIVE

To determine the cumulative incidence, time of occurrence and risk factors of pregnancy-associated pulmonary embolism (PE) in Singapore, and to review the maternal mortality ratio of PE over the last four decades.

STUDY DESIGN AND SETTING

In this retrospective epidemiology review, women with pregnancy-associated PE were identified via International Classification of Diseases codes and included if they had been objectively diagnosed on imaging with PE during pregnancy or within 6 weeks postpartum from 2004 to 2016 at KK Women's and Children's Hospital (KKH) and Singapore General Hospital (SGH) in Singapore. The medical records were reviewed and the time of occurrence of confirmed PE cases and risk factors for PE were noted.

RESULTS

There were 18 PE cases out of 174 708 deliveries, of which two were fatal, giving a cumulative incidence of PE at 1.03 per 10 000 deliveries and a mortality rate of 11.1%. The maternal mortality ratio is 1.14 per 100 000 deliveries, the lowest compared to that of the previous three decades (2.5-4.9 per 100 000 deliveries). Majority of PE (66.7%) occurred during the first 2 weeks postpartum. Cumulative incidence of postpartum PE was four times more in caesarean section compared to vaginal delivery at 1.58 per 10 000 deliveries and 0.40 per 10 000 deliveries, respectively.

CONCLUSION

Although the cumulative incidence of pregnancy-associated PE in Singapore is low, it is comparable to the United Kingdom (UK) and United States (US). Risk assessment and thromboprophylaxis have decreased PE mortality significantly during this period.

Venous thromboembolism in Asia – an unrecognised and under-treated problem?

Venous thromboembolism (VTE) has been perceived for a long time to be less common in Asian populations, particularly in the Far East, than in Western populations. Generally, thromboprophylaxis is not implemented as frequently as it should be in high-risk patients. However, recent prospective studies undertaken in Asian countries have demonstrated higher rates of VTE after major surgery and in medical wards, approaching those observed in Western populations. Risk factors for VTE are not different in Asian patients from those of Western patients with the exception of thrombophilic mutations. Deficiencies of the natural anticoagulants (protein S, protein C, and antithrombin) are the predominant thrombophilias in Asia whereas factor V Leiden and prothrombin G20210A gene mutation are not found or rarely reported. Further large well-designed clinical studies are needed to evaluate the magnitude of the risk of VTE and the appropriate use of thromboprophylaxis in different clinical situations.

Incidence of Deep Vein Thrombosis in Hospitalized Chinese Medical Patients and the Impact of DVT Prophylaxis

Objective. To evaluate the incidence of deep vein thrombosis in hospitalized Chinese medical patients and the impact of DVT prophylaxis. Methods. All cases of confirmed proximal DVT from 1 January 2005 to 31 December 2008 were reviewed retrospectively to determine the presence of risk factors and whether DVT developed: during hospitalization in medical wards or in case of readmission with a diagnosis of DVT within 14 days of discharge from a recent admission to medical wards. The impact of prophylaxis will be estimated by comparing the annual incidence of proximal DVT among medical patients hospitalized from 2005 to 2007 with that of 2008 (DVT prophylaxis commonly used). Results. From 1 January 2005 to 31 December 2008, 3938 Doppler ultrasound studies were performed for suspected DVT. Proximal DVT was diagnosed in 687 patients. The calculated incidence of proximal DVT among medical patients hospitalized for at least two days was 1.8%, 2%, and 1.7% for the year 2005, 2006, and 2007, respectively. The incidence was 1.1% for 2008 (P < .001). Conclusion. Proximal DVT was substantial in Chinese medical patients, and DVT prophylaxis might reduce such risk.

Thrombosis and bleeding disorders outside Western countries

The rapidly developing countries of Asia are witnessing substantial progress in the awareness of bleeding and thrombotic disorders as important health care problems. It has been thought for a long time that venous thromboembolism is very rare in Asia. Recent large studies that involved the majority of Asian countries demonstrated that this is not true, so that the practice of not using thromboprophylaxis in high-risk medical and surgical cases should be abandoned. The management of hemophilia and allied coagulation disorders has also dramatically improved in several Asian countries, due to the increased availability of blood products for replacement therapy coupled with the leadership role exerted by a few charismatic physicians, particularly in India and Thailand. As to the future, countries such as China and India have the capacity and expertise in biotechnology to consider the production of recombinant factors and gene transfer as the best strategies to tackle the management of persons with hemophilia in these densely populated and huge countries.