Epidemiology of Venous Thromboembolism in the East Heng Joo NG Department of Haematology Singapore General Hospital Singapore
Early Literature Tinckler LF Br Med J 1964;1:502
Propagating a notion.. Hwang WS. Singapor Med J. 1968;9:276-9 29 cases of pulmonary embolism in 36,176 autopsies (0.08 %)
40 years on Asians VTE : Myth or fact?
MeSH terms venous thrombosis, pulmonary embolism, Asia, Asian continental ancestry group 436 citations, 63 papers meeting criteria
Epidemiologic Studies of VTE in Asians Population-based Post-mortem Selected high-risk groups Hospitalized patients
Population-based studies - Caucasians Year Study Site Study Type Annual DVT incidence Annual PE incidence 1991 Worcester, USA Retrospective, 379,953 residents 48 per 100,000 population 23 per 100,000 population 1998 Minnesota, USA 2000 Western France Retrospective, 103,670 residents Restrospective, 342,000 residents 2008 Europe Systematic review estimates 48 per 100,000 population 124 per 100,000 population 148 per 100,000 population 69 per 100,000 population 60 per 100,000 population 95 per 100,000 population
Population-based studies - Asians Br J Surg. 2004 Apr;91(4):424-8. Retrospective study of 2,082,245 admissions Incidence of DVT 17.1 per 100,000 population Incidence of PE 3.9 per 100,000 population
Ann Acad Med Singapore 2009;38:470-7 Assuming that 42.5% of the 2006 Singapore population was served by NHG, the estimated population-based incidence of VTE and PE is 57 and 15 per 100,000, respectively.
Population-based studies Comparison between Asians and Caucasians in Western Population Incidence of Idiopathic DVT and secondary VTE among ethnic groups in California White, R. H. et. al. Ann Intern Med 1998;128:737-740
Race VTE incidence (per 100,000 population) African Americans 141 Caucasians 104 Hispanics 55 Asians/Pacific Islanders 21 Keenan CR and White RH. Curr Opin Pulm Med. 2007
Keenan CR and White RH. Curr Opin Pulm Med. 2007
Am J Cardiol. 2000 Jun 1;85(11):1334-7.
Pulmonary thromboembolism in Asians/Pacific Islanders in the United States: analysis of data from the National Hospital Discharge Survey and the United States Bureau of the Census. Stein PD, Kayali F, Olson RE, Milford CE. Am J Med. 2004 Apr 1;116(7):435-42.
Population studies summarised Reported VTE incidence highest in European studies Comparisons between ethnic groups within population studies in the West show lower rates of symptomatic VTE among Asians Limited published population-based studies in Asia reported incidence of symptomatic VTE appears lower than reported Western incidence but is not insignificant
Post mortem studies
Pulmonary embolism is not uncommon results and implications of a five year study of 116 necropsies Lau G. Ann Acad Med Singapore. 1995;24:356-65 11,044 coroner s autopsies in Singapore Prevalence of 1.05%
Clinicopathological pattern of pulmonary thromboembolism in Chinese autopsy patients: comparison with Caucasian series. Chau KY, Yuen ST, Wong MP. Pathology. 1997 Aug;29(3):263-6. Significant pulmonary thromboembolism 4.7% Most were asymptomatic DVT more common in calf veins
Overall incidence in adult medical patients - 15.9%
Post-mortem studies summarised Comparative incidence of autopsyconfirmed deaths due to PE appears comparable between Asians and Caucasians in more recent studies Post-mortem incidence may vary considerably, depending on the patient pool and practices of the study site
