SESSION TITLE: Asthma Posters I
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 29, 2014 at 01:30 PM - 02:30 PM
PURPOSE: Bronchial Asthma(BA) is an airway disease manifested by increased airway reactivity. A 20% or more of improvement in PEFR after inhalation of bronchodilator(BD) can be used to confirm the diagnosis of BA. Ozturk, et al suggest that the clinical value of PEFR measurements in the diagnosis of reversible obstructive airway disease was less reliable than FEV1. FEF 25-75 is a reflection of small airway patency. Pediatric studies by Devika S Rao, et al have shown that variability of FEF 25-75 by 30% should be considered a potentially important spirometric variable that can be used as a marker of BD responsiveness. Our objective was to compare which one between PEFR 20% variability vs FEF 25-75 variability of 30% correlates better with presence of BD response defined by ATS as an increase in FEV1 by 12% and 200mls in patients with BA.
METHODS: Inclusion criteria were non smokers, with a diagnosis of BA, normal DLCO on Pulmonary Function Tests(PFT). Exclusion criteria were smokers, COPD, CT chest suggestive of emphysema, low DLCO. 161 PFT’s conducted at Interfaith Medical Center between 2008-2013 were obtained. Patients were divided into groups with and without BD response respectively as defined by ATS criteria. Out of 161 patients included in our study 142 patients did not show BD response. The changes in PEFR & FEF25-75 in response to bronchodilator were compared among these two groups. Statistical analysis was done using SPSS 17.0.
RESULTS: Changes in mean PEFR & FEF 25-75 between these two study groups were statistically significant (40.2 vs -.8 and 91.8 vs 22.4 respectively, p<0.05). PEFR variability with bronchodilator had a better positive correlation with the improvement in FEV1 when compared to FEF25-75 variability (r=. 53 & .22 respectively p<0.05). Increment in PEFR by 20% and FEF25-75 by 30% both had a specificity of 86.6% to anticipate adequate response to bronchodilators with a negative predictive value(NPV) of 95.3% and 93.8% respectively.
CONCLUSIONS: Based on these results, PEFR and FEF 25-75 variability correlate well with BD response however PEFR has better correlation.
CLINICAL IMPLICATIONS: FEF25-75 can be used to identify reversible airway obstruction with good specificity and NPV although it has lesser correlation than PEFR. Further studies need to be done comparing them in patients without bronchodilator response.
DISCLOSURE: The following authors have nothing to disclose: Vikram Oke, Rakesh Vadde, Abhisekh Sinha Ray, Mohammad Raihan Azad, Prajakta Mungikar, Sai Wan, Meenakshi Ghosh, Saurav Pokharel, Bikash Bhattarai, Bhradeev Sivasambu, Santu Saha, Rawshan Basunia, Charles Agu, Ramchander Eluri, Francis Schmidt
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