To the Editor: Pulmonary embolism (PE) used to be thought to be rare in China.1 Traditional teaching by such authorities as Snapper, who was highly regarded in old China as one of the most astute diagnosticians, was that PE was uncommon in China.2 As a matter of fact, he did not even mention it in his book “Chinese lessons to western medicine”,3 published in 1941. The rarity of pulmonary embolism was even more remarkable when one considered the widespread use of birth control pills among the Chinese women of child-bearing age.1
The recent article by Tan et al4 challenged this view. They reported an increase of PE in hospitalized patients from 0.27% during the early 1970s to 0.94% in this century, and concluded that PE is “an increasingly significant disease” in modern China. They offered two explanations: change in lifestyle and better diagnosis.
I like to propose two additional explanations for increased incidence of PE in modern China. First, the use of acupuncture anesthesia, which was quite popular in China in late 1960s and early 1970s and permitted early ambulation of the patients after major surgery, accounted for the low incidence of postoperative venous thromboembolism and pulmonary embolism in China.5 Because acupuncture anesthesia is seldom employed in China nowadays, especially for cardiothoracic surgery, this protective factor is no longer operative.
Second, obesity is a risk factor for venous thromboembolism and PE.6-8 China is facing an obesity epidemic.9 The number of obese people in China is increasing rapidly and will exceed 200 million by 2015.10
I therefore share the same concern of Tan et al4 that PE “deserves adequate attention”. However, despite its rising incidence, PE is largely a preventable disease. Control of such risk factors as lifestyle change and obesity will go a long way in reversing this trend.
1. Cheng TO. Medicine in modern China. J Am Geriatr Soc 1973; 21:289-313.
2. Cheng TO. Pulmonary embolism is no longer rare in China. Int J Cardiol Vasc Med 2005; 7: 82.
3. Snapper I. Chinese lessons to western medicine. New York: Interscience Publishers; 1941.
4. Tan XY, He JG, Zou ZP, Zhao YF, Chen BP, Gao Y,et al. Changes of the proportion and mortality of pulmonary thromboembolism in hospitalized patients from 1974 to 2005. Chin Med J 2006;119:998-1002.
5. Cheng TO. The current state of cardiology in China. Int J Cardiol 2004; 96:425-439.
6. Stein PD, Beemath A, Olson RE. Obesity as a risk factor in venous thromboembolism. Am J Med 2005; 118:978-980.
7. Kucher N, Tapson VF, Goldhaber SZ, DVT FREE Steering Committee. Risk factors associated with symptomatic pulmonary embolism in a large cohort of deep vein thrombosis patients. Thromb Haemost 2005; 93:494-498.
8. Kearon C. Obesity, cigarette smoking and hypertension were associated with increased risk of pulmonary embolism in women. Evid Based Cardiovasc Med 1997; 1:67.