Early detection of chronic obstructive pulmonary disease in asymptomatic smokers using spirometry

Smokers with suspected COPD seek medical attention when they become dyspnoeic on mild to moderate exertion, but by than half of the ventilatory reserves are lost irreversibly. Hence it seems logical to diagnose COPD early before development of significant symptoms. Since smoking cessation in early COPD is found to reduce rapid decline of ventilatory function in smokers, its early detection in asymptomatic smokers is likely to motivate smokers to make an attempt to quit smoking thereby halting its progression to more advanced stage.

The selection of subjects was done by high risk population screening in various military institutions in and around Pune city of Maharashtra. Inclusion criteria included regular smokers, 30 years of age and above with no significant respiratory symptoms except for occasional cough and willing to undergo spirometry.

A total of 460 individuals were evaluated by spirometry. Overall airway obstruction was seen in 58 (12.60%) subjects. Mild obstruction was seen in 40 (68.9%) and moderate obstruction in 18 (31%) subjects. Airway obstruction was seen in 24 (8.82%) individuals who were less than 40 years of age and in 34 (18%) who were more than 40 years of age (p < 0.005). Obstruction was noticed in 42 (24.70%) out of 170 subject with smoking index > 200 and 16 (5.51%) out of 290 subjects with smoking index of < 200 (p < 0.005). In smokers more than 40 years of age and with smoking index more than 200 (n = 184), 48 (26%) had obstruction and in smokers less than 40 years of age and smoking index less than 200 (n = 276), 15 (5.43%) had obstruction (p < 0.005).

Early detection of COPD by spirometry especially in smokers more than 40 years of age and with smoking index of more than 200 is likely to reduce the overall burden of disease.