The Utility of Spirometry in Assessment of Presumptive Diagnosis of Bronchial Asthma in a Nigerian Tertiary Hospital

Abstract

Context: Spirometry with reversibility testing is the gold standard for definitive diagnosis of bronchial asthma. However, even in those with established bronchial asthma reversibility test result may subsequently become negative. Spirometry results may also be normal during exacerbation-free intervals. Aims: This study assessed the role of spirometry in diagnostic evaluation of bronchial asthma and determined the ventilatory patterns of patients with presumptive diagnosis of bronchial asthma using spirometry and the proportion of those who showed positive reversibility test. Patients and Methods: This was a retrospective study carried out at a teaching hospital in Nigeria. This was an audit of consecutive patients with presumptive diagnosis of asthma referred for spirometry between January 2013 and June 2015. Spirometer with disposable mouthpieces, stadiometer, and salbutamol inhalers were used. The statistical analysis was done with Statistical Package for the Social Sciences version 20. Results: Eighty-nine participants did spirometry of whom 28 (31.5%) had additional postbronchodilator testing. Fifty (56.3%) participants were females (mean age of 42.17 ± 15.48 years). Normal, obstructive, restrictive, and mixed ventilatory patterns were found in 39 (43.8%), 31 (34.8%), 10 (11.2%), and 9 (10.1%) participants, respectively. Positive reversibility test result occurred in 15 (53.6%) participants, 9/19 obstructive (47.4%), and 6/9 mixed patterns (66.7%). Conclusion: Only a few patients with presumptive diagnosis of asthma were confirmed by spirometry. Spirometry is useful in asthma diagnosis, but clinicians should be aware of its limitations in diagnostic assessment. Although asthma is typically associated with obstructive spirometry, other spirometry patterns can occur.