Timely detection of chronic obstructive pulmonary disease in primary health care
Introduction: One of the most important problems related to COPD is its worldwide underdiagnosis. The reasons for this are still debatable, but one frequently pointed out is a limited access to spirometry. In Portugal, this situation is also true, with many differences in the access to this exam in the context of primary health care. The purpose of this project was to validate a minispirometer and to evaluate the performance of screening questionnaires for selecting high risk patients for spirometry.
Methods: This was an observational, descriptive and validation study. It was approved by local and regional ethics committee. Patients 40 years old or above, with a smoking history and with no COPD diagnosis were invited to participate. They were subjected to screening questionnaires, AirSmart® minispirometer and spirometry. The results from the first two tools were compared to the spirometry, to calculate their correlation.
Results: A total of 337 patients were included; 62.3% male. Mean age 56.68 (± 10.14). All had a present or past smoking history, with a mean consumption of 31.59 (± 19.04) pack-years. The minispirometer mean results were: FEV1 3.00 (± 0.74), FVC 4.04 (± 0.89), FEV1/FVC 74.38 (± 6.65). These values were significantly similar to the spirometry results, being the correlations FEV1/FVC 0.848, FEV1 0.957, FVC 0.952 (p < 0.05). Using minispirometer FEV1/FVC to predict obstruction had sensitivity of 88.2%, specificity of 87%, positive predictive value of 44.8% and negative predictive value of 98.4%. None of the questionnaires’ questions presented a strong correlation with the spirometry results. Thirty-five (10.36%) new obstructed patients were found.
Discussion: These results confirm that this minispirometer can be an useful tool to screen high risk patients for the development of COPD. A cost-benefit analysis will now be performed to better understand the utility of using such tools in countries like Portugal.