The use of microspirometry in detecting lowered FEV1 values in current or former cigarette smokers

COPD is an underdiagnosed disease. This study was undertaken to assess the value of microspirometry in detecting reduced FEV1 values in cigarette smokers, i.e., subjects at high risk for COPD.

A total of 611 smokers or ex-smokers with a smoking history >20 years and no previously-diagnosed lung disease were recruited (389 male, age 27-83 years, mean age 56 years, mean smoking history 35 pack years, 19% ex-smokers).

An FEV1 < 80% predicted on microspirometry was found in 44.6% of cases. The mean FEV1 was 2.8 litres (80.6% predicted, range 26-121%). This correlated well with values obtained from full spirometry (R=0.965, p<0.0001). Detailed questionnaire responses revealed that almost half of the subjects (48.2%) reported chronic cough and sputum production and 39.8% reported breathlessness during exercise.

Microspirometry finds a considerable number of smokers or ex-smokers with reduced FEV1 values. Microspirometry is quick to perform. All smokers with reduced microspirometry FEV1 values would benefit from smoking cessation, and all patients with reduced FEV1 values need to be considered for full spirometry to confirm if they actually have COPD.