Libyan Journal of Medicine

Log in or Register to get access to full text downloads.

Remember me or Register

Defining obstructive ventilatory defect in 2015

Zied Affes, Salaheddine Rekik, Helmi Ben Saad


Introduction: There is no clear consensus as to what constitutes an obstructive ventilatory defect (OVD): Is it FEV1/FVC<lower limit of normal (LLN) or <0.70 (respectively, physiological and operational definitions)? Aim: To determine, according to the two definitions, the percentage of subjects having an OVD among them explored in a lung function exploration laboratory.
Population and methods: This is a retrospective study including 4,730 subjects aged 17-85 years. Subjects were divided according to the presence [physio (+) or operat (+)] or absence [physio (-) or operat (-)] of an OVD, and into younger (<45 years, n=2,076), older (>45 years, n=2,654), smokers (n=1,208), and non-smokers (n=3,522) groups.
Results: For the total sample, the younger and older groups [mean+SD of age (years), respectively, 46.7+14.1; 33.9+7.4, and 56.8+9.1], the ‘physiological definition’ detected, respectively, 13.46, 43.22, and 5.09% more OVD than the ‘operational one’ (p<0.05). In addition, the operational definition, compared with the physiological one, overdiagnosed OVD in 2.33 and 0.44% of smokers and non-smokers, respectively, and  underdiagnosed it in 4.46% and 29.72% of smokers and non-smokers, respectively (p<0.05). Compared with the group ‘physio (-), operat (+)’, the ‘physio (+), operat (-)’ one was younger (74.2+4.7 years vs. 40.9+10.3 years) and had significantly higher FEV1 (62+13% vs. 78+17%) and FVC (71+15% vs. 93+19%).
Conclusion: The frequency of OVD much depends on the criteria used for its definition.

Keywords: obstructive ventilatory defect; FEV1/FVC; fixed threshold; lower limit of normal; spirometry; guideline

AJOL African Journals Online