Detecting reversible airway disease in those born preterm – which is the best test?

Abstract

Introduction: Spirometry identifies a bronchodilator response (BDR) in >30% of children born preterm; however developmental delays may inhibit the use of this test. We assessed the feasibility and sensitivity of spirometry and oscillometry to assess BDR in children and young-adults born very preterm (≤32 weeks gestation).

Methods: Preterm children (N=131; 10.3±2.3 years), young-adults (N=127; 19.3±1.4 yrs) and term-born controls (N=64) had BDR (400mcg salbutamol via spacer) assessed by spirometry and oscillometry. Significance thresholds were: spirometry (≥Δ12% (+Δ200ml in young-adults) FEV₁ or FVC); oscillometry (≥Δ 40% R_rs5; 50% X_rs5; 80% AX). Proportions were assessed using chi-square test.

Results: Oscillometry was more feasible in all age groups and cohorts. Being born preterm did not affect test feasibility (p>0.05). A BDR was identified in 30.9% (n=39) of preterm-born children via spirometry and/or oscillometry. Oscillometry identified an additional 8 (6.3%) children with BDR unable to perform spirometry. In preterm-born adults, oscillometry identified 1 additional BDR when spirometry could not be obtained (overall BDR incidence 30.4%; n=38). In those with acceptable spirometry and oscillometry (children n=95, 72.5%; adults n=117, 92.1%), agreement was poor between the tests. Oscillometry detected 23.5% (n=4, children) and 30.0% (n=9, adults) of individuals that met the spirometry criteria. Of the positive BDRs, 39.2% (n=11 children) and 18.9% (n=7 adults) met the oscillometry criteria only.

Conclusion: Oscillometry is more feasible, however poor agreement between oscillometry and spirometry suggests that complementary assessment is needed.