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[Early detection of smoking related chronic obstructive pulmonary disease in Vietnam].

INTRODUCTION
Epidemiological studies of chronic obstructive pulmonary disease (COPD) are rare in the developing countries, particularly in Viet Nam where the consumption of tobacco continues to increase. The aim of this study was to evaluate the feasibility of early screening of smokers for bronchial obstruction using the Piko-6 apparatus.


MATERIALS AND METHODS
Smokers over 40 years of age who had smoked for more than 10 years were included. The subjects were classified into 3 groups according to the degree of bronchial obstruction measured by the Piko-6. (group 1: FEV1/FEV6>0.8; group 2: 0.7-0.8; group 3:<0.7). The smokers in group 3 and a sample of the smokers in groups 1 and 2 were recalled for full spirometric assessment.


RESULTS
2397 smokers were included, comprising 2130 active smokers and 267 ex-smokers. The mean age was 52 +/- 13 years. The mean smoking history was 24 +/- 13 pack years. 267 smokers from the 3 groups responded to the recall for full investigation. The prevalence of COPD detected by the Piko-6 in the study population was 13.5%. For the threshold FEV1/FEV6<0.7 and with the detected prevalence, the Piko-6 had a sensitivity of 97.8%, a specificity of 93.8%, a positive predictive value of 71% and a negative predictive value of 99.6% (confidence interval 95%).


CONCLUSIONS
The Piko-6 is a useful tool for the early screening for COPD in smokers in a developing country where the prevalence of this disease appears to be under estimated.