Non-obstructive patterns of spirometry among obese patients presenting with symptoms and signs of mild to moderate asthma

Abstract

Background: Asthmatic patients typically show obstructive pattern on spirometry; with positive response to bronchodilators. However, there is paucity of data regarding presentation of obese patients with non-obstructive patterns of spirometry.
Methods: A sample of 295 known asthmatic patients (74% over-weights or obese and 26% nonobese) was selected from those attending respiratory clinic of Yastabshiron Hospital for follow up. A portable spirometer (All flow, Clement Clarke International, UK) was used for measurement of
FEV1, FVC, FEV1/FVC ratio and PEF for each patient. Measurements were carried out on presentation and then 15 minutes following inhalation of 0.5 mg salbutamol using a spacer.
Results: Typical obstructive pattern was found in only 17.4% of obese patients, normal pattern in 18.3%, restrictive in 45.9% and combined pattern in 18.3%. The relation between obesity and patterns of spirometry was found to be statistically insignificant (P= 0.808). Significant proportions
of all patterns showed positive reversibility tests (P= 0.000).
Conclusion: It is concluded that all patterns of spirometry are expected in obese patients with mild to moderate asthma. Reversibility tests are highly significant among asthmatic patients, irrespective to their spirometric pattern.

Key words: Obesity, Reversibility, FEV1, FVC