Are We Detecting Enough Deep Vein Thrombosis/Pulmonary Embolism?

Dear Editor,

Few common medical conditions are as difficult to diagnose as pulmonary embolism. As many as 80% of patients with pulmonary embolism or deep vein thrombosis identified during the postmortem examination are not clinically suspected of having the condition before they die. 1-3 In addition, both deep venous thrombosis and pulmonary embolism manifest few specific signs and symptoms, and there are well-recognized problems with the accuracy of current imaging modalities for detecting venous thromboembolism.

In the last issue of the Archives of Iranian Medicine, Nikparvar Fard, et al., in their article"pulmonary embolism and deep vein thrombosis in northern Iran", 4 in a chart review, solely based on discharge diagnosis, have identified some patients with venous thromboembolism and gave a hospital incidence of 9/10,000. Considering the poor methodology used, how one can rely on this very underestimated incidence, compare it with the results of other reports, and assess the validity of the presented risk factors?

 

F. Habibzadeh, M.D,
NIOC Outpatients Polyclinics,
Shiraz, Iran.

References

  1. Rubinstein I, Murray D, Hoffessstein V. Fatal pulmonary emboli in hospitalized patients, Arch Intern Med 1988; 140: 1425.
  2. Sandler DA, Martin JF. Autopsy proven pulmonary embolism in hospital patients; are we detecting enough deep vein thrombosis? JR Soc Med 1989; 82(4): 203-5.
  3. Mckelvie PA. Autopsy evidence of pulmonary thromboembolism. Med J Aust 1994; 160 (3): 127-8.
  4. Nikparvar Fard M, Zahed Pour Anaraki MR. Pulmonary embolism and deep vein thrombosis in northen Iran. Arch Irn Med 1999; 2(3): 136-42.

Author’s reply

Dear Editor,

We welcome the letter on "pulmonary embolism and deep vein thrombosis in northern Iran" by F.Habibzadeh As we mentioned in our article "because the signs and symptoms of venous thromboembolism (VTE) are nonspecific and may be confused with a variety of other cardiopulmonary disorders, presenting in a similar way, the total incidence and mortality rates of VTE are still uncertain."1,2 The objective of our study was to determine the hospital incidence and case fatality rates of diagnosed cases of VTE in Imam Hospital.

All the comparisons made were with the methodologicaly same studies.3-9 Therefore, our comment on the lower incidence of VTE in Iran than Western countries is logical. Although this study, like all other retrospective studies on diagnosed cases of VTE, may underestimate the incidence rate of VTE, but other results including risk factors and demographic characteristics of patients are essentialy unchanged.

A decent methodology must be in accordance with the objective of the study. It was unfair to label our study as poor methodology merely because it was a retrospective medical records review, while most of notable studies on the epidemiology of VTE used the same methodology. If we were to determine the total incidence of the diagnosed, undiagnosed, and silent episodes10 of VTE in the hospital, we whould plan another methology, which, in that case, to our knowledge, will be unique and uncomparable to other studies.

M. Nikparvar Fard MD,
Tehran, Iran

Reference

  1. Goldhaber SZ, Hennekens CH, Evans DA, et al. Factors associated with correct antemortem diagnosis of major pulmonary embolism. Am J Med 1982; 73: 822-6
  2. Bergquist D, Lindbald B. A 30-year survey of pulmonary embolism verified at autopsy: An analysis of 1274 surgical patients. Br J Surg 1985; 72: 105-8
  3. Anderson FA Jr, Wheeler HB. Phisician practices in the management of venous thrombosis: A community-wide survey. J Vasc Surg 1992; 16: 707-14
  4. Anderson Jr, Wheeler HB, Goldberg RJ, et al. A population-based thrombosis and pulmonary embolism, the Worcester DVT study. Arch Intern Med 1991; 151: 933-38
  5. Igbinovia A, Malik GM, Grillo IA, et al. Deep venous thrombosis in Assir region of Saudi Arabia, case control study. Angiol 1995; 46: 1107-13
  6. Alpert JS, Smith R, Carison J, et al. Mortality in patients treated for pulmonary embolism. JAMA 1976; 236: 1477-80
  7. Woo KS, Tse LKK, Tse CY, et al. The prevalence and pattern of pulmonary thromboembolism in the Chinese in Hong Kong. Int J Cardio 1988; 20: 373-80
  8. Kniffin WD JR, Baron JA, Barrett J, et al. The epidemiology of diagnosed pulmonary embolism and deep venous thrombosis in the elderly. Arch Intern Med 1994; 154: 861-6
  9. Nylander G, Olvercrona H, Hedner U. Earlier and concurrent morbidity of patients with acute lower leg thrombosis. Acta Chir Scand 1977; 143: 425-9
  10. Huisman MV, Buller HR, Cate J WT, et al. Unexpected high prevalence of silent pulmonary embolism in patients with deep venous thrombosis. Chest 1989; 95: 498-502

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