World Thrombosis Day 2026: Blood-Clot Prevention Must Keep Pace With Hospital Care
Dr Andrew Choong's opinion article for World Thrombosis Day was published by Cambodianess on 7 October 2026. This post summarises the argument for patients in Singapore and across the region, and explains what it means for anyone going into hospital.
World Thrombosis Day falls on 13 October every year. It does not get the attention given to heart attack and stroke, yet the campaign behind it estimates that one in four deaths worldwide involves a blood clot of some kind. The clots that this day is really about are the quiet ones: a deep vein thrombosis in the leg that can break off and travel to the lungs as a pulmonary embolism. Together they are called venous thromboembolism, and most of them are preventable.
Why write about this for Cambodia?
Because the argument applies to every health system that is growing, and it is easiest to see where growth is fastest. Cambodia, like much of Southeast Asia, is bringing far more people into hospital than it did twenty years ago: more operations, more cancer treatment, far more births in facilities and a sharp rise in caesarean sections. Every one of those is good news. Each also adds to the number of people who are, for a few weeks, at raised risk of a clot. The article asks that prevention keep pace with that progress, and proposes four steps that any hospital system can take.
Are blood clots really a problem in Asian patients?
For a long time doctors in this region were taught that venous clots were a Western disease. A systematic review of Asian studies found rates at roughly 15 to 20 per cent of Western figures, but rising steadily, and the Asian venous thromboembolism guidelines link that rise to ageing populations, dietary change and more obesity and diabetes. Those trends are as true of Singapore as of Phnom Penh. The practical problem with the old belief is that it lingers: a swollen calf is put down to a strain, breathlessness to a chest infection, and the diagnosis is made late.
Where do most clots come from?
Hospital. Up to 60 per cent of venous clots occur during a hospital stay or within 90 days of leaving one. Surgery, serious injury, cancer and days spent in bed all slow the blood in the leg veins and make it more likely to clot. Pregnancy and the six weeks after delivery carry about four times the usual risk, and a pooled analysis found the risk after a caesarean section to be about four times that after a vaginal birth. A new mother with a swollen, painful leg or sudden breathlessness needs to be seen urgently, not reassured.
What does prevention involve?
Nothing new and nothing expensive. Getting patients moving early after an operation, compression devices on the legs during and after surgery, and low-dose blood-thinning injections for those at higher risk have all been standard practice for decades. The gap is in applying them consistently. The ENDORSE study looked at more than 68,000 patients in 358 hospitals across 32 countries: about half were at risk of a clot, and only about half of those received the recommended prevention. In some Asian countries surveyed the figure was close to zero.
What did the article propose?
Four steps, in order of effort. First, assess every adult on admission with a one-page checklist covering age, reason for admission, mobility, cancer, pregnancy and any previous clot, as the Asian guidelines already recommend. Second, include maternity care: every woman who has a caesarean section should be assessed for clot risk before she goes home and told which symptoms should bring her back. Third, keep a simple register of diagnosed clots at the major referral hospitals, so that the scale of the problem, and whether prevention is working, becomes visible. Fourth, teach the public the warning signs.
What are the warning signs?
In the leg: swelling, pain, warmth or redness, usually in one calf, which should be seen by a doctor the same day. In the lungs: sudden breathlessness, chest pain that is worse on breathing in, a racing heartbeat, or coughing up blood. These are emergencies. In Singapore, call 995.
What can you do yourself?
If you or a relative is admitted to hospital, ask two questions: what is my risk of a blood clot, and what is being done to reduce it? After an operation, get moving as soon as you are allowed. On long flights and long road journeys, walk when you can and flex your ankles when you cannot. Women starting a combined contraceptive pill or hormone therapy should mention any personal or family history of clots. None of this is complicated; it is a matter of knowing to ask.
“Cambodia has made great strides in bringing people into hospital for care. The next step is to make sure a preventable clot does not undo that care.”
Dr Andrew Choong, Cambodianess, 7 October 2026
Read the full article: As More Cambodians Are Treated in Hospital, Blood-Clot Prevention Must Keep Pace (Cambodianess, 7 October 2026). Other media features are collected on the In the Media page.
Preparing for a vascular review
If you have had a swollen or painful leg, a clot in the past, or persistent leg swelling after a clot, a vascular review can establish whether the deep veins are affected and what, if anything, needs to be done. The DVT page explains how a clot is assessed with duplex ultrasound, and the DVT treatment page covers blood thinners, clot removal and when each is considered. Patients travelling from Cambodia, Vietnam, Indonesia, Myanmar or the Philippines can read how to arrange a review on the international patients page. To make an appointment, use the contact page.