One might recall deep vein thrombosis (DVT) dominating the news several years ago in relation to travelling long-distance in economy-class flights. The hype about it has died down somewhat.
However, despite greater awareness of the syndrome - that of a blood clot forming, moving through the blood and becoming stuck in the brain or other organs - being linked to flying, its actual danger is more present on the ground than high above it.
The cases that surface in the West each year happen more often in post-orthopaedic surgery patients than among travellers in "cattle class".
Lifestyle factors also pre-dispose people to the condition.
The biggest group at risk of DVT are those who have had surgery or long hospital stays; those who sit for prolonged periods, or who are pregnant or have heart failure and acute infections such as pneumonia are also at risk.
Tay Jam Chin, a head of department and senior consultant in general medicine at Tan Tock Seng Hospital (TTSH), said: "It is related to increasing age, obesity, the use of oral contraceptives and hormone replacement therapy and genetic predisposition."
DVT does not discriminate by gender or race, but is more likely in the elderly, mainly because they are less mobile, he added.
TTSH and Singapore General Hospital (SGH) recently took part in the largest clinical trial which proved the efficacy of an oral anti-coagulant in treating acute DVT.
DVT is on the rise here.
TTSH has been receiving more new patients with DVT and pulmonary embolism (PE), which is specifically a blockage of the main artery in the lung, a condition that is fatal if not treated in time. There were 125 DVT/PE cases in 2009 and 167 last year.
SGH's Ng Heng Joo of the department of haematology said that there were 29 cases of PE among the 36,176 autopsies done in the 1950s and 60s, indicating a prevalence of 0.8 per 1,000 patients. By the 90s, the prevalence was 1.05 per cent.
SGH has seen 45.8 cases of DVT among hospitalised patients out of 10,000 admissions (0.458 per cent).
DVT blocks blood flow and causes swelling and pain. Common symptoms include leg pain or tenderness, cramping that intensifies over several days, redness of the skin or a rash, warmth at the site or swelling caused by fluid retention. Some patients show no symptoms.
The clinical trial TTSH and SGH took part in was done across 252 centres in 32 countries and involved more than 3,000 patients globally.
The hospitals compared the effectiveness of orally-administered Xarelto (Rivaroxaban) from 2007 to 2009 against the standard care of giving a combination of the two blood thinners heparin and warfarin to DVT/PE patients.
Xarelto showed its potential over current treatments. Without it, up to a quarter of post-operative patients could develop DVT or PE, said Assoc Prof Tay; with treatment, the risk fell to 3 per cent.
Xarelto is the first single oral treatment option for DVT and prevention of recurring DVT/PE.
While current treatments using injections or warfarin require the patient to be continually monitored, Xarelto does not. It is also less likely to interact with foods or other drugs the patient takes.
Xarelto can also potentially free up hospital beds, since treatment can carried out on outpatients.