Selected high-risk patient groups studies in Singapore and Malaysia Year Author Screening Method Population N Incidence 1989 Mitra Venography Proximal femur 72 9.7% fractures 1993 Kum CK Various Colorectal 129 4.7% (symptomatic) malignancies 1996 Dhillon KS Venography THR, TKR, femur 88 62.5% (20% proximal DVT) fractures 2000 Ruban Duplex scan TKR 100 14% (63.4% of total were distal DVT) 2004 Lim WW Doppler US Orthopaedic fractures 106 7.7% (at 5-7 POD, proximal DVT) 2006 De Silva Doppler US Acute stroke NA 30% (at 1 week) 45% (at 1 month) 2007 Tan SS Doppler US Acute stroke 44 2.4% (at 1 week) 4.8% (at 1 month
VTE Epidemiology Studies in Hong Kong Year Author Screening Population N Incidence Method 1979 Mok CK Venography Proximal femur fractures 53 53.3% 2002 Liu HS Various Hospitalised patients NA 16.6 per 100,000 2002 Chan LY Various Gynaecologic surgery 6077 5.1% (90 % distal) 2003 Ko PS Doppler THR and TKR 80 27.5% at 1 week Ultrasound 2004 Cheuk BL Various Public healthcare database NA DVT 17.1 per 100,000 PE 3.9 per 100,000 2005 Chan LY Doppler LSCS patients 93 O% at 3-7 days Ultrasound 2006 Leung V Doppler Ultrasound Hospitalised medical patients, with clinical symptoms or raised d- dimers 1754 1%
Deep vein thrombosis after total knee arthroplasty. Wang CJ et al Selected At-risk Groups Orthopaedic Surgery J Formos Med Assoc. 2000 Nov;99(11):848-53. Overall incidence of DVT 63.6% (95.6% distal DVT)
Selected high-risk Groups Orthopaedic Surgery J Thromb Haemost 2005; 3: 2664 70.
J Thromb Haemost 2005; 3: 2664 70.
J Thromb Haemost 2005; 3: 2664 70.
J Thromb Haemost 2005; 3: 28 34.
Adjudicated symptomatic VTE or sudden death at 1 month 1.5% J Thromb Haemost 2005; 3: 28 34.
Br J Anaesth. 1997 Jun;78(6):660-5 Symptomatic VTE in placebo group - 1.2% Total VTE in placebo group 37.3% Study method venography 43% proximal
DVT detected in 45% of patients between 25-30 days of ischemic stroke by Doppler ultrasound
Selected high-risk population summarised When subjected to a major provoking factor, the incidence of VTE in Asians and Caucasians are similar Asians tend to have more distal DVTs than proximal DVTs
Epidemiologic studies in hospitalised patients
VTE Trends among hospitalized patients in Singapore Study period 1989-90 1996-97 2002-03 Total admissions 48,864 202,869 109,217 Acute DVT 39 320 495 Acute DVT rate per 10,000 admissions (%) 7.9 (0.079%) 15.8 (0.158%) 45.3 (0.453%) 1. Kueh YK et al Ann Acad Med Singapore 1992 2. Lee LH et al Ann Acad Med Singapore 2002 3. Ng HJ and Lee LH Thromb Haemost 2008
VTE Trends among hospitalized patients in Singapore Discipline DVT rates (per 100 admissions) p-value 1989-90 2002-03 Orthopaedic 0.082 0.96 < 0.001 Medicine 0.099 0.507 <0.001 Other surgical disciplines 0.106 0.289 0.01 Gynaecology 0.069 0.141 0.48 Obstetrics 0.011 0 -
VTE Trends among hospitalized patients in Singapore 50 45 45.3 40 35 30 25 DVT per 10,000 admissions 20 15 15.8 10 5 0 7.9 1989-90 1996-97 2002-03
Hospitalized patient incidence in Singapore summarized Increasing incidence of VTE cases among hospitalized patients Marked increase in VTE rates likely accounted for by changes in clinicians attitudes towards VTE and possibly changes in disease patterns VTE burden among hospitalised patients is substantial
VTE in the East Conclusions, Future Research Questions In the general population, why are Asians less likely to clot? Why are clots in Asians more confined to distal rather than proximal veins? Can Asians be better risk stratified to guide prophylaxis strategies? What are the reasons for the increase in VTE incidence among hospitalised patients over the years?
